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Diagnosis & Repair (Using OBD-II Scan Tool)

  1. Disconnect EGR temperature sensor. EGR temperature sensor is mounted on EGR valve body. Using ohmmeter, measure resistance between sensor terminals. If resistance is 2500 ohms or more, go to next step. If resistance is less than 2500 ohms, replace sensor.
  2. Check for short circuit in wiring harness between EGR temperature sensor and ECM. See appropriate wiring diagram in WIRING DIAGRAMS - 3.4L article. Repair wiring as necessary. If wiring harness is okay, go to next step.
  3. Access ECM behind glove box. Ensure ignition is off. Disconnect ECM E6 connector (A/T models) or E8 connector (M/T models). Turn ignition on. On A/T models, connect a jumper wire between ground and terminal No. 8 (Red/White wire) at ECM E6 connector. On M/T models, connect a jumper wire between ground and terminal No. 18 (Red/White wire) at ECM E8 connector.
  4. On all models, with jumper wire connected EGR Vacuum Switching Valve (VSV) is on. Apply air pressure to EGR VSV port "E". See Figure. Air from port "E" should flow through filter on end of EGR VSV. Disconnect jumper wire. Air from port "E" should flow from port "G". If EGR VSV operates as specified, check EGR valve. See SYSTEM/COMPONENT TESTS - 3.4L article. Replace EGR valve as necessary. If VSV does not operate as specified, go to next step.
  5. Turn ignition off. Remove EGR VSV. Using ohmmeter, measure resistance between valve terminals. Resistance should be 33-39 ohms at 68°F (20°C). Measure resistance between each terminal and body of EGR VSV. Resistance should be infinite. If resistance is not as specified, replace EGR VSV. If resistance is as specified, go to next step.
  6. Check EGR VSV operation. Apply battery voltage to EGR VSV terminals. Apply air pressure to EGR VSV port "E". See Figure. Air from port "E" should flow from small filter on end of EGR VSV. Remove battery voltage from EGR VSV terminals. Air from port "E" should flow from port "G". Replace EGR VSV as necessary. If EGR VSV operates as specified, go to next step.
  7. Check for short circuit in wiring harness between EGR VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS - 3.4L article. Repair wiring as necessary. If wiring harness is okay, replace ECM and retest.
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