GM Service Manual Online
For 1990-2009 cars only

Circuit Description

If the engine control module (ECM) detects an overrun condition, then fuel injection stops.

Conditions for Setting the DTC

    • 400 RPM or higher
    • Fuel injection stop
    • Fuel pressure feed stop

Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected.

Conditions for Clearing the MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

DTC 0543 can be cleared by using the Clear Info option on the Tech 2 or by using the Diag Clear Switch.

DTC 0543 Overrun Judgement (MIL Not Illuminated)

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Does DTC 0543 set with the ignition ON or with the engine operating?

Go to Step 2

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2

Ask the driver if overrun is caused by gear slip-out, shift error, etc.

Did you complete the action?

Misuse by Owner/Operator

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