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Home › Jeep › 2021 › Cherokee Trailhawk › Repair and Diagnosis › Engine Performance › System › 3.2L - DTCS P054C To P1129 › DTC Troubleshooting › P0615-Starter Control Circuit/Open › Diagnostic Test

Diagnostic Test

  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
    2. For future reference, with the scan tool, run and save a vehicle Scan Report and all related recorded data.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK THE STARTER SOLENOID RELAY 2 CONFIGURATION 
    1. Check the Power Distribution Center layout in the wiring information to determine if the Starter Solenoid Relay 2 is removable or a Printed Circuit Board (PCB) Relay in the PDC.

      What type of relay is the PDC configured with?

      Removable Relay: 

      • Go To  3

      PCB Relay: 

      • Go To  10
  3. CHECK THE STARTER SOLENOID RELAY 2 COIL GROUND FOR A SHORT TO VOLTAGE 
    1. Remove the Starter Solenoid Relay 2 from the PDC.
    2. Using a 12 volt test light connected to ground, probe terminal 86 of the Starter Solenoid Relay 2 connector in the PDC.
    3. Turn the ignition on. Do not crank the engine.
      NOTE:

      The test light should not be illuminated if the engine is not being cranked.

      Is the load test bulb illuminated?

      Yes 

      • Repair the Starter Relay 2 (T752) Control circuit for a short to voltage.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE STARTER SOLENOID RELAY 2 CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    1. Connect the negative lead of a load test tool to the negative side of the Battery or a know good chassis ground.
    2. Connect the positive lead of a load test tool at terminal 86 of the Starter Solenoid Relay 2 connector in the PDC.
    3. Attempt to perform a key crank of the engine while monitoring the load test tool.
      NOTE:

      The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.

    4. Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.
      NOTE:

      Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174938Courtesy of CHRYSLER GROUP, LLC

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  5

      No 

      • Go To  7
  5. CHECK THE PDC GROUND CIRCUITS FOR AN OPEN/HIGH RESISTANCE BY LOAD TESTING THE CIRCUITS AT THE STARTER RELAY 
    1. Remove Starter Relay 2 form the PDC.
    2. Connect the positive lead of the load test tool to the positive side of the Battery.
    3. Connect the negative lead of the load test tool to terminal 85 at the relay connector In the PDC.
    4. The bulb on the load test tool should be illuminated and bright for each ground circuit if there is no resistance in the circuitry.
      NOTE:

      Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174957Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      No 

      • Go To  6
  6. CHECK THE PDC GROUND CIRCUITS FOR AN OPEN/HIGH RESISTANCE BY LOAD TESTING THE CIRCUITS 
    1. Using the wiring information, disconnect the PDC harness connectors to isolate all of the ground circuits connected to the PDC. If the PDC does not have connectors, back probe the ground circuits when testing.
      NOTE:

      There are multiple ground circuits connected to the PDC through multiple connectors. All of the ground circuits must be tested.

    2. Connect the positive lead of the load test tool to the positive side of the Battery.
    3. Connect the negative lead of the load test tool to each ground circuit at the PDC harness connectors.
    4. The bulb on the load test tool should be illuminated and bright for each ground circuit if there is no resistance in the circuitry.
      NOTE:

      Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174957Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright for all ground circuits?

      Yes 

      • Replace the Power Distribution Center (PDC) in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Repair the faulty ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CHECK THE (T752) STARTER RELAY 2 CONTROL CIRCUIT TO CHECK FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the PCM C1 harness connector.
    3. Disconnect the PDC C3 harness connector.
    4. Check for continuity between ground and the Starter Relay 2 (T752) Control circuit at the PDC harness connector.

      Is there continuity between ground and the Starter Relay 2 (T752) Control circuit?

      Yes 

      • Go To  8

      No 

      • Repair the (T752) Starter Relay 2 Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  8. CHECK THE (T752) STARTER RELAY 2 CONTROL CIRCUIT TO CHECK FOR AN OPEN/HIGH RESISTANCE 
    CAUTION:

    Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

    1. If it is necessary to probe a terminal at a PCM harness connector, connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
      NOTE:

      The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.

