Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: DO NOT use ECM ground terminals when measuring voltage.

Turn ignition off. Check for normal operation of brake lamps while operating the brake pedal. If brake lights are OK, go to step 4. If problem exists, go to next step.
Disconnect brake lamp switch connector (located on brake pedal bracket). Check voltage between ground and brake light switch connector terminal No. 1 (Red/Yellow wire). If battery voltage exists, go to step 4. If battery voltage is not present. go to next step.
Check the following:
- Fuse No. 2 (10 amp) located left end of dash.
- Fuse block connector connection.
- Open or short in Red/Yellow harness wire between brake light switch and fuse block.
Disconnect ECM harness connector. See Figure. Check continuity between brake light switch connector terminal No. 2 (Red/Green wire) and ECM harness connector terminal No. 40. Continuity should exist. Then, check continuity between ground and brake light switch connector terminal No. 2. Continuity should not exist. Turn ignition on. Measure voltage between ground and brake light switch connector terminal No. 2. Voltage should be less than 0.5 volt. Turn ignition off. If any check is not as specified, go to next step. If all checks are as specified go to step 6.
Check intermediate harness connectors between ECM and brakelight switch for damage and repair or replace as necessary. If connectors are OK, repair open, short to ground or short to battery voltage in Red/Green wire.
No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLESHOOTING - NO CODES article.