Diagnostic Aids

CCRM interfaces with the EEC-V system to provide control for cooling fan and A/C clutch. CCRM also contains EEC-V power relay, which provides battery power (VPWR) to the Powertrain Control Module (PCM) and EEC-V system. Perform this test only when instructed by QUICK TEST or if directed by a system test. This test is only intended to diagnose the following:

Constant Control Relay Module (CCRM)
Harness Circuits (B+, VPWR, FC, LOW FAN PWR, HIGH FAN PWR, GND, LFC, HFC, ACCS, A/C CLUTCH PWR & WAC). See Fig 1-Fig 3
Powertrain Control Module (PCM)

To prevent replacing good components, be aware the following non-EEC related components or systems may be at fault:

A/C System
Fuel System
Starting & Charging System

Fig 1: Identifying CCRM Circuits (Escort)

Courtesy of FORD MOTOR CO.

Fig 2: Identifying CCRM Circuits (Mustang 3.8L)

Courtesy of FORD MOTOR CO.

Fig 3: Identifying CCRM Circuits (Mustang 4.6L)

Courtesy of FORD MOTOR CO.

1) Check VPWR Circuit Continuity

Turn ignition switch to OFF position. Disconnect IAC valve connector. Disconnect CCRM connector. See CCRM LOCATIONS table. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between VPWR terminal at IAC harness connector and terminals No. 12 and 24 at CCRM harness connector. See Fig 4. If both resistance measurements are less than 5 ohms, reconnect IAC and go to next step. If any resistance measurement is 5 ohms or more, repair open in VPWR circuit between CCRM and splice to IAC valve.

CCRM LOCATIONS

Application	Location
Escort	In Left Front Of Engine Compartment
Mustang	Mounted On Bracket, Behind Engine Coolant Reservoir

Fig 4: Identifying CCRM Connector Terminals

Courtesy of FORD MOTOR CO.

2) Check For Battery Voltage & IGN START/RUN Voltage To CCRM

Using a DVOM, measure voltage between negative battery terminal and terminals No. 8 and 10 at CCRM harness connector. Note voltage. Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and terminal No. 13 at CCRM harness connector. If all voltage measurements are more than 10.5 volts, go to next step. If any voltage measurement is 10.5 volts or less, check related fuses. If fuse is blown, check for short to ground in B+ or IGN START/RUN circuits. Repair as necessary and replace fuse. If fuses are okay, repair open in B+ or IGN START/RUN circuit.

3) Check CCRM Ground Circuit

Turn ignition switch to OFF position. Leave CCRM disconnected. Using a DVOM, measure voltage between terminals No. 8 and 15 at CCRM harness connector. If voltage is more than 10.5 volts, replace CCRM. If voltage is 10.5 volts or less, repair open in ground circuit (terminal No. 15).
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 15) . No test procedures have been omitted.

15) KOEO & KOER DTC P1479: Check High Fan Control (HFC) Relay

DTC P1479 indicates HFC primary circuit failure. Following are possible causes for this fault.
- Open Or Shorted Circuit
- Faulty CCRM
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to OFF position. Disconnect CCRM connector. See CCRM LOCATIONS table. Using a DVOM, measure resistance between terminals No. 17 and 24 at CCRM harness connector. See Fig 4. Resistance should be 65-100 ohms. Using a DVOM, measure resistance between terminal No. 17 and terminals No. 1 through 11, 13, 15 and 21 at CCRM harness connector. Each resistance should be more than 1000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace CCRM.

16) Check HFC Circuit Continuity

Turn ignition switch to OFF position. Disconnect CCRM and PCM harness connectors. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between PCM harness connector terminal No. 17 (Escort) or No. 46 (Mustang) and terminal No. 17 at CCRM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in HFC circuit.

17) Check HFC Circuit For Short To Power

Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and PCM harness connector terminal No. 17 (Escort) or No. 46 (Mustang). If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to power in HFC circuit.

18) Check HFC Circuit For Short To Ground

Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between PCM harness connector terminal No. 17 (Escort) or No. 46 (Mustang) and negative battery. If resistance is 10 k/ohms or less, repair HFC circuit short to ground. If resistance is more than 10 k/ohms, connect scan tool to DLC. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command high speed fan ON and wait 10 seconds. Command high speed fan OFF. If high speed fan turns on and off as expected, disregard DTC P1479. Repeat QUICK TEST and service any DTCs as necessary. If high speed fan does not turn on and off as expected, replace PCM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 18) to step 20) . No test procedures have been omitted.

