For 1990-2009 cars

### 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 Descriptors

DTC P0661: Intake Manifold Tuning (IMT) Valve Solenoid Control Circuit Low Voltage
DTC P0662: Intake Manifold Tuning (IMT) Valve Solenoid Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage | * | P0661 | -- | --
IMT Valve Control Circuit | P0661 | P0661 | P0662 | --
* The Engine Cranks but Does Not Run and opens the fuse that supplies voltage to the IMT valve solenoid.

### Circuit/System Description

An ignition 1 voltage is supplied directly to the intake manifold tuning (IMT) valve solenoid. The engine control module (ECM) controls the IMT valve solenoid by grounding the control circuit via an internal driver switch. The primary function of the driver is to supply ground for the IMT valve solenoid. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the voltage on the control circuit.

### Conditions for Running the DTC

• | The ignition is ON.

• | DTCs P0661 and P0662 run continuously when the above condition is met.

### Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for more than 2 seconds.

### Action Taken When the DTC Sets

DTCs P0661 and P0662 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0661 and P0662 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Air Intake System Description

#### 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 for scan tool information

### Circuit/System Verification

1. Ignition On, command the IMT valve solenoid ON and OFF with a scan tool. You should hear and feel an audible click.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the IMT valve solenoid.
2. Ignition ON, test for battery voltage between the ignition 1 voltage circuit terminal 2 and ground.

⇒ | If less than B+, repair the ignition 1 voltage circuit for a short to ground or an open/high resistance. Replace the fuse, if necessary.

3. Ignition OFF, connect a test lamp between the control circuit terminal 1 and the ignition 1 voltage circuit terminal 2.
4. Ignition ON, command the IMT valve solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF with the command.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the IMT valve solenoid.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Intake Manifold Tuning Valve Actuator Solenoid Replacement

• | Control Module References for engine control module replacement, setup, and programming