Diagnostic Procedure
WARNING: This page is about a different car, the 2003 Infiniti G35. 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. Damage to ECM transistor may result. Use engine ground.
For component location, see COMPONENT LOCATIONS . For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit diagram, see Fig 1 . For ECM pin voltage reference values, see Fig 2 .
- Loosen and retighten 2 engine ground screws. See Figure . Then, go to next step.
- Disconnect EVAP control system pressure sensor harness connector B202. Check sensor harness connector for water. Water should not exist. If water does not exist, go to next step. If water exists, repair or replace harness connector.
- Turn ignition on. Measure voltage between engine ground and EVAP control system pressure sensor harness connector B202 terminal No. 3. If voltage is about 5 volts, go to step 5 . If voltage is not about 5 volts, go to next step.
- Check the following:
- Harness connectors B1 and M12.
- Harness connectors B108 and B201.
- Harness connectors F102 and M72.
- Joint connector-4.
- Harness for open or short between EVAP control system pressure sensor and ECM.
- Turn ignition off. Check harness continuity between engine ground and EVAP control system pressure sensor harness connector B202 terminal No. 1. Continuity should exist. Also check harness for short to ground and short to power. If a problem is found, go to next step. If no problem is found, go to step 7 .
- Check the following:
- Harness connectors B1 and M12.
- Harness connectors B108 and B201.
- Harness connectors F102 and M72.
- Joint connector-3.
- Harness for open or short between EVAP control system pressure sensor and ECM.
- Disconnect ECM harness connector F101. Check harness continuity between ECM harness connector F101 terminal No. 60 and EVAP control system pressure sensor harness connector B202 terminal No. 2. Continuity should exist. Also check harness for short to ground and short to power. If a problem is found, go to next step. If no problem is found, go to step 9 .
- Check the following:
- Harness connectors B1 and M12.
- Harness connectors B108 and B201.
- Harness connectors F102 and M72.
- Harness for open or short between EVAP control system pressure sensor and ECM.
- Remove EVAP control system pressure sensor with harness connector connected. Remove hose from EVAP control system pressure sensor. Install a vacuum pump to EVAP control system pressure sensor. Turn ignition on. Use pump to apply vacuum and pressure to EVAP control system pressure sensor. Measure voltage between engine ground and ECM terminal No. 60 by backprobing. Voltage should be 1.8-4.8 volts with no vacuum applied. Using a hand vacuum pump, apply -7.87 in. Hg (-26.65 kPa) of vacuum to pressure sensor. Voltage should be 2.1-2.5 volts less than voltage measured with no vacuum applied. Voltage should decrease as vacuum is applied. If voltage is as specified, go to next step. If voltage is not as specified, replace EVAP control system pressure sensor.
- No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
CAUTION:
Always calibrate the vacuum pump prior to using it. DO NOT apply less than -27.56 in. Hg (-93.3 kPa) or more than 29.91 in. Hg (101.3 kPa) of vacuum to EVAP control system pressure sensor.