For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provide an overview of each diagnostic category.

### Circuit/System 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 directly 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 IMRC valve also contains a position sensor which is used to detect the actual position of the IMRC valve in relation to its commanded position. The ECM supplies the IMRC position sensor with a 5-volt signal circuit and the position sensor uses a common ground circuit. The position sensor enables the ECM to detect a physically broken or stuck IMRC valve.

### 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.

• | If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool circuit test status parameters for the component. A circuit test status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

### Circuit/System Verification

Ignition ON, observe the scan tool DTC information. Verify that DTCs P2008, P2009, P2010, P2076, P2077, or P2078 is not set.

⇒ | If any of the DTCs listed are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

### Circuit/System Testing

1. Ignition OFF, remove the intake manifold runner control (IMRC) solenoid from the intake manifold, with the electrical connector connected.
2. Ignition ON, command the IMRC solenoid ON and OFF with a scan tool. Verify that the IMRC solenoid operates in both directions.

⇒ | If the IMRC solenoid does not operate in both directions, replace the IMRC solenoid.

3. Inspect the inside of the intake manifold for the following conditions:

• | Carbon build-up that limits the movement of the IMRC valve

• | Casting flash that limits the movement of the IMRC valve

• | Foreign material that limits the movement of the IMRC valve

⇒ | If a condition is found, repair as necessary.

4. Clean or replace the upper intake manifold.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Intake Manifold Runner Control Solenoid Replacement

• | Upper Intake Manifold Replacement