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?
YES
▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO
▶ Go to " Power Circuit Inspection " procedure.
■ Check voltage
IG "OFF".
Disconnect the PCM connector.
IG "ON" and ENG "OFF"
Brake "OFF" : Measure the voltage between brake lamp signal terminal of PCM harness connector and chassis ground.(Measurement "A")
Brake "ON" : Measure the voltage between brake lamp signal terminal of PCM harness connector and chassis ground.(Measurement "B")
Specification :
Item | Brake "OFF" | Brake "ON" |
Brake Lamp side | 0V | Battery voltage |
Is the measured voltage within specification ?
YES
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
Go to "Check open in harness" as follows.
■ Check open in harness
IG "OFF".
Disconnect the brake switch and PCM connector.
Measure the resistance between brake lamp signal terminal of PCM harness connector and brake lamp signal terminal of Stop lamp switch harness connector.
Specification : Approx. below 1Ω
Is the measured resistance within specification ?
YES
Go to "Check Battery voltage" as follows.
NO
Repair open in harness and go to "Verification of Vehicle Repair" procedure.
■ Check battery voltage
IG Key "OFF".
Disconnect the stop lamp switch connector.
Measure the voltage between power supply terminals of stop lamp switch harness connector and chassis ground.
IG Key "ON".
Measure the voltage between power supply terminals of stop lamp switch harness connector and chassis ground.
Specification :
Item | IG "OFF" | IG "ON" |
Power supply to brake switch side | Battery voltage | Battery voltage |
Power supply to brake lamp side | 0V | Battery voltage |
Is the measured voltage within specification ?
YES
Substitute with a known - good stop lamp switch and check for proper operation.
If the problem is corrected, replace stop lamp switch and go to "Verification of Vehicle Repair" procedure.
NO
Check the fuse between battery and stop lamp switch.
Repair open or short in power harness of stop lamp switch and go to "Verification of Vehicle Repair" procedure.
