Many malfunctions in the electrical system are caused by poor harness(s) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Check the following conditions:
Check for damaged harness and terminals: contact resistance, oxidation, bent or broken terminals.
Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection
Use a suitable male pin to ensure that contact in sockets is good. The pin should remain in position when pulled gently.
Has a problem been found?
YES
Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
Fault is intermittent caused by poor contact in the sensor’s and/or TCM’s connector or was repaired and TCM memory was not cleared.
System OK
Disconnect TCM connector and Turn ignition switch to ON
Measure CAN high circuit waveform between terminal 3/C24-3 of the TCM harness connector and chassis ground
Measure CAN low circuit waveform between terminal 4/C24-3 of the TCM harness connector and chassis ground
Specification : Refer to reference data
Is waveform display the specified value?
YES
Go to "Component Inspection" procedure
NO
Check for open or short in communication harness and Repair it
If communication harness is OK, Replace ECM