20) KOEO & KOER DTC P1474: Check Fan Operation

This DTC indicates primary circuit failure in Low Fan Control (LFC) circuit or Fan Control (FC) circuit for single cooling fan systems. Following are possible causes for this fault.
- Open Or Shorted Circuit
- Faulty CCRM
- Faulty Powertrain Control Module (PCM)
Turn ignition switch to ON position. If cooling fan runs continuously, go to step 24). If cooling fan does not run continuously, go to next step.

21) Check FC/LFC Circuit For Short To Ground

Turn ignition switch to OFF position. Disconnect CCRM connector. Disconnect scan tool from Data Link Connector (DLC). Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between terminal No. 14 at CCRM and negative battery terminal. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in FC or LFC circuit.

22) Check Fan Operation

Connect CCRM connector. Leave PCM disconnected. Turn ignition switch to ON position. If cooling fan runs continuously, replace PCM. If cooling fan does not run continuously, replace CCRM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 24) . No test procedures have been omitted.

24) Check FC/LFC Circuit Continuity

Disconnect CCRM connector. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between PCM harness connector terminal No. 45 (except Mustang 4.6L) or No. 19 (Mustang 4.6L) and terminal No. 14 at CCRM harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FC or LFC circuit.

25) Check FC/LFC Circuit For Short To Power

Turn ignition switch to ON position. Using a DVOM, measure voltage between negative battery terminal and terminal No. 14 at CCRM. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to power in FC or LFC circuit.

26) FC/LFC Circuit Fault Isolation Check

Turn ignition switch to OFF position. Reconnect CCRM connector. Connect a jumper wire between PCM harness connector terminal No. 45 (except Mustang 4.6L) or No. 19 (Mustang 4.6L) and negative battery terminal. If cooling fan continues to run, replace CCRM. If cooling fan does not run continuously, replace PCM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 26) to step 30) . No test procedures have been omitted.

30) Continuous Memory DTC P1474: Check FC/LFC Circuit For Open Circuit Or Short To Power

This DTC indicates a circuit failure has occurred on Fan Control (FC) circuit (Mustang 3.8L) or Low Fan Control (LFC) circuit (Escort and Mustang 4.6L). Turn ignition switch to OFF position. Disconnect cooling fan connector. Connect a test light between negative battery terminal and LOW FAN PWR (FAN PWR on Mustang 3.8L) terminal at cooling fan harness connector. See Fig 1-Fig 3 . Turn ignition switch to ON position. Test light should be off. Check for indication of fault (test light blinks or turns on) while performing the following:
- Shake and bend FC/LFC circuit between CCRM and PCM.
- Lightly tap CCRM to simulate road shock.
If fault is indicated, isolate fault and repair as necessary. If fault is not indicated, go to next step.

31) Check LFC/FC Circuit For Short To Ground

Leave cooling fan connector disconnected and test light connected. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command low speed fan ON. Test light should be on. Check for indication of fault (test light blinks or turns off) while performing the following:
- Shake and bend FC/LFC circuit between CCRM and PCM.
- Lightly tap CCRM to simulate road shock.
If fault is indicated, isolate fault and repair as necessary. If fault is not indicated, problem is intermittent and cannot be duplicated at this time.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 31) to step 35) . No test procedures have been omitted.

35) Continuous Memory DTC P1479

This DTC indicates that High Fan Control (HFC) circuit failure has occurred. Turn ignition switch to OFF position. Disconnect cooling fan connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Connect a test light between negative battery terminal and high fan power circuit terminal at cooling fan harness connector. See Fig 1 or Fig 3 . Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command high speed fan ON. Test light should be on. Check for indication of fault (test light blinks or turns off) while performing the following:
- Shake and bend HFC circuit between CCRM and PCM.
- Lightly tap CCRM to simulate road shock.
If fault is indicated, isolate fault and repair as necessary. If fault is not indicated, go to next step.

