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Diagnosis & Repair (Using OBD-II Scan Tool)

  1. Disconnect EGR temperature sensor harness connector. Measure resistance between EGR temperature sensor terminals (component side). If resistance is 600 k/ohms or less, go to next step. If resistance is more than 600 k/ohms, check EGR temperature sensor. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. Replace EGR temperature sensor as necessary.
  2. Turn ignition on. Measure voltage between EGR temperature sensor harness connector terminals. If voltage is 4.5-5.5 volts, go to step  4. If voltage is not 4.5-5.5 volts, go to next step.
  3. Access ECM behind glove box. Using DVOM, backprobe ECM harness connector. On models with California emissions, measure voltage between terminals No. 18 (Blue/Black wire) and No. 19 (Pink wire) at ECM harness connector E6. See Figure. On models without California emissions, measure voltage between terminals No. 9 (Blue/Black wire) and No. 11 (Pink wire) at ECM harness connector E6. See Figure. On all models, turn ignition on. If voltage is 4.5-5.5 volts, repair open in wiring between EGR temperature sensor and ECM. See WIRING DIAGRAMS article. If voltage is not 4.5-5.5 volts, replace ECM.
  4. Check all EGR system vacuum hoses. For proper vacuum hose routing, see appropriate illustration in VACUUM DIAGRAMS article. If problem exists, replace vacuum hoses as necessary. If problem does not exist, go to next step.
  5. Access ECM behind glove box. Ensure ignition is off. Disconnect ECM harness connector E6. See Figure or Figure . Turn ignition on. On models with California emissions, connect a jumper wire between ground and terminal No. 5 (Pink/Black wire) at ECM harness connector E6. On models without California emissions, connect a jumper wire between ground and terminal No. 15 (Pink/Black wire) at ECM harness connector E6. On all models with jumper wire connected, air applied to port "E" of EGR VSV should flow from port "F". See Figure. Disconnect jumper wire. Air applied to port "E" of EGR VSV should not flow from port "F". If EGR VSV operates as specified, go to step  8. If EGR VSV does not operate as specified, go to next step.
  6. Turn ignition off. Disconnect EGR VSV harness connector. Measure resistance between EGR VSV 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 resistances are not as specified, replace EGR VSV. If resistances are as specified, go to next step.
  7. Apply battery voltage and ground to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air should flow from port "F". See Figure. Remove battery voltage from EGR VSV terminals. Air should not flow from port "F". If EGR VSV operates as specified, repair open in wiring between EGR VSV and ECM. If EGR VSV does not operate as specified, replace EGR VSV.
  8. Check EGR system components. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, repair as necessary. If problem does not exist, go to next step.
  9. Check EGR vacuum modulator. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EGR vacuum modulator. If problem does not exist, go to next step.
  10. Check EGR valve. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - 4-CYLINDER article. If problem exists, replace EGR valve. If problem does not exist, go to next step.
  11. Disconnect EGR temperature sensor connector. Start engine. Ensure engine is at normal operating temperature. Run engine at 4000 RPM for 3 minutes and measure resistance between EGR temperature sensor terminals (component side). If resistance is 4300 ohms or less, replace ECM. If resistance is more than 4300 ohms, replace EGR temperature sensor.
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