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.

CHECK FOR SYSTEM VOLTAGE DTCS IN ALL MODULES
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 .

Repair any Low or High Voltage DTCs in HCP, BPCM, PCM, or IDCM before proceeding and recheck operation.
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.
  Are there any system voltage high or low DTCs present in any modules?
  
  Yes
  - Diagnose and repair the low voltage system or battery issue. Erase DTCs and retest.
  - Perform the BATTERY PACK CONTROL MODULE (BPCM) VERIFICATION TEST. Refer to HV VERIFICATION TEST .
  No
  - Go To 2
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 3
  No
  - Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION and/or BPCM INTERMITTENT CONDITION .
CHECK FOR CONTACTOR CONTROL AND HVIL DTCS
1. Refer to the recorded DTCs and scan report.
  Are there any Contactor Control or HVIL DTCs active?
  
  Yes
  - Perform the appropriate diagnostic test.
  - Perform the BATTERY PACK CONTROL MODULE (BPCM) VERIFICATION TEST. Refer to HV VERIFICATION TEST .
  No
  - Go To 4
ISOLATE AND CHECK THE (H493), (H494), (H393) AND (H394) CONTACTOR CONTROL CIRCUITS FOR A SHORT TO ANOTHER CIRCUIT AT THE HV BATTERY PACK C8 HARNESS CONNECTOR
1. The ignition must be off when performing a resistance check to find a short between circuits.
2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note: Use the wiring diagram as a guide to follow the path of the circuit.
3. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
  NOTE:
  When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.
  
  NOTE:
  With the circuit isolated there should be no continuity between the circuit being tested and any other circuit.
  
  Is there continuity between the circuit being tested and any other circuit?
  
  Yes
  - Repair the short between the circuits that have 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 BATTERY PACK CONTROL MODULE (BPCM) VERIFICATION TEST. Refer to HV VERIFICATION TEST .
  No
  - Go To 5
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all BPCM harness connectors.
2. Disconnect all BPCM low voltage bridge harness connectors.
3. Disconnect all HV bridge harness connectors.
4. Disconnect all related in-line harness connections (if equipped).
5. Disconnect the related component harness connectors.
6. 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.
  - Short in LV harness to the BPCM.
  Repair any conditions that are found.
7. Reconnect all BPCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
10. With the scan tool, erase DTCs.
11. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
12. With the scan tool, read BPCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Primary and Secondary High Voltage Battery Packs in accordance with the Service Information. Refer to HIGH VOLTAGE BATTERY, REMOVAL AND INSTALLATION .
  - Perform the BATTERY PACK CONTROL MODULE (BPCM) VERIFICATION TEST. Refer to HV VERIFICATION TEST .
  No
  - Perform the BATTERY PACK CONTROL MODULE (BPCM) VERIFICATION TEST. Refer to HV VERIFICATION TEST .
  - Test complete.