GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Holden 🢒 2007 🢒 WM Sedan 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P2076, P2077, or P2078

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 provides an overview of each diagnostic category

DTC Descriptor

DTC P2076: Intake Manifold Runner Control (IMRC) Solenoid Performance

DTC P2077: Intake Manifold Runner Control (IMRC) Solenoid Circuit Low Voltage

DTC P2078: Intake Manifold Runner Control (IMRC) Solenoid Circuit High Voltage

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 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 shorted to voltage, shorted to ground or an open/high resistance by monitoring the feedback voltage.

Conditions for Running the DTC

Condition 1

Engine is running.

Conditions for Setting the DTC

The ECM determines the IMRC solenoid is outside the expected operating voltages for more than 4 Seconds.

Action Taken When the DTC Sets

DTC P2076, P2077 and P2078 are type B DTCs.

Conditions for Clearing the MIL/DTC

DTC P2076, P2077 and P2078 are type B DTCs.

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.
    • Inspect the manifold runner for any sign of foreign material or excessive dirt build up.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References

Circuit/System Verification
  1. Command the IMRC solenoid ON and OFF with a scan tool. Feel and listen at the IMRC solenoid to confirm operation.
  2. Observe the scan tool to verify that the solenoid request is present.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the IMRC solenoid.
  2. Ignition ON, test for B+ voltage between the ignition 1 voltage circuit of the IMRC solenoid and a known ground.
    3. ⇒If less than B+, test the ignition 1 voltage circuit of the IMRC solenoid for a short to ground or an open/high resistance.
  3. Ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit of the IMRC solenoid.
  4. Ignition ON, using a scan tool command the IMRC solenoid ON/OFF. The test lamp should pulse ON and OFF.
    5. ⇒If the test lamp remains illuminated all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM.
    ⇒If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
  5. If all circuits/connections test normal, replace the IMRC solenoid.

Repair Instructions

Perform the Diagnostic Repair Verification.

    •  Intake Manifold Runner Control Solenoid Replacement
    •  Engine Control Module Replacement for engine control module replacement, setup and programming.