Diagnostic Test

WARNING: This page is about a different car, the 2025 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR DTC TO RETURN
WARNING:
On vehicles equipped with the high voltage system, you must thoroughly read and follow all High Voltage Safety procedures. In addition, before performing any diagnostic or service procedure near a high voltage component, you must perform the High Voltage Power Down. Failure to follow these instructions may result in possible serious or fatal injury.

Read the HIGH-VOLTAGE SAFETY PROCEDURES. Refer to HIGH VOLTAGE SAFETY PROCEDURES .

When the HIGH-VOLTAGE POWER-DOWN PROCEDURE is necessary. Refer to HIGH VOLTAGE POWER DOWN .
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 Next Step.
  No
  - Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK FOR COOLING SYSTEM AND A/C SYSTEM PROBLEMS
1. Check the High Voltage Battery Cooling System Loop for problems that could cause the overheating condition.
2. Check the High Voltage Battery Chiller and associated A/C System for problems that could cause the overheating condition.
3. Refer to the recorded DTCs. If any Cooling System or A/C DTCs are set in the BPCM, HCP for Cooling fan and Hybrid/EV Battery Pack coolant DTCs, repair those DTCs. Refer to the appropriate Diagnostic Information.
  Were any Cooling System or A/C System problems found?
  
  Yes
  - Repair the Cooling System or A/C System in accordance with the Service Information.
  - Perform the Hybrid Control Processor (HCP) VERIFICATION TEST. Refer to HYBRID CONTROL PROCESSOR (HCP) VERIFICATION TEST .
  No
  - Go To Next Step.
CHECK TRANSMISSION COMPONENTS
1. Check the Transmission cooler fluid valve and verify that the valve is not stuck or damaged.
2. Check the Transmission Auxiliary pump fuse is the correct value (15A) and not blown.
3. Check the Transmission Lines for leaks, blockage, and correct Transmission pressures.
  Were any problems found?
  
  Yes
  - Repair the Transmission system in accordance with the Service Information.
  - Perform the Hybrid Control Processor (HCP) VERIFICATION TEST. Refer to HYBRID CONTROL PROCESSOR (HCP) VERIFICATION TEST .
  No
  - Go To Next Step.
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all Battery Pack Control Module (BPCM) 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.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all BPCM 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. Using the recorded data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read HCP DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Battery Pack Control Module (BPCM) in accordance with the Service Information. Refer to MODULES, HIGH VOLTAGE SYSTEM, REMOVAL AND INSTALLATION .
  - Perform the Hybrid Control Processor (HCP) VERIFICATION TEST. Refer to HYBRID CONTROL PROCESSOR (HCP) VERIFICATION TEST .
  No
  - Perform the Hybrid Control Processor (HCP) VERIFICATION TEST. Refer to HYBRID CONTROL PROCESSOR (HCP) VERIFICATION TEST .
  - Test complete.