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Diagnosis & Repair Procedure

  1. Check for DTC P0107/P0108. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC is not set, go to next step. If DTC is set, go to DTC P0107 OR DTC P0108  .
  2. Perform DTC CONFIRMATION TEST  . If DTC P0401/P0402 is set, go to next step. If DTC P0401/P402 is not set, problem is intermittent. System is okay at this time. See INTERMITTENTS TROUBLE SHOOTING - NO CODES article.
  3. If not using scan tool, go to next step. If using scan tool, turn ignition off. Connect scan tool. Turn ignition on and check EGR system operation. See EXHAUST GAS RECIRCULATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If EGR system is not okay, go to step  5 . If EGR system is okay, problem is intermittent. System is okay at this time. See INTERMITTENTS TROUBLE SHOOTING - NO CODES article. If intermittent problem is not found, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
  4. Turn ignition off. Disconnect EGR valve connector. Turn ignition on. Measure voltage between ground and EGR valve harness connector C04 terminals No. 2 (Blue/Black wire) and No. 5 (Blue/Black wire), individually. If 10-14 volts exist at both terminals, go to next step. If 10-14 volts do not exist at either terminal, check for short or open in suspect Blue/Black wire between EGR valve and main relay. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary and go to DTC CONFIRMATION TEST  .
  5. Turn ignition off. Reconnect EGR valve connector. Disconnect ECM (PCM) 28-pin connector C51-2. Measure resistance between ECM (PCM) 28-pin harness connector C51-2 terminal No. 20 (Blue/Black wire) and terminals No. 4 (Light Green/White wire), No. 5 (Light Green wire), No. 16 (Light Green/Red wire) and No. 17 (Light Green/Yellow wire), individually. See Figure . Resistance at each terminal should be 20-24 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step  7 .
  6. Check for a stuck or faulty EGR valve. Also check for plugged EGR passage in intake manifold. Repair as necessary and go to DTC CONFIRMATION TEST  . If EGR valve and passage are okay, go to step  8 .
  7. Check for open or short in Light Green wire, Light Green/White wire, Light Green/Red wire and Light Green/Yellow wire between EGR valve and ECM (PCM) 28-pin connector C51-2. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary and go to DTC CONFIRMATION TEST  . If wires are okay, check EGR valve operation. See EXHAUST GAS RECIRCULATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. Replace as necessary and go to DTC CONFIRMATION TEST  .
  8. Measure voltage between ECM (PCM) 26-pin harness connector C51-3 terminals No. 13 and No. 20 (or No. 21). See Figure . With ignition ON and engine OFF, reading should be 3.3-4.3 volts. With engine at idle, reading should be less than 3.3 volts. If voltage is as specified, replace ECM (PCM) and go to DTC CONFIRMATION TEST  . If voltage is not as specified, check MAP sensor operation. See DTC P0107 OR DTC P0108  . Repair as necessary and go to DTC CONFIRMATION TEST  .
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