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 all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/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 PCM connector.

IG "ON" and keep the brake taking off.

Measure voltage between Pin No.3(brake switch signal) terminal of brake switch harness connector and chassis ground.

Measure voltage between Pin No.1(brake lamp signal) terminal of brake switch harness connector and chassis ground.

Keep the brake stepping on.

Measure voltage between Pin No.3(brake switch signal) terminal of brake switch harness connector and chassis ground.

Measure voltage between Pin No.1(brake lamp signal) terminal of brake switch harness connector and chassis ground.

Is the measured voltage within specification?

	▶ Carefully re-do this troubleshooting guide steps. ▶ If no problems were found with the circuits or connectors, replace the Brake Switch and go to "Verification of Vehicle Repair" procedure.
	▶ Check the fuse between battery and stop lamp switch. ▶ Repair open or short in power circuit of stop lamp switch and go to "Verification of Vehicle Repair" procedure.