36) Check HFC Circuit For Short To Ground

Turn ignition switch to ON position. Command high speed fan OFF. Test light should be off. Check for indication of fault (test light blinks or turns on) while performing the following:
- Shake and bend HFC circuit between CCRM and PCM.
- Lightly tap CCRM to simulate road shock.
If fault is indicated, isolate fault and repair as necessary. If fault is not indicated, problem is intermittent and cannot be duplicated or identified at this time.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 36) to step 40) . No test procedures have been omitted.

NOTE: For proper results of the following test step, no DTCs must have been present during QUICK TEST.

40) Check Cooling Fan Operation
Turn ignition switch to OFF position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command cooling fan ON. Check fan operation. On 2-speed fan applications, check both fan speeds (wait 30 seconds after commanding high speed fan on). If fan does not operate, go to next step. If fan operates (all speeds), no problem is indicated at this time. Fault may be intermittent.

41) Cooling Fan Concern

On Mustang 3.8L, go to next step. On all other models, during operational check of both fan speeds, if fan did not operate at any speed, stay in OUTPUT TEST MODE and go to next step. If fan operated at one fan speed, go to step 50).

42) Cooling Fan Does Not Operate At Any Speed

Turn ignition switch to ON position. Disconnect cooling fan. Command fan ON (high speed for 2-speed applications). Using a DVOM, measure voltage between negative battery terminal and HIGH FAN PWR (FAN PWR on Mustang 3.8L) terminal at cooling fan harness connector. If voltage is 10 volts or less, go to next step. If voltage is more than 10 volts, go to step 45).

43) Check B+ Circuit To Fan Relays

Turn ignition switch to OFF position. Ensure cooling fan is disconnected. Disconnect CCRM connector. Using a DVOM, measure voltage between negative battery terminal and terminals No. 3 and 4 at CCRM harness connector. If both voltage measurements are more than 10 volts, go to next step. If any voltage measurement is 10 volts or less, fault exists in B+ circuit. Check cooling fan related fuse/fuse links. If fuse/fuse link is blown, check for short to ground in B+ circuit. Repair as necessary. If fuse/fuse link is okay, check for open B+ circuit. Repair as necessary, reconnect all components and recheck system operation.

44) Check Power To Fan(s) Circuit

Turn ignition switch to OFF position. Disconnect CCRM connector. See CCRM LOCATIONS table. Ensure cooling fan is disconnected. Perform appropriate procedure:
- Mustang 3.8L
  
  Using a DVOM, measure resistance of FAN PWR circuit between cooling fan harness connector and terminal No. 2 at CCRM harness connector. If resistance is less than 7 ohms, go to step 70). If resistance is 7 ohms or more, locate and repair open circuit between cooling fan and CCRM. After repair is complete, reconnect all components and recheck system operation.
- All Models Except Mustang 3.8L
  
  Using a DVOM, measure resistance of HIGH FAN PWR circuit between cooling fan harness connector and terminal No. 6 at CCRM harness connector. Using a DVOM, measure resistance of LOW FAN PWR circuit between cooling fan harness connector and terminal No. 2 of CCRM. If both resistance measurements are less than 7 ohms, replace CCRM. If any resistance measurement is 7 ohms or more, locate and repair open circuit(s) between cooling fan and CCRM. After repair is complete, reconnect all components and recheck system operation.

45) Check Cooling Fan Ground Circuit

Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between negative battery terminal and ground circuit terminal at cooling fan harness connector. If resistance is 5 ohms or more, locate and repair open ground circuit. Reconnect all components and recheck system operation. If resistance is less than 5 ohms, replace cooling fan. Reconnect all components and recheck system operation.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 45) to step 50) . No test procedures have been omitted.

50) Determine Which Fan Speed Is Operational

If low speed fan is functioning properly, but high speed fan is inoperative, go to step 65). If low speed fan is not functioning properly, go to next step.

51) Low Speed Cooling Fan Inoperative

Turn ignition switch to ON position. Remain in OUTPUT TEST MODE. Disconnect cooling fan. Command low speed fan ON. Using a DVOM, measure voltage between negative battery terminal and LOW FAN PWR terminal at cooling fan harness connector. If voltage is more than 10 volts, replace cooling fan. Reconnect all components and recheck system operation. If voltage is 10 volts or less, go to next step.

