DTC P0660: Intake Manifold Tuning Valve Control Circuit Malfunction: Description

The intake air duct is divided into 2 separate runners connecting to the Intake Manifold Tuning (IMT) valve plenum. The IMT valve plenum is an H type configuration containing the IMT valve assembly. During low speed, high load conditions the IMT valve is closed creating 2 separate runner pats in the incoming air ducts which aids an increasing torque. During higher engine speeds, above 3200 RPM, the IMT valve opens creating a path between the 2 intake air duct runners allowing equalization of horsepower. The IMT valve is controlled by and IMT vacuum solenoid. Manifold vacuum is supplied to the fuse to the IMT solenoid. Manifold vacuum is supplied to the IMT solenoid. A 12-volt supply from the manifold fuse to the IMT solenoid is applied when the ignition key is turned ON. The solenoid is normally closed which will not allow vacuum to pass through it. When the engine speed and load are increased above a calibrated threshold the engine control module (ECM) provides a ground to the solenoid, energizing the solenoid and allowing vacuum to be applied to the IMT valve. When the IMT solenoid is commanded OFF, the voltage of the control circuit is high, battery voltage. When the IMT solenoid is commanded ON the voltage of the control circuit is low, near 2.6-4.6 volts on the control circuit to differentiate between an open, a short to ground, or a short to voltage.