Possible Causes

• Wiring, terminals or connectors
• Network communication concern
• GWM
• PCM

Harness Side

Harness Side

1. AW1: CHECK THE COMMUNICATION NETWORK 
   • 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.
   • Do the PCM and the GWM pass the Network Test? 

     Yes	No
     Go to  AW2.	DIAGNOSE the scan tool does not communicate with the PCM or GWM. Refer to Module Communications Network article.

2. AW2: RECHECK THE SASM FOR THE LOST COMMUNICATION DTC 
   • Carry out the SASM self-test.
   • Clear the SASM DTCs.
   • Ignition OFF.
   • Ignition ON, engine OFF.
   • Carry out the SASM self-test.
   • Is DTC U0100:xx still present? 

     Yes	No
     Go to  AW3.	The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

3. AW3: REVIEW THE SASM SELF-TEST FOR VOLTAGE-RELATED DTCS 
   • Review the results from the SASM self-test.
   • Is DTC U3003:1C or U3003:17 present? 

     Yes	No
     For DTC U3003:1C, Go to PINPOINT TEST BD . For DTC U3003:17, Go to PINPOINT TEST BE . For all others, No fault found.	Go to  AW4.

4. AW4: CHECK FOR GWM DTCS 
   • Carry out the GWM self-test.
   • Are any DTCs present? 

     Yes	No
     DIAGNOSE the GWM DTC. Refer to Module Communications Network article.	Go to  AW5.

5. AW5: CHECK FOR PCM DTCS 
   • Carry out the PCM KOEO self-test.
   • Are any DTCs present? 

     Yes	No
     DIAGNOSE the PCM DTC. REFER to applicable Electronic Engine Controls article.	Go to  AW6.

6. AW6: 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 SASM. 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  AW7.	The system is operating correctly at this time. The concern may have been due to incorrect parts replacement procedures or incorrect module configuration.

7. AW7: CHECK FOR COMMUNICATION DTCS IN OTHER MODULES 
   • Ignition ON, engine OFF.
   • Retrieve the continuous memory DTCs.
   • Is DTC U0100:xx set in 1 or more modules in addition to the SASM? 

     Yes	No
     Go to  AW8.	Go to  AW9.

8. AW8: VERIFY PCM OPERATION 
   • Ignition OFF.
9. AW9: VERIFY SASM OPERATION 
   • Ignition OFF.
   • SASM connector disconnected. (C2414)
   • GWM connector disconnected. (C2431)