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.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
YES
Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
Go to "Signal circuit inspection" procedure.
Ignition "ON" & Engine "OFF".
Press the brake pedal.
Measure voltage between the terminal "5,21" of the HECU harness connector and chassis ground.
Specification : Brake Lamp Switch - Approx. B+
Brake Switch - Approx. 0V
Is the measured voltage within specifications?
YES
Fault is intermittent caused by open harness in brake light switch and brake switch line, faulty brake light switch or was repaired and HECU memory was not cleared. Go to "Verification of Vehicle Repair" procedure.
NO
Check for damaged harness and poor connection in the power harness between the battery terminal(+) and the terminal "5,21" of the HECU harness connector . Check for open or blown 15A STOP fuse referring to "Circuit Diagram" . Repair as necessary and then go to "Verification of vehicle Repair" procedure.
If OK, Go to "Component Inspection" procedure.