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Checking Speed Control Operation

NOTE: Perform this test only if there are no Diagnostic Trouble Codes (DTC).
  1. Turn ignition on. Using scan tool, monitor cruise control switch inputs. While observing display, press brake pedal several times. If scan tool displays PRESSED and RELEASED, go to next step. If scan tool does not display brake switch PRESSED and RELEASED, go to NTC-1: BRAKE SWITCH SENSE .
  2. Turn ignition off. Disconnect cruise control servo. Inspect connectors and terminals for good contact. Clean or repair as necessary. Using a DVOM, measure resistance between ground and cruise control servo connector terminal No. 4 (Black wire). If resistance is 5 ohms or more, repair open ground circuit. Perform TEST VER-4A  under VERIFICATION TESTS. If resistance is less than 5 ohms, go to next step.
  3. Reconnect cruise control servo. Turn ignition on. While observing scan tool, press ON/OFF switch several times. If scan tool does not display ON/OFF switch PRESSED and RELEASED, go to step  14. If scan tool displays PRESSED and RELEASED, inspect wiring and connectors. Repair as necessary. Perform TEST VER-4A  under VERIFICATION TESTS. If wiring and connectors are okay, go to next step.
  4. Using scan tool, monitor Park Neutral Position (PNP) switch inputs. While observing display, shift transmission into Drive. If scan tool does not display PNP switch status as D/R, go to NTC-2: CHECKING PARK/NEUTRAL POSITION (PNP) SWITCH OPERATION . If scan tool displays PNP switch status as D/R, inspect throttle cable and linkage. Repair as necessary. Perform TEST VER-4A  under VERIFICATION TESTS. If throttle cable and linkage are okay, go to next step.
  5. While observing scan tool, press SET switch several times. If scan tool does not display SET switch PRESSED and RELEASED, replace left cruise control switch. Perform TEST VER-4A  under VERIFICATION TESTS. If scan tool displays PRESSED and RELEASED, read Diagnostic Trouble Codes (DTC). If DTC P0500 is set, go to DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL  under DIAGNOSTIC TESTS. If no DTC is set, go to next step.
  6. While observing scan tool, press RESUME switch several times. If scan tool displays RESUME switch PRESSED and RELEASED, go to next step. If scan tool does not display PRESSED and RELEASED, go to step  9.
  7. While observing scan tool, press CANCEL switch several times. If scan tool does not display CANCEL switch PRESSED and RELEASED, replace right cruise control switch. Perform TEST VER-4A  under VERIFICATION TESTS. If scan tool displays CANCEL switch PRESSED and RELEASED, go to next step.
  8. While observing scan tool, press COAST switch. If scan tool does not display COAST switch PRESSED and RELEASED, replace right cruise control switch. Perform TEST VER-4A  under VERIFICATION TESTS. If scan tool displays COAST switch PRESSED and RELEASED, go to next step.
  9. Turn ignition off. Disconnect RESUME/ACCEL switch. Inspect connectors and terminals for good contact. Clean or repair as necessary. Using a DVOM, measure resistance of Black/Light Blue wire between ground and RESUME/ACCEL switch connector. If resistance is 5 ohms or more, repair open in Black/Light Blue wire. Perform TEST VER-4A  under VERIFICATION TESTS. If resistance is less than 5 ohms, go to next step.
  10. Reconnect RESUME/ACCEL switch. Start engine and let idle for one minute. Turn engine off. Turn ignition on (engine off). Using scan tool, actuate cruise control servo solenoids. If throttle does not open and close, go to VACUUM SUPPLY  test under COMPONENT TESTS. Repair as necessary. Perform TEST VER-4A  under VERIFICATION TESTS. If throttle opens and closes, go to next step.
  11. Using scan tool, monitor cruise control output status. Road test vehicle at speed greater than 35 MPH and attempt to set cruise control. If cruise control does not set, cruise control denied status message will indicate reason for cruise control not to set. See SCAN TOOL DENIED STATUS  table. Repair as necessary. If cruise control sets, press continue on scan tool and go to next step.