52) Check Low Fan Power Circuit Continuity

Turn ignition switch to OFF position. Disconnect CCRM connector. Using a DVOM, measure resistance between LOW FAN PWR terminal at cooling fan harness connector and terminals No. 1 and 2 at CCRM harness connector. See Fig 4. If both resistance measurements are less than 5 ohms, go to step 70). If any resistance measurement is 5 ohms or more, locate and repair open in LOW FAN PWR power circuit. Reconnect all components and recheck system operation.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 52) to step 65) . No test procedures have been omitted.

65) High Speed Cooling Fan Inoperative

With scan tool still in OUTPUT TEST MODE, disconnect cooling fan. Turn ignition switch to ON position. Command high speed cooling fan ON. Using a DVOM, measure voltage between negative battery terminal and HIGH FAN PWR terminal at cooling fan harness connector. If voltage is 10.5 volts or less, go to next step. If voltage is more than 10.5 volts, replace cooling fan. Reconnect all components and recheck system operation.

66) Check High Fan Power Circuit Resistance

Turn ignition switch to OFF position. Disconnect CCRM connector. Using a DVOM, measure resistance of HIGH FAN PWR circuit between terminal No. 6 at CCRM harness connector and cooling fan harness connector. If resistance is less than 5 ohms, go to step 70). If resistance is 5 ohms or more, locate and repair open in HIGH FAN PWR circuit. Reconnect all components and recheck system operation.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 66) to step 70) . No test procedures have been omitted.

70) Accessing Parameter Identification (PID)

A inoperative high speed or low speed fan can be caused by a primary circuit fault, even though a DTC was not set. Check if scan tool being used is capable of accessing PID values while in OUTPUT TEST MODE. If PID access is possible, go to next step. If PID access is not possible, go to step 73) (if fan inoperative on Mustang 3.8L or if low speed fan inoperative on all other models) or step 16) (if high speed fan inoperative).

71) Check Operation Of Primary Fan Circuits

Reconnect all connectors. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Perform the appropriate test procedure as follows:
- Low Speed Fan Inoperative (Fan Inoperative On Mustang 3.8L)
  
  Using scan tool, select LFCA and LFCF PIDs from PID/DATA MONITOR & RECORD menu. With low speed fan off, LFCA PID should indicate OFF and LFCF PID should indicate NO. Command low speed fan ON. LFCA PID should indicate ON and LFCF PID should still indicate NO.
- High Speed Fan Inoperative
  
  Using scan tool, select HFCA and HFCF PIDs from PID/DATA MONITOR & RECORD menu. Command high speed fan ON. HFCA PID should indicate OFF and LFCF PID should indicate NO. Command high speed fan ON. HFCA PID should indicate ON and HFCF PID should still indicate NO.
On all models, if LFCF PID of HFCF PID indicated YES with fan commanded on or off, a primary circuit fault is detected. Go to step 15) (if HFCF PID was yes) or go to step 20) (if LFCF PID was yes). If LFCF PID of HFCF PID indicated NO with fan commanded on or off, primary circuits are okay. Replace CCRM. Verify applicable FAN PWR circuit is not shorted to ground. Recheck cooling fan operation.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 71) to step 73) . No test procedures have been omitted.

73) Check FC Or LFC Circuit For Short To Ground

Turn ignition switch to OFF position. Disconnect scan tool from DLC. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between terminal No. 14 at CCRM and negative battery terminal. If resistance is more than 10 k/ohms, replace CCRM. Ensure appropriate FAN PWR circuit is not shorted to ground. If resistance is 10 k/ohms or less, repair short to ground in LFC or LF circuit.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 73) to step 80) . No test procedures have been omitted.

80) Cooling Fan Always Runs, No DTCs Present

Start engine. Using scan tool, select ACP PID from PID/DATA MONITOR & RECORD menu. If PID value indicates CLOSED, leave engine running and go to next step. If PID value indicates OPEN, go to step 82).

81) Check A/C High Pressure Switch

Disconnect A/C high pressure switch. Again, view ACP PID. If PID value indicates CLOSED, turn ignition switch to OFF position. Go to step 135) and check A/C high pressure input to PCM. If PID value indicates OPEN, turn ignition switch to OFF position. Reconnect A/C high pressure switch. Check A/C high pressure switch operation and check for overcharged A/C system. See appropriate article in AIR CONDITIONING & HEATING.