    2. Measure the resistance of the Starter Relay 2 (T752) Control circuit between the PDC harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  9

      No 

      • Repair the (T752) Starter Relay 2 Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  9. CHECK THE PCM DRIVER FOR THE STARTER RELAY 2 CONTROL CIRCUIT 
    1. Turn the ignition off.
    2. Connect the PDC and PCM harness connectors.
    3. Connect the negative lead of the load test tool to the negative side of the Battery or a good chassis ground.
    4. Back probe and connect the positive lead of the load test tool to the (T752) Starter Relay 2 Control circuit at the PDC connector.
    5. Monitor the test light while attempting to crank/start the engine.
    6. The bulb on the load test tool should be illuminated and bright when the engine is attempting to crank.
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright?

      Yes 

      • Replace the Power Distribution Center in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  15
  10. CHECK THE STARTER RELAY 2 (T752) CONTROL CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Turn the ignition off.
    2. Connect the negative lead of the load test tool to the negative side of the Battery or a good chassis ground.
    3. Using a 12 volt test light back probe the Starter Relay 2 (T752) Control circuit at the PDC connector.
    4. Turn the ignition on. Do not crank the engine.
      NOTE:

      The test light should not be illuminated if the engine is not being cranked.

      Is the load test bulb illuminated and bright?

      Yes 

      • Repair the Starter Relay 2 (T752) Control for a short to voltage.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  11
  11. CHECK THE (T752) STARTER RELAY 2 CONTROL CIRCUIT AND PCM DRIVER FOR THE STARTER RELAY 2 CONTROL CIRCUIT BY LOAD TESTING THE CIRCUIT 
    1. Turn the ignition off.
    2. Connect the negative lead of the load test tool to the negative side of the Battery or a good chassis ground.
    3. Back probe and connect the positive lead of the load test tool to the (T752) Starter Relay 2 Control circuit at the PDC connector.
    4. Monitor the load test light while attempting to crank/start the engine.
      NOTE:

      The bulb on the load test tool should be illuminated and bright when the engine is attempting to crank.

    5. Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.
      NOTE:

      Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  12

      No 

      • Go To  13
  12. CHECK THE PDC GROUND CIRCUITS FOR HIGH RESISTANCE BY LOAD TESTING THE CIRCUITS 
    1. Using the wiring information, disconnect the PDC harness connectors to isolate all of the ground circuits to the PDC. If the PDC does not have connectors, back probe the ground circuits when testing.
      NOTE:

      There are multiple ground circuits connected to the PDC through multiple connectors. All of the ground circuits must be tested.

    2. Connect the positive lead of the load test tool to the positive side of the Battery.
    3. Connect the negative lead of the load test tool to each ground circuit at the PDC harness connectors.
    4. The bulb on the load test tool should be illuminated and bright for each ground circuit if there is no resistance in the circuitry.
      NOTE:

      Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only  if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps.

      NOTE:

      Why perform a Voltage Drop Test?  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 bulb of the load test tool. To do so perform the following:

      1. 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      2. 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      3. 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

      GC0174957Courtesy of CHRYSLER GROUP, LLC
      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      Is the load test bulb illuminated and bright for all ground circuits?

      Yes 

      • Replace the PDC in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Repair the faulty ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  13. CHECK THE (T752) STARTER RELAY 2 CONTROL CIRCUIT TO CHECK FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the PCM C1 harness connector.
    3. Disconnect the PDC C3 harness connector.
    4. Check for continuity between ground and the Starter Relay 2 (T752) Control circuit at the PDC harness connector.

      Is there continuity between ground and the Starter Relay 2 (T752) Control circuit?

      Yes 

      • Go To  14

      No 

      • Repair the (T752) Starter Relay 2 Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  14. CHECK THE (T752) STARTER RELAY 2 CONTROL CIRCUIT TO CHECK FOR AN OPEN/HIGH RESISTANCE 
    CAUTION:

    Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

    1. If it is necessary to probe a terminal at a PCM harness connector, connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
      NOTE:

      The GPEC Diagnostic Adaptor can add up to 1.5 Ohms of resistance to the circuit.

    2. Measure the resistance of the Starter Relay 2 (T752) Control circuit between the PDC harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  15

      No 

      • Repair the (T752) Starter Relay 2 Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  15. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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