Many malfunctions in the electrical system are caused by poor harness(es) and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
	▶ Go to "Signal circuit inspection" procedure.

Ignition "OFF" & Engine "OFF".

Disconnect HECU and ECM connector.

Measure resistance between CAN HIGH, LOW terminal of the HECU harness connector and CAN HIGH, LOW terminal terminal of the ECM harness connector.

Is the measured resistance within specifications?

	▶ Go to "Component inspection" procedure.
	▶ Repair open in CAN BUS line between HECU harness connector and ECM harness connector and then go to "Verification of Vehicle Repair" procedure.