W/Harness Inspection

Terminal and Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
1) Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
1) Go to "Power Circuit Inspection" procedure.

Power Supply Circuit Inspection

1. Ignition "ON".
2. Measure voltage between terminal "1" of the wheel speed sensor (FR) harness connector and chassis ground.
A. Specification : Approx. B+




3. Is the measured voltage within specifications?
YES
1) Go to "Signal Circuit Inspection" procedure.
NO
1) Check for open or short to GND in wheel speed sensor harness (FR) between terminal "1" of the wheel speed sensor (FL) harness connector and terminal "45 (ESC), 19 (ABS)" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
2) If OK, Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.

Signal Circuit Inspection

1. Lift the vehicle.
2. Ignition "ON".
3. Turn the wheel by hand.
4. Measure waveform between terminal "30 (ESC), 20 (ABS)" of the HECU harness connector and chassis ground.
A. Specification : High : 1.18 - 1.68V, Low : 0.59 - 0.84V




5. Is the measured waveform within specifications?
YES
1) Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
NO
1) Check for open or short to GND in wheel speed sensor harness (FL) between terminal "2" of the wheel speed sensor (FR) harness connector and terminal "30 (ESC), 20 (ABS)" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
2) If OK, Go to "Component Inspection" procedure.