DTC Test No. 76: Stoplight Switch Circuit
NOTE:
Stoplight switch may also be referred to as brake switch.
NOTE:
Circuit is monitored when engine is running. DTC is set when during deceleration when PCM expects stoplight switch signal to be continuously low but the signal is high and count is reset to zero, or during acceleration when PCM expects stoplight switch signal to be high but the signal is low and the count is reset to zero. Possible causes for DTC to set are: defective stoplight switch, defective wiring harness or connectors, or defective PCM.
- Turn ignition on. Using scan tool, read brake switch status (input state test A7). Scan tool should display ON when brake pedal is depressed and OFF when brake pedal is released. If status is not okay, go to next step. If status is okay, failure is intermittent. See INTERMITTENT MALFUNCTION .
- Turn ignition off. Disconnect stoplight switch harness connector. Check continuity between terminals No. 3 (Black wire) and No. 4 (Brown/White wire) at stoplight switch (component side). See Fig 1. Continuity should exist when brake pedal is released and no continuity should exist when brake pedal is depressed. If continuity is as specified, go to next step. If continuity is not as specified, replace stoplight switch.
- Turn ignition on. Measure voltage between ground and terminal No. 4 (Brown/White wire) at stoplight switch harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, go to step 7.
- Turn ignition off. Check continuity between ground and terminal No. 3 (Black wire) at stoplight switch harness connector. If continuity exists, go to next step. If continuity does not exist, go to step 10.
- Inspect stoplight switch connector for damaged wires or terminals. If problem does not exist, go to next step. If problem exists, repair as necessary.
- Connect all disconnected components. Using scan tool, retrieve and record DTCs and freeze frame data. Clear DTCs. Test drive vehicle under conditions when DTC was set. If DTC returns, replace PCM. If DTC does not return, test is complete.
- Turn ignition off. Inspect in-line harness connector B-51 for damaged wires or terminals. In-line harness connector B-51 is located behind left front side of center console. See Figure. Inspect Powertrain Control Module (PCM) connectors for damaged wires or terminals. PCM is located at left front corner of engine compartment, in front of Electronic Automatic Transmission Electronic Control Module (EATX-ECM), near relay box. If problem exists, repair connector(s) as necessary. If problem does not exist, go to next step.
- Connect all disconnected components. Using scan tool, retrieve and record DTCs and freeze frame data. Clear DTCs. Test drive vehicle under conditions when DTC was set. If DTC returns, go to next step. If DTC does not return, test is complete.
- Check wiring between stoplight switch and PCM. If problem exists, repair wiring as necessary. If problem does not exist, replace PCM.
- Inspect junction connector No. 2 for damaged wires or terminals. Junction connector No. 2 is located behind left side in instrument panel. See Figure. If problem exists, repair as necessary. If problem does not exist, go to next step.
- Connect all disconnected components. Using scan tool, retrieve and record DTCs and freeze frame data. Clear DTCs. Test drive vehicle under conditions when DTC was set. If DTC does not return, test is complete. If DTC returns, repair wiring between stoplight switch and ground G202. Ground G202 is located behind left side of instrument panel. See Figure.