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Home › Infiniti › 2000 › QX4 › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0105: Absolute Pressure (AP) Sensor › Procedure "B"

Procedure "B"

  1. Warm engine to normal operating temperature. Turn ignition off. Connect a vacuum gauge using a vacuum "T" to AP sensor hose. While monitoring vacuum gauge, start engine and let it idle. Vacuum should not exist for 5 seconds. Manifold vacuum should exist after 5 seconds. If vacuum is as specified, go to step  3. If manifold vacuum is not as specified, go to next step.
  2. Check vacuum supply to MAP/BARO solenoid. Repair as necessary. If vacuum supply is okay, check MAP/BARO solenoid. See DTC P1105: MANIFOLD ABSOLUTE PRESSURE (MAP)/BAROMETRIC PRESSURE (BARO) SOLENOID . Replace MAP/BARO solenoid, if necessary. If MAP/BARO solenoid is okay, check intake system for air leaks. Repair as necessary.
  3. Turn ignition off. Inspect vacuum hose between AP sensor and MAP/BARO solenoid for clogging or leaks. Repair as necessary. If vacuum hose is okay, inspect AP sensor harness connector for water. Repair or replace, if necessary. If connector is okay, go to next step.
  4. Remove AP sensor from its bracket and disconnect vacuum hose. Turn ignition on. Measure voltage between ECM harness connector terminal No. 45 and ground 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 Figure. If voltage is not as specified, replace AP sensor. If voltage is as specified, go to next step.
  5. No problem is currently indicated. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
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