Many malfunctions in the electrical system are caused by poor harness and terminals. 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 go to "Verification of Vehicle Repair" procedure
	▶ Go to "Signal Circuit Inspection" procedure.

IG "OFF" and disconnect ECM connector and ABS(ESC) control module connector.

Measure resistance between vehicle speed input signal terminal of ECM harness connector and chassis ground.

Is the measured resistance within specification?

	▶ Go to "Check open in harness" as follows.
	▶ Repair short to ground in harness, and go to "Verification of Vehicle Repair" procedure.

IG "OFF" and disconnect ECM connector and ABS(ESC) control module connector.

Measure resistance between vehicle speed input signal terminal of ECM harness connector and wheel speed sensor output signal terminal of ABS(ESC) control module harness connector.

Is the measured resistance within specification?

	▶ Go to " Check wheel speed sensor " procedure.
	▶ Repair open in harness, and go to "Verification of Vehicle Repair" procedure.

IG "OFF"

Check open or short in wheel speed sensor (Refer to "C1203 Wheel speed sensor front-RH open/short")

Is the wheel speed sensor normal?

	▶ Substitute with a known - good ECM/ ABS(ESC) control unit and check for proper operation. If the problem is corrected, replace ECM/ ABS(ESC) control unit and go to "Verification of Vehicle Repair" procedure.
	▶ Repair or replace it as necessary, and then go to "Verification of Vehicle Repair" procedure. note There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others