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 "Signal Circuit Inspection (brake pedal isn't depressed)" procedure.

Signal circuit inspection (brake pedal isn't depressed)

1. Ignition "ON" & Engine "OFF".
2. Don't press the brake pedal.
3. Measure voltage between the terminal "5, 21" of the HECU harness connector and chassis ground.
A. Specification: Brake Switch - Approx. B+
Brake Light Switch - Approx. 0V




4. Is the measured voltage within specifications ?
YES
1) Go to "Signal Circuit Inspection (brake pedal is depressed)" procedure.
NO
1) Check for open or blown 15A STOP, 10A SNSR fuse referring to "Circuit Diagram".
Check for short to battery between the battery terminal (+) and the terminal "5" of the HECU harness connector.
Check for open or short to ground between the battery terminal (+) and the terminal "21" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
If OK, Go to "Component Inspection" Procedure.

Signal circuit inspection (brake pedal is depressed)

1. Ignition "ON" & Engine "OFF".
2. Press the brake pedal.
3. Measure voltage between the terminal "5, 21" of the HECU harness connector and chassis ground.
A. Specification: Brake Switch - Approx. 0V
Brake Light Switch - Approx. B+




4. Is the measured voltage within specifications ?
YES
1) Fault is intermittent caused by open or short harness in brake light switch, faulty brake light switch or was repaired and HECU memory was not cleared. Go to "Verification of Vehicle Repair" procedure.
NO
1) Check for open or short to ground between the battery terminal (+) and the terminal "5" of the HECU harness connector.
Check for short to battery between the battery terminal (+) and the terminal "21" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
If OK, Go to "Component Inspection" Procedure.