82) Cooling Fan Always Runs

Turn all accessories off. Turn ignition switch to ON position. Verify that cooling fan is always on. Turn ignition switch to OFF position. See CCRM LOCATIONS table. Disconnect CCRM connector. Turn ignition switch to ON position. If cooling fan is off, go to step 84). If cooling fan is still on, locate and repair short to power in power to fan circuit (Mustang 3.8L) or go to next step (all other models).

83) Check For Short To Power

Disconnect cooling fan. Using a DVOM, measure voltage between negative battery terminal and LOW FAN PWR and HIGH FAN PWR terminals at cooling fan harness connector. If both voltage measurements are less than one volt, problem is intermittent and cannot be duplicated at this time. If any voltage measurement is one volt or more, locate and repair short to power in applicable FAN PWR circuit. Reconnect all components and recheck system operation.

84) Check Operation Of Primary Fan Circuits

Reconnect all connectors. Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Perform the appropriate test procedure as follows:
1. Low Speed Fan Stops Running (Fan Stops Running On Mustang 3.8L) With CCRM Disconnected
  
  Using scan tool, select LFCA and LFCF PIDs from PID/DATA MONITOR & RECORD menu. Command low speed OFF. LFCA PID should indicate OFF and LFCF PID should indicate NO.
2. Fan Stops Running With CCRM Disconnected
  
  Using scan tool, select HFCA and HFCF PIDs from PID/DATA MONITOR & RECORD menu. Command high speed fan OFF. HFCA PID should indicate OFF and HFCF PID should indicate NO.
If LFCF PID of HFCF PID indicated YES with fan commanded off, a primary circuit fault is detected. Go to step 15) (if HFCF PID was yes) or go to step 20) (if LFCF PID was yes). If LFCF PID of HFCF PID indicated NO with fan commanded off, primary circuits are okay. Replace CCRM. Recheck cooling fan operation.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 84) to step 98) . No test procedures have been omitted.

98) Lack Of Cooling: A/C Not Functioning

Turn ignition switch to OFF position. Disconnect A/C cycling switch. Connect a jumper wire between A/C cycling switch harness connector terminals. Disconnect A/C clutch. Connect a DVOM between power and ground terminals at A/C clutch harness connector. Start engine. Turn A/C on and wait 15 seconds. If voltage is not more than 10.5 volts, go to next step. If voltage is more than 10.5 volts, turn ignition switch to OFF position. Remove jumper wire. Reconnect all connectors. If symptom is poor A/C performance in hot ambient temperature on all except Mustang 3.8L, go to step 145). On all others, check and repair A/C system as necessary.

99) Check ACCS PID Value

Ensure jumper wire is still connected between A/C cycling switch harness connector terminals and A/C is on. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If PID value indicates ON, turn ignition switch to OFF position. Remove jumper wire. Reconnect A/C cycling switch, and go to step 110). If PID value indicates OFF, PCM is not receiving ACCS signal. Go to next step.

100) Check For Voltage To A/C Cycling Pressure Switch

Disconnect A/C cycling switch. Turn ignition switch to ON position. Turn A/C switch on. Using a DVOM, measure voltage between A/C demand switch side of A/C cycling switch harness connector and negative battery terminal. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, EEC-V system is okay. Fault is in A/C system. Check A/C system of cause of voltage loss to A/C cycling switch.

101) Check A/C Cycling Switch Contacts

Turn ignition switch to OFF position. Using a DVOM, measure resistance between A/C cycling switch terminals. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, EEC-V system is okay. Fault is in A/C system. Check A/C cycling switch and for proper refrigerant charge. Repair as necessary.

102) Check For Voltage To A/C High Pressure Switch (ACPSW)

Turn ignition switch to OFF position. Reconnect A/C cycling switch. Disconnect ACPSW. Turn ignition switch to ON position. Turn A/C switch on. Using a DVOM, measure voltage between A/C demand switch terminal at ACPSW harness connector and negative battery terminal. See Fig 5. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open circuit between ACPSW and A/C cycling switch.

Fig 5: Checking ACPSW Circuit Voltage
Courtesy of FORD MOTOR CO.

103) Measure Resistance Of ACPSW High Pressure Contacts

Turn ignition switch to OFF position. Using a DVOM, measure resistance between ACPSW high pressure terminals. See Fig 6. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, check for overcharged A/C system. Service A/C system as necessary. If system charge is okay, replace ACPSW.

