OBD-II code P0660 indicates that the powertrain control module (PCM) has detected an open circuit in the control circuit for the Intake Manifold Tuning (IMT) valve on Bank 1. The IMT valve is a solenoid-operated device that adjusts intake manifold runner length or flap position to optimize airflow across the RPM range. An open-circuit fault means the PCM is not seeing the expected electrical continuity through the solenoid or its wiring.
The solenoid coil inside the intake manifold tuning valve most commonly fails open internally. This is the single most frequent cause of P0660, particularly on higher-mileage vehicles.
A broken, chafed, or stretched wire in the IMT valve control circuit creates a true open-circuit condition. Heat exposure near the intake manifold makes this circuit especially prone to insulation damage.
The two-pin connector at the IMT valve is exposed to engine bay heat and moisture. Corroded terminals, a pushed-out pin, or a connector that has vibrated loose are common causes.
If the manifold runner shaft, flap, or actuator linkage is carboned-up or jammed, the solenoid may be unable to complete its stroke and the PCM can register a circuit fault.
Although the code is typically reported as an open in the control side, loss of fused battery feed to the solenoid will present identically and should be verified before deeper diagnosis.
Internal failure of the PCM's output driver for the IMT valve is possible but uncommon. It should only be considered after every wiring, connector, and valve-side cause has been ruled out by resistance and voltage measurements.
No. In the vast majority of cases the fault is in the IMT valve solenoid itself, its connector, or its wiring. Replacing the PCM is expensive and almost never resolves P0660 unless the control module has already been independently bench-tested and found defective.
Usually yes, at least for a while. The engine will typically run, but you may notice reduced low-end torque, mild hesitation, and a small drop in fuel economy. The underlying cause should still be repaired because it can affect emissions test readiness and long-term drivability.
It is mounted on or near the intake manifold, often on the side or underside of the lower manifold, and is connected to the runner control flap or actuator shaft by a short linkage. Exact location varies by engine design.
No. Erasing the code only clears the light temporarily; if the open-circuit condition is still present, the code will return as soon as the PCM completes its next monitor cycle.