Intake Manifold Runner Control System Diagnosis

INTAKE MANIFOLD RUNNER CONTROL SYSTEM DIAGNOSIS

CIRCUIT DESCRIPTION
An intake manifold runner control (IMRC) valve is used to change the intake manifold plenum configuration. When the IMRC valve is open, the intake manifold is configured to one large plenum. When the IMRC valve is closed, the intake manifold is configured to 2 smaller plenums. The IMRC valve improves engine performance at low and high engine speeds.

Ignition voltage is supplied to the IMRC solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

The ignition voltage circuit and the IMRC control circuit are routed to the IMRC solenoid through an IMRC driver module. The IMRC driver module is an amplifier that is used to strengthen the IMRC solenoid's ability to remain in the commanded position during high load and current demands.

DIAGNOSTIC AIDS
- Inspect the IMRC solenoid valve for witness marks that indicate that the valve was hitting the intake manifold. This condition may be temperature related.
- A condition with the IMRC driver module, the wiring from the module to the IMRC solenoid, or the solenoid itself will not set a DTC.

TEST DESCRIPTION

Step 1 - Step 9:

The numbers below refer to the step numbers on the diagnostic table.
2. This diagnostic table will only diagnose the IMRC solenoid and the IMRC driver module. If there is a DTC set for the IMRC solenoid, refer to the appropriate DTC table.
5. This step tests the IMRC driver module. The test lamp should turn ON and OFF when commanded with a scan tool. If the test lamp does not turn ON and OFF and there are no IMRC DTCs stored, replace the IMRC driver module.