Fig 6: Checking ACPSW High Pressure Contact Resistance
Courtesy of FORD MOTOR CO.

104) Check Voltage To PCM On ACCS Circuit

Turn ignition switch to OFF position. Reconnect ACPSW. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Turn A/C switch on. Using a DVOM, measure voltage between PCM harness connector terminal No. 41 and negative battery terminal. If voltage is more than 10.5 volts, replace PCM. If voltage is 10.5 volts or less, repair open circuit between PCM and ACPSW.

NOTE: Disregard DTC P1460 if vehicle is not equipped with A/C.

105) KOEO/KOER DTC P1460: Check ACCS PID
This DTC indicates that a fault occurred in Wide Open Throttle A/C Cut-Out (WAC) circuit. Following are possible causes for this fault:
- A/C On During Self-Test
- Open Or Shorted Circuit
- Faulty CCRM
- Faulty Powertrain Control Module (PCM)
Turn A/C and defroster off. Start engine and allow to idle. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If PID value indicates OFF, go to next step. If PID value indicates ON, go to step 125).

106) Check WAC Circuit & WOT A/C Cutoff Relay In CCRM

Turn ignition switch to OFF position. Disconnect CCRM connector. See CCRM LOCATIONS table. Using a DVOM, measure resistance between terminal No. 22 and 24 at CCRM harness connector. See Fig 4. Resistance should be 130-200 ohms. Using a DVOM, measure resistance between terminal No. 22 and terminals No. 1 through 11, 13, 15 and 21 at CCRM harness connector. Each resistance should be more than 1000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace CCRM. Start engine and turn A/C on for 15 seconds. Turn A/C off and repeat QUICK TEST .

107) WAC Circuit For Short To Power

Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage between terminal No. 22 at CCRM and negative battery terminal. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair WAC circuit short to power. Start engine and turn A/C on for 15 seconds. Turn A/C off and repeat QUICK TEST .

108) Check WAC Circuit For Short To Ground

Turn ignition switch to OFF position. Leave CCRM and PCM disconnected. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between terminal No. 22 at CCRM harness connector and negative battery terminal. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair WAC circuit short to ground. Start engine and turn A/C on for 15 seconds. Turn A/C off and repeat QUICK TEST .

109) Check WAC Circuit Resistance

Turn ignition switch to OFF position. Using a DVOM, measure resistance between PCM harness connector terminal No. 69 (WAC) and terminal No. 22 at CCRM harness connector. If resistance is less than 5 ohms, replace PCM. Start engine and turn A/C on for 15 seconds. Turn A/C off and repeat QUICK TEST . If resistance 5 ohms or more, repair open in WAC circuit. Start engine and turn A/C on for 15 seconds. Turn A/C off and repeat QUICK TEST.

110) Check A/C Voltage To CCRM

Turn ignition switch to OFF position. Disconnect CCRM connector. Turn A/C demand switch on. Using a DVOM, measure voltage between terminal No. 21 at CCRM harness connector and negative battery terminal. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in A/C demand circuit between CCRM and ACCS circuit splice to PCM.

111) Check Circuit Continuity

Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Disconnect A/C clutch connector. Using a DVOM, measure resistance of A/C clutch ground circuit between terminal No. 16 at CCRM harness connector and A/C clutch harness connector. Using a DVOM, measure resistance of A/C clutch PWR circuit between terminal No. 23 at CCRM harness connector and A/C clutch harness connector. If any resistance measurement is 5 ohms or more, repair open circuit. If both resistance measurements are less than 5 ohms, replace CCRM. Verify A/C clutch PWR circuit is not shorted to ground.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 111) to step 115) . No test procedures have been omitted.

115) Continuous Memory DTC P1469: Excessive A/C Compressor Clutch Cycling

This DTC indicates ACCS input to PCM has changed states in less than 8.5 second intervals. Possible causes are:
- A/C system mechanical fault such as low refrigerant charge or damaged A/C cycling switch.
- Intermittent open circuit between A/C cycling pressure switch and PCM terminal No. 41 (ACCS).
Check A/C system for mechanical fault such as low refrigerant charge or damaged A/C cycling switch. See appropriate article in AIR CONDITIONING & HEATING. If fault is indicated, isolate fault and repair as necessary. Clear DTCs. Start engine and turn A/C on for about 2 minutes. Turn engine and A/C off and repeat QUICK TEST . If fault is not indicated, go to next step.

