Possible Causes
- Network communication concern
- GWM
- PCM
- AI1: CHECK THE PCM COMMUNICATION
- Ignition ON, engine OFF.
- Press the Read Vehicle Information button to view the results of the modules communicating on the network.
- Retrieve the continuous memory DTCs.
- Does the PCM pass the Network Test?
Yes No RETRIEVE and RECORD all PCM DTCs. REFER to the appropriate Electronic Engine Controls article or the Engine Controls article. If there are no DTCs in the PCM, Go to AI3. Go to AI2.
- AI2: CHECK THE GWM COMMUNICATION
- Review the results of the modules communicating on the network from the previous step.
- Did the GWM pass the Network Test?
Yes No DIAGNOSE the PCM does not communicate with the diagnostic scan tool. REFER to the Module Communications Network article. DIAGNOSE the scan tool does not communicate with the GWM. REFER to the Module Communications Network article.
- AI3: RECHECK THE ABS MODULE FOR THE LOST COMMUNICATION DTC
- AI4: REVIEW THE ABS MODULE SELF-TEST FOR VOLTAGE-REALTED DTCS
- Review the results from the ABS module self-test.
- Is DTC U3003:16 or U3003:17 present?
Yes No For DTC U3003:16, GO to PINPOINT TEST A .
For DTC U3003:17, GO to PINPOINT TEST F .Go to AI5.
- AI5: CHECK FOR GWM DTCS
Carry out the GWM self-test.
- Are any DTCs present?
Yes No DIAGNOSE the GWM DTC. REFER to the Module Communications Network article. Go to AI6.
- Are any DTCs present?
- AI6: CHECK FOR PCM DTCS
Carry out the PCM KOEO self-test.
- Are any DTCs present?
Yes No DIAGNOSE the PCM DTC. REFER to the appropriate Electronic Engine Controls article. Go to AI7.
- Are any DTCs present?
- AI7: CHECK FOR OTHER CAUSES OF COMMUNICATION NETWORK CONCERN NOTE: If new modules were installed prior to the DTC being set, the module configuration can be incorrectly set during the PMI or the PMI may not have been carried out.
- Check the vehicle service history for recent service actions related to the PCM or the ABS module. If recent service history is found:
- Verify the correct replacement module was installed. HVBOM may be used to verify correct part fitment.
- Verify the configuration of replacement module was correct. Re-configure the module using as-built data if prior configuration is suspect.
- Verify the module was not obtained from a like vehicle and installed into customer vehicle. Return the swapped module to source vehicle and obtain new replacement module.
- Operate the system and determine if the observable symptom is still present.
- Is the observable symptom still present?
Yes No Go to AI8. The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.
- Check the vehicle service history for recent service actions related to the PCM or the ABS module. If recent service history is found:
- AI8: CHECK FOR COMMUNICATION DTCS IN OTHER MODULES
- Ignition ON, engine OFF.
- Retrieve the continuous memory DTCs.
- Is any DTC from the Fault Trigger Conditions Table set in 1 or more modules in addition to the ABS module?
- AI9: VERIFY PCM OPERATION
- AI10: VERIFY ABS MODULE OPERATION
- Ignition OFF.
- ABS Module connector disconnected. (C155)
- GWM connector disconnected. (C2431)
- AI11: VERIFY ABS OPERATION
- Ignition OFF.
- ABS_A Module connector disconnected. (C135A)
- ABS_B Module connector disconnected. (C135B)
- GWM connector disconnected. (C2431)