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Home >> Suzuki >> 2002 >> Esteem GL, 4D Sedan, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 1.6L >> Diagnostic Tests >> DTC P0401 Or DTC P0402 >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  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 on. Using scan tool, select DATA LIST mode. From DATA LIST verify that engine speed is zero MPH, engine coolant temperature is 176°F (80°C) or more and engine speed is less than 3000 RPM. Using scan tool, clear DTC with CLEAR INFO mode, and go to next step.
  3. With engine at idle speed, on scan tool select MISC TEST menu. From MISC TEST menu, use STEP EGR function to open EGR valve. As EGR valve is opened engine speed should drop. If engine speed does not drop as specified check for clogged EGR valve, EGR passages, or stuck EGR valve. Check for poor ECT sensor and/or TP sensor performance. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If no problem is found, go to next step.
  4. Substitute a known good ECM, and repeat DTC CONFIRMATION TEST  . If DTC resets, go to next step. If DTC does not reset, testing is complete.
  5. Turn ignition off. Disconnect EGR valve 6-pin harness connector. EGR valve is located on intake manifold. Measure resistance between specified EGR valve terminals. See CHECKING EGR VALVE RESISTANCE  table. See Fig 2 . If resistance is as specified, go to next step. If resistance is not as specified, replace EGR valve. After repair, repeat DTC CONFIRMATION TEST  .
    CHECKING EGR VALVE RESISTANCE

    Measure Between Pins No. (1) Specification (Ohms)
    A & B 20-24
    C & B 20-24
    F & E 20-24
    D & E 20-24
    B & Valve Body Infinity
    E & Valve Body Infinity
    (1) Measure resistance at 68°F (20°C).
    6. NOTE: DO NOT use a sharp tool to remove carbon. Be careful not to bend or score EGR valve or rod, or damage valve seat.
  6. Check for and clean any carbon build-up from EGR valve or passages.
  7. Inspect EGR valve, valve seat and valve rod for cracks, bends or other damage. If problem is found, repair or replace as necessary. After repair, repeat DTC CONFIRMATION TEST  . If no problem is found, go to next step.
  8. Substitute a known good ECM, and repeat DTC CONFIRMATION TEST  . If DTC does not reset, testing is complete.
Fig 1: Identifying EGR Valve Harness Connector Terminals
G00163649Courtesy of SUZUKI OF AMERICA CORP.
Fig 2: Testing EGR Valve Assembly
G00163648Courtesy of SUZUKI OF AMERICA CORP.
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