Procedure "A"
- Turn ignition off. Loosen and retighten 2 engine ground bolts. See Figure. Disconnect AP sensor harness connector. See Fig 1. Inspect connector for water. If water does not exist, go to next step. If water exists, repair or replace connector and retest system.
- Turn ignition on. Measure voltage between engine ground and AP sensor harness connector terminal No. 3 (Brown/White wire). If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair open or short in Brown/White wire between ECM and AP sensor. Retest system.
- Turn ignition off. Check continuity between engine ground and AP sensor harness connector terminal No. 1 (Orange wire). Also, check circuit for short to voltage. See WIRING DIAGRAMS article. Repair circuit as necessary and retest system. If ground circuit is okay, go to next step.
- Disconnect ECM harness connector. Check continuity of White wire between ECM harness connector terminal No. 64 and AP sensor harness connector terminal No. 2. See Figure. Also, check circuit for short to ground and short to voltage. Repair circuit as necessary and retest system. If circuit is okay, go to next step.
- Reconnect all harness connectors. Remove AP sensor from its bracket and disconnect vacuum hose. Turn ignition on. Measure voltage between engine ground and ECM terminal No. 64 by backprobing. Voltage should be 3.2-4.8 volts. Using a hand vacuum pump, apply 7.87 in. Hg of vacuum to AP sensor. Voltage should be 1.0-1.4 volts less than voltage measured with no vacuum applied. Voltage should decrease as vacuum is applied. See Fig 2. If voltage is as specified, go to next step. If voltage is not as specified, replace AP sensor and retest system.
- No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Courtesy of NISSAN MOTOR CO., U.S.A.
Courtesy of NISSAN MOTOR CO., U.S.A.