DTC P0662: Intake Manifold Tuning Valve Control Circuit High: Description

The intake air duct is divided into two 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 two separate runner paths in the incoming air ducts which aids an increasing torque. During higher engine speeds, above 3,200 RPM, the IMT valve opens creating a path between the two intake air duct runners allowing equalization of the intake air pressure which aids in increasing horsepower. The IMT valve is controlled by an IMT vacuum 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 0 volts. The ECM applies a pull up voltage of 2.6-4.6 volts on the control circuit to differentiate between an open, a short to ground, or a short to voltage. If the ECM detects a voltage above a predetermined threshold, DTC P0662 will set.