Diagnostic Procedure "B"
WARNING: This page is about a different car, the 2002 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.
- Start engine and warm to normal operating temperature. Turn ignition off. Connect a vacuum gauge using a vacuum "T" to vacuum hose between AP sensor and MAP/BARO solenoid. While observing vacuum gauge, start engine and let it idle. Vacuum should not exist for 5 seconds after starting engine. Vacuum should exist after engine has been running for 5 seconds. If vacuum is as specified, go to step 5. If vacuum is not as specified, go to next step.
- Turn ignition off. Check vacuum hose for clogging, cracks, disconnection or improper connection. Repair or replace vacuum hose as necessary and retest system. If vacuum hose is okay, check vacuum port in intake manifold for clogging. Clean or repair vacuum port as necessary. If vacuum port is okay, go to next step.
- Remove MAP/BARO solenoid. See Fig 1. Using fused jumper wires, apply battery voltage between MAP/BARO solenoid terminals. See Fig 2. Ensure air flows between ports "A" and "B" and does not flow between ports "A" and "C". Remove jumper wires. Ensure air does not flow between ports "A" and "B" and flows between ports "A" and "C". If air does not flow as specified or operation takes more than one second, replace MAP/BARO solenoid and retest system. If air flows is as specified, go to next step.
- Check air intake system for leaks. Repair intake system as necessary and retest system. If no leaks are found, go to step 8.
- Turn ignition off. Check hose between AP sensor and MAP/BARO solenoid for clogging, cracks, disconnection or improper connection. Repair or replace hose as necessary and retest system. If hose is okay, go to next step.
- Disconnect AP sensor harness connector. See Figure. Inspect AP sensor harness connector for water. If water exists, repair or replace connector as necessary and retest system. If water does not exist, go to next step.
- Remove AP sensor with its harness connector connected. Connect all disconnected harness connectors. Turn ignition on. Measure voltage between ground and AP sensor signal circuit at ECM terminal No. 45 (Pink wire) by backprobing. See Figure and Figure . 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. 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.
CAUTION:
DO NOT use ECM ground terminals when measuring voltage.