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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 26 (Engine Controls - Self-Diagnostics - 2.0L) >> Diagnostic Tests >> DTC P0403: EGR Valve Control Circuit Malfunction >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform DTC confirmation procedure. See DTC CONFIRMATION PROCEDURE  under SELF-DIAGNOSTIC SYSTEM. Check for DTCs during KOEO or KOER self-test. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P0403 is present, go to next step. If DTC P0403 is not present, problem is intermittent. See TROUBLE SHOOTING - NO CODES article.
  2. Turn ignition off. Disconnect EGR valve connector. Check for loose, damaged or corroded connector terminals. Repair as necessary, and go to step  7 . If connector terminals are okay, go to next step.
  3. Turn ignition on. Measure voltage between ground and EGR valve harness connector terminals "C" (Red/Black wire) and "D" (Red/Black wire), individually. If battery voltage is present at both terminals, go to next step. If battery voltage is not present at either terminal, repair open in circuit between EGR valve and main relay. See WIRING DIAGRAMS article. Repair as necessary and go to step  7 .
  4. Measure resistance between EGR valve connector terminals "C" and "E", "C" and "A", "D" and "B", and "D" and "F". See Figure . If resistance between each set of terminals is about 22 ohms go to next step. If resistance between any set of terminals is not about 22 ohms, replace EGR valve and go to step  7 .
  5. Disconnect PCM connector. Check for continuity between ground and EGR valve harness connector terminals "A", "B", "E" and "F", individually. If continuity is not present at all terminal, go to next step. If continuity is present at any terminals, repair short to ground in appropriate circuit. See WIRING DIAGRAMS article. Repair as necessary and go to step  7 .
  6. Check for continuity of Red/Yellow wire between EGR valve harness connector terminals "A" and PCM harness connector terminal No. 72, Pink/Black wire between EGR valve harness connector terminals "B" and PCM harness connector terminal No. 46, Green wire between EGR valve harness connector terminals "W" and PCM harness connector terminal No. 68, and Orange/Black wire between EGR valve harness connector terminals "F" and PCM harness connector terminal No. 56. If continuity is present in all wires, go to next step. If continuity is not present in any wire, repair open in appropriate circuit between EGR valve and PCM. See WIRING DIAGRAMS article. Repair as necessary and go to next step.
  7. Reconnect all connections. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P1409 is present, replace PCM and go to next step. See REMOVAL, OVERHAUL & INSTALLATION article. On vehicles equipped with immobilizer system, reprogram ignition key identification numbers. See COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION. If DTC P1409 is not present, go to next step.
  8. Perform DTC confirmation procedure. See DTC CONFIRMATION PROCEDURE  under SELF-DIAGNOSTIC SYSTEM. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
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