116) Check Circuit Between A/C Cycling Switch & PCM

Turn ignition switch to OFF position. Turn ignition switch to ON position. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. Turn A/C switch on. Check for indication of fault while performing the following:
- Shake and bend ACCS circuit between A/C cycling switch and PCM.
- Lightly tap A/C cycling switch to simulate road shock.
Fault will be indicated by ACCS PID quickly turning on and off. If fault is indicated, isolate and repair as necessary. Clear DTCs. Start engine and turn A/C on for about 2 minutes. Turn engine and A/C off and repeat QUICK TEST . If fault is not indicated, problem is intermittent and cannot be duplicated at this time.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 116) to step 120) . No test procedures have been omitted.

NOTE: DTC P1460 indicates an open or short in Wide Open Throttle A/C Cut-Out (WAC) circuit. Disregard DTC P1460 if vehicle is not equipped with A/C.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 120) to step 124) . No test procedures have been omitted.

120) Continuous Memory DTC P1460: Intermittent WAC Circuit Failure
Turn ignition switch to OFF position. Disconnect A/C cycling switch. Connect a jumper wire between A/C cycling switch harness connector terminals. Turn ignition switch to ON position. On Mustang, turn A/C demand switch on. On Escort, using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command outputs ON (this will engage A/C clutch). On all models, check for indication of fault while performing the following:
- Shake and WAC circuit between CCRM and PCM.
- Lightly tap on CCRM to simulate road shock.
An open circuit or short to power is indicated by A/C clutch clicking on (Mustang) or by A/C clutch clicking off (Escort). On Escort, using scan tool, turn outputs OFF. On all models, check for indication of fault while performing the following:
- Shake and WAC circuit between CCRM and PCM.
- Lightly tap on CCRM to simulate road shock.
A short to ground is indicated by A/C clutch clicking off (Mustang) or by A/C clutch clicking on (Escort). If a fault is located, isolate fault and repair as necessary. Start engine and turn A/C on for 15 seconds. Turn A/C off and repeat QUICK TEST . If fault is not located, fault is intermittent. Remove jumper wire and go to TEST Z, step 1) in SELF-DIAGNOSTICS - EEC-V - GASOLINE article in ENGINE PERFORMANCE and check for intermittent faults.

124) DTC P1464: Check ACCS PID

This DTC indicates ACCS input to PCM was high during self-test. Turn ignition switch to OFF position. Connect scan tool to DLC. Turn ignition switch to ON position. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If PID value indicates ON, go to next step. If PID value indicates OFF, indication is A/C and defrost switch were on during self-test. Turn A/C and defrost switch off. Repeat KOEO ON-DEMAND SELF-TEST or KOER ON-DEMAND SELF-TEST where DTC P1464 was received.

125) ACCS PID On

Turn ignition switch to OFF position. Disconnect A/C cycling switch. Turn ignition switch to ON position. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If PID value indicates ON, go to step 127) (Escort) or next step (Mustang). If PID value indicates OFF, check A/C switch and replace switch as necessary. See appropriate article in AIR CONDITIONING & HEATING. If A/C switch is okay, repair short to power in A/C demand circuit to A/C cycling switch.

126) Check A/C Clutch Circuit For Short To Power

Turn ignition switch to OFF position. Disconnect CCRM connector. CCRM LOCATIONS table. Turn ignition switch to ON position. Using a DVOM, measure voltage between terminal No. 23 at CCRM harness connector and negative battery terminal. See Fig 4. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to power.

127) Check ACCS Circuit For Short To Power

Turn ignition switch to OFF position. On Escort, reconnect CCRM and A/C cycling switch. On all models, Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage at PCM harness connector terminal No. 41 and negative battery terminal. If voltage is less than one volt, replace PCM (Escort) or go to next step (Mustang). If voltage is one volt or more, repair short to power in ACCS circuit.

128) Check ACCS Circuit Voltage To PCM

Turn ignition switch to OFF position. Leave A/C cycling switch and PCM disconnected. Reconnect CCRM. Turn ignition switch to ON position. Using a DVOM, measure voltage between PCM harness connector terminal No. 41 and ground. If voltage is less than one volt, replace PCM. If voltage is one volt or more, replace CCRM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 128) to step 130) . No test procedures have been omitted.

