LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2004 >> Vitara 4WD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0403: EGR Flow Circuit Malfunction >> Diagnosis & Repair Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Suzuki XL-7. However, it is still accessible from the selected car via links, so may be relevant.
  1. If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK  under SYSTEM TESTS.
  2. Turn ignition off and disconnect EGR valve 6-pin harness connector. EGR valve is located on intake manifold. Check for poor terminal contact at EGR valve harness connector. If poor terminal contact is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If terminal contact is okay, go to next step.
  3. Check EGR valve resistance. See EXHAUST GAS RECIRCULATION under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If problem is found, replace EGR valve as necessary. After repair, repeat DTC CONFIRMATION TEST . If EGR valve tests okay, go to next step.
  4. Turn ignition off. Reconnect EGR valve harness connector. Disconnect ECM 26-pin harness connector C51-3 and ECM 30-pin hanress connector C51-2. ECM is located under instrument panel, behind glove box. See Figure. Check for poor terminal contact at ECM harness connectors. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem with wiring is found, go to next step.
  5. Measure resistance between ECM harness connector C51-3 terminal No. 4 (Blue/Black wire) and ECM harness connector C51-2 terminals as follows:
    • No. 12 (Light Green/Red wire).
    • No. 13 (Light Green/Yellow wire).
    • No. 14 (Light Green/White wire).
    • No. 15 (Light Green wire).
    Resistance at each terminal should be 20-24 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified at any terminal, repair open or short in suspect wire between ECM and EGR. See WIRING DIAGRAMS article. After repair, repeat DTC CONFIRMATION TEST .
  6. Check for continuity between ground and ECM harness connector C51-2 terminals as follows:
    • No. 12 (Light Green/Red wire).
    • No. 13 (Light Green/Yellow wire).
    • No. 14 (Light Green/White wire).
    • No. 15 (Light Green wire).
    See Figure. If continuity is present at any terminal, check for a short to ground in suspect wire between ECM and EGR. See WIRING DIAGRAMS article. After repair, repeat DTC CONFIRMATION TEST . If no continuity exists and resistance was as specified as tested in previous test, problem is probably intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. If intermittent problem is not found, substitute a known good ECM and repeat DTC CONFIRMATION TEST . If DTC does not reset, testing is complete.
scientia non olet · About LEMON Manuals