  12. Turn ignition off. Disconnect both cruise control switches. Using a DVOM, measure resistance of Red/Light Green wire between cruise control ON/OFF switch connector and RESUME/ACCEL switch connector. If resistance is 5 ohms or more, repair open in Red/Light Green wire. Perform TEST VER-4A  under VERIFICATION TESTS. If resistance is less than 5 ohms, go to next step.
  13. Reconnect ON/OFF switch. Connect a jumper wire between RESUME/ACCEL switch connector terminals. Turn ignition on. Using scan tool, read cruise control switch voltage. If voltage is less than one volt, replace right cruise control switch. Perform TEST VER-4A  under VERIFICATION TESTS. If voltage is one volt or more, go to next step.
  14. Turn ignition off. Inspect wiring and connectors. Repair as necessary. Perform TEST VER-4A  under VERIFICATION TESTS. If wiring and connectors are okay, start engine. Using scan tool, read cruise control switch voltage. If reading is 4.2 volts or less, go to step  17. If reading is more than 4.2 volts, go to next step.
  15. Turn engine off. Turn ignition on. Using scan tool, monitor P/N switch inputs. While observing display, shift transmission into Drive. If scan tool does not display P/N switch status as D/R, go to NTC-2: CHECKING PARK/NEUTRAL POSITION (PNP) SWITCH OPERATION . If scan tool displays P/N switch status as D/R, inspect throttle cable and linkage. Repair as necessary. Perform TEST VER-4A  under VERIFICATION TESTS.
  16. Using scan tool, read DTCs. If any vehicle speed signal DTCs are displayed, go to DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL  under DIAGNOSTIC TESTS. Repair as necessary. If no DTCs are displayed, go to step  22.
  17. Using scan tool, monitor P/N switch inputs. While observing display, shift transmission into Drive. If scan tool does not display P/N switch status as D/R, go to NTC-2: CHECKING PARK/NEUTRAL SWITCH OPERATION . If scan tool displays P/N switch status as D/R, inspect throttle cable and linkage for binding or damage. Repair as necessary.
  18. Disconnect ON/OFF switch. Using scan tool, read cruise control switch voltage. If voltage is more than 4.2 volts, replace ON/OFF switch. Perform TEST VER-4A  under VERIFICATION TESTS. If voltage is 4.2 volts or less, go to next step.
  19. Turn ignition on, engine off. Using scan tool, read DTCs. If DTC P0500 is displayed, go to DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL  under DIAGNOSTIC TESTS. Repair as necessary. If DTC P0500 is not displayed, go to next step.
  20. Turn ignition off. Disconnect RESUME/ACCEL switch. Turn ignition on. Using scan tool, read cruise control switch voltage. If voltage reading goes from less than 4.2 volts to more than 4.2 volts, replace RESUME/ACCEL switch. Perform TEST VER-4A  under VERIFICATION TESTS. If voltage is 4.2 volts or less, go to next step.
  21. Start engine and let idle for one minute. Turn engine off. Turn ignition on, engine off. Using scan tool, actuate cruise control servo solenoids. If throttle does not open and close, go to VACUUM SUPPLY  test under COMPONENT TESTS. If throttle opens and closes, go to next step.
  22. At this time cruise control switch and servo functions appear to be operating properly. Using scan tool, monitor cruise control output status. Road test vehicle at speed greater than 35 MPH and attempt to set cruise control. If cruise control does not set, cruise control denied status message will indicate reason for cruise control malfunction. See SCAN TOOL DENIED STATUS  table. Repair as necessary.
Fig 1: Identifying Cruise Control Switches
G00011421Courtesy of DAIMLERCHRYSLER CORPORATION
SCAN TOOL DENIED STATUS

Denied Message Reason
ON/OFF PCM Does Not See An ON Signal From Switch At PCM Terminal No. 41
SPEED Vehicle Speed As Seen By PCM Terminal No. 66 Is Not Greater Than 36 MPH
RPM Engine RPM Is Excessively High
BRAKE Brake Switch Sense Circuit Is Open Indicating That Brakes Are Applied
P/N Park/Neutral Switch Sense Circuit Is Grounded Indicating That Transmission Is In Park Or Neutral
RPM/SPD PCM Senses Excessive Engine RPM For A Given Vehicle Speed
SOL FLT PCM Senses A Servo Solenoid Circuit Trouble Code That Is Maturing Or Set In Memory
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