130) Check If A/C Turns Off When A/C Switch Is Turned Off

Turn A/C demand switch off. If A/C turns off, go to next step. If A/C does not turn off, go to step 140).

131) Check If A/C Cuts Off During WOT

Start engine and allow to idle. Turn A/C on. Briefly snap throttle wide open and then return to idle. Listen for A/C clutch disengagement during WOT, then re-engagement after a few seconds of returning to idle. A click noise will be heard when A/C re-engages. Repeat test several times. If A/C clicking noise cannot be heard, disconnect A/C clutch. Connect a test light between A/C clutch power and ground terminals at A/C clutch harness connector. Again, briefly snap throttle to wide open position and return to idle. Test light should be off during WOT and on after a few seconds of returning to idle. If A/C clutch or test light operates as specified, WAC circuit is functioning properly at this time. Go to TEST Z, step 1) SELF-DIAGNOSTICS - EEC-V - GASOLINE article in ENGINE PERFORMANCE and check for intermittents. If A/C clutch or test light does not operate as specified, go to next step.

132) No WOT A/C Cutoff, No DTCs: Check CCRM

Reconnect A/C clutch (if necessary). Turn ignition switch to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Turn A/C DEMAND switch on. While observing A/C clutch engagement, command outputs on and off several times. If A/C clutch engagement cycles, system is functioning properly at this time. Go to TEST Z, step 1) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE article in ENGINE PERFORMANCE and check for intermittent faults. If A/C clutch does not cycle, replace CCRM.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 132) to step 135) . No test procedures have been omitted.

135) Check ACPSW Circuit For Short To Ground

Turn ignition switch to OFF position. Disconnect A/C high pressure switch connector. Disconnect scan tool from Data Link Connector (DLC). Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance between PCM harness connector terminal No. 86 and ground. If resistance is more than 10 k/ohms, replace PCM. If resistance is 10 k/ohms or less, repair short to ground in ACPSW circuit.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 135) to step 140) . No test procedures have been omitted.

140) A/C Always On: Check Voltage At A/C Clutch

Turn ignition switch to OFF position. Turn A/C and defroster off. Disconnect A/C clutch. Connect a DVOM between A/C clutch harness connector terminals. Start engine. If voltage is 2 volts or more, go to next step. If voltage is less than 2 volts, electrical portion of A/C system is not at fault. If A/C related symptom still exists, see appropriate article in AIR CONDITIONING & HEATING.

141) Check ACCS Input To PCM

Turn ignition switch to OFF position. Ensure A/C and defroster are off. Start engine. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If PID value indicates ON, go to step 125). If PID value indicates OFF, check A/C system and repair as necessary. See appropriate article in AIR CONDITIONING & HEATING.
NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 141) to step 145) . No test procedures have been omitted.

145) Check A/C High Pressure Switch Medium Pressure Circuits

Turn ignition switch to OFF position. Disconnect A/C high pressure switch. Ensure A/C is off. Connect jumper wire between ACPSW terminal and ground terminal at A/C high pressure switch connector. See Fig 7. Start engine and allow to idle for 15 seconds. If high speed fan does not come on, go to next step. If high speed fan comes on, turn ignition switch to OFF position. A/C high pressure switch medium pressure circuits are okay. Remove jumper wire and reconnect A/C high pressure switch connector. See appropriate article in AIR CONDITIONING & HEATING to diagnose symptom.

Fig 7: Testing Medium Pressure Circuits At High Pressure Switch
Courtesy of FORD MOTOR CO.

Check Ground Circuit To A/C High Pressure Switch

With engine still running, move jumper wire from ground terminal at A/C high pressure switch connector to negative battery post. Wait 15 seconds. If high speed fan comes on, turn ignition switch to OFF position. Repair open ground circuit to A/C high pressure switch. If high speed fan does not come on, remove jumper wire and go to next step.

Check ACPSW Circuit To PCM

Disconnect PCM connector(s). Using a DVOM, measure resistance between PCM harness connector terminal No. 86 and A/C high pressure switch connector ACPSW terminal. See Fig 7. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open circuit.