Pinpoint Test Ah: DTC U0100 - Lost Communication With ECM/Pcm

AH1 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND INSTRUMENT CLUSTER (IC) SELF-TESTS
- Check for recorded instrument cluster (IC) DTCs from the continuous and on-demand self-tests.
- Is DTC B1318 recorded?
1. YES : REFER to DTC Charts .
2. NO : Go to AH2.
AH2 RECHECK THE INSTRUMENT CLUSTER (IC) DTCs
- Repeat the instrument cluster (IC) self-test.
- Clear the DTCs.
- Is DTC U0100 still present?
1. YES : Go to AH3.
2. NO : The system is operating correctly at this time. The DTC may have been set due to high network traffic.
AH3 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND TCM AND ABS MODULE SELF-TESTS
- Check for recorded TCM and ABS module DTCs from the continuous and on-demand self-tests.
- Is DTC U0100 recorded?
1. YES : Go to AH4.
2. NO : Go to AH5.
AH4 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS article. TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
AH5 CHECK FOR CORRECT INSTRUMENT CLUSTER (IC) OPERATION
- Disconnect all the instrument cluster (IC) connectors.
- Check for:
  - corrosion
  - damaged pins
  - pushed-out pins
- Connect all the instrument cluster (IC) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
1. YES : INSTALL a new instrument cluster (IC). REFER to Instrument Cluster (IC) . TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.