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Home >> Jeep >> 2025 >> Compass Trailhawk >> Repair and Diagnosis >> Engine Performance >> System >> 2.0L - DTCS P2461 To P2AB9 >> DTC Troubleshooting >> P26E4 Starter Control 2 Circuit >> 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 RELAY 1 CONFIGURATION 
    1. Check the Power Distribution Center layout in the wiring information to determine if the Starter Relay 1 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  11
  3. CHECK THE STARTER RELAY 1 AND PDC FOR PROPER OPERATION 
    1. Turn the ignition on.
    2. Using a 12-volt test light connected to ground back probe the Starter Relay 1 (K90) Control circuit at the PDC C3 connector.
      NOTE:

      The relay should make an audible click when closing. Another way to verify that the relay closed is to check for voltage on the relay output circuit. 

      Does the Starter Relay 1 close when the control circuit is grounded?

      Yes 

      • Go To  4

      No 

      • Go To  8
  4. ISOLATE AND CHECK THE STARTER RELAY 1 (K90) CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE BCM HARNESS CONNECTOR 
    1. Turn the ignition off.
    2. Disconnect the BCM C4 harness connector.
    3. Disconnect the PDC C3 harness connector.
    4. Check for continuity between the Starter Relay 1 (K90) Control circuit and all other circuits at the BCM C4 harness connector.

      Is there continuity between the Starter Relay 1 (K90) Control circuit and any other circuit?

      Yes 

      • Repair the short to the circuit that showed continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE STARTER RELAY 1 (K90) CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Check for continuity between ground and the Starter Relay 1 (K90) Control circuit at the BCM C4 harness connector.

      Is there continuity between ground and the Starter Relay 1 (K90) Control circuit?

      Yes 

      • Repair the Starter Relay 1 (K90) Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK THE STARTER RELAY 1 (K90) CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the Starter Relay 1 (K90) Control circuit between the PDC C3 harness connector and the BCM C4 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the Starter Relay 1 (K90) Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .
  7. CHECK RELATED BCM AND COMPONENT CONNECTIONS 
    1. Disconnect all BCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. 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.

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

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  8. CHECK THE STARTER RELAY 1 COIL VOLTAGE SUPPLY AT THE STARTER RELAY 1 CONNECTOR IN THE PDC 
    1. Turn the ignition off.
    2. Remove the Starter Relay 1 from the PDC.
    3. Turn the ignition on.
    4. Measure the voltage at terminal 86 of the relay connector in the PDC.
      NOTE:

      If the voltage supply is coming from the output of another relay, verify that the other relay is energized. 

      Does the terminal have Battery voltage present?

      Yes 

      • Go To  9

      No 

      • Go To  10
  9. CHECK THE STARTER RELAY 1 CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE IN THE PDC 
    1. Disconnect the PDC C3 Connector.
    2. Measure the resistance of the Starter Relay 1 Control circuit between terminal 85 of the relay connector in the PDC and terminal of the PDC C3 connector (component side).

      Is the resistance below 3.0 Ohms?

      Yes 

      No 

  10. CHECK THE BATTERY SUPPLY VOLTAGE TO THE PDC 
    1. Using the wiring information as a guide, measure the main Battery voltage supply at the PDC terminal.

      Is Battery voltage present?

      Yes 

      No 

      • Repair the Battery voltage supply to the PDC for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .
  11. CHECK THE STARTER RELAY 1 AND PDC FOR PROPER OPERATION 
    1. Turn the ignition on.
    2. Using a 12-volt test light connected to ground, back probe the Starter Relay 1 (K90) Control circuit at the PDC C3 connector.
      NOTE:

      The relay should make an audible click when closing. Another way to verify that the relay closed is to check for voltage on the relay output circuit. 

      Does the Starter Relay 1 close when the control circuit is grounded?

      Yes 

      • Go To  12

      No 

      • Go To  16
  12. ISOLATE AND CHECK THE STARTER RELAY 1 (K90) CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE BCM HARNESS CONNECTOR 
    1. Turn the ignition off.
    2. Disconnect the BCM C4 harness connector.
    3. Disconnect the PDC C3 harness connector.
    4. Check for continuity between the Starter Relay 1 (K90) Control circuit and all other circuits at the BCM C4 harness connector.

      Is there continuity between the Starter Relay 1 (K90) Control circuit and any other circuit?

      Yes 

      • Repair the short to the circuit that showed continuity. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  13
  13. CHECK THE STARTER RELAY 1 (K90) CONTROL CIRCUIT FOR A SHORT TO GROUND 
    1. Check for continuity between ground and the Starter Relay 1 (K90) Control circuit at the BCM C4 harness connector.

      Is there continuity between ground and the Starter Relay 1 (K90) Control circuit?

      Yes 

      • Repair the Starter Relay 1 (K90) Control circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  14
  14. CHECK THE STARTER RELAY 1 (K90) CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the Starter Relay 1 (K90) Control circuit between the PDC C3 harness connector and the BCM C4 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  15

      No 

      • Repair the Starter Relay 1 (K90) Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .
  15. CHECK RELATED BCM AND COMPONENT CONNECTIONS 
    1. Disconnect all BCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. 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.

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

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  16. CHECK THE BATTERY SUPPLY VOLTAGE TO THE PDC 
    1. Using the wiring information as a guide, measure the main Battery supply voltage at the PDC terminal.

      Is Battery voltage present?

      Yes 

      • Check all fuses in the PDC. If a fuse is found to be open, replace the and retest. If no problems are found with the fuses, 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 Battery voltage supply to the PDC for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to: POWERTRAIN VERIFICATION TEST .