Q: Intake manifold runner control stuck

The IMRC (Intake manifold runner control) is a vacuum modulated solenoid that operates a butterfly valve in the intake manifold. The purpose is to optimize the air/fuel ratio for best fuel economy and drivability. Sometimes the code will refer to the IMRC assembly, but the problem lies elsewhere and that means the fault has to be diagnosed to avoid needless part replacement.

For example, the code could set due to broken or restricted vacuum hoses, the IMRC circuit being open, the IMRC circuit shorted to ground or VREF, the SIG RTN circuit open, or unmetered air after the MAF can also set the code for an IMRC fault. Faults with the IMRC itself can be due to the control motor getting disconnected or stuck.

Parts outside the intake should be inspected for movement when commanded. All of the valves are attached to the same rod running from one side of the intake to the other with bushings between runners and those bushings can wear out over time. If you need to have this repaired, a certified technician from YourMechanic can come to your car’s location to diagnose the Check Engine Light and replace the IMRC if necessary.