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 P0660: Intake Manifold Tuning (IMT) Valve Solenoid Control Circuit
DTC P0661: Intake Manifold Tuning (IMT) Solenoid Control Circuit Low Voltage
DTC P0662: Intake Manifold Tuning (IMT) Solenoid Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Voltage | P0661* | P0660 | -- | --
IMT Control Circuit | P0661 | P0660 | P0662 | --
*Opens the fuse that supplies voltage to the IMT solenoid.

### Circuit/System Description

An intake manifold tuning (IMT) valve is used to change the intake manifold plenum configuration. When the IMT valve is open, the intake manifold is configured to one large plenum. When the IMT valve is closed, the intake manifold is configured to two smaller plenums. The IMT valve improves engine performance at low and high engine speeds.

Ignition voltage is supplied directly to the IMT solenoid. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

### Conditions for Running the DTC

• | The engine is operating.

• | The IMT solenoid has been commanded ON and OFF at least once during the ignition cycle.

• | The DTCs run continuously once 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 greater than 4 seconds, or a cumulative of 30 seconds.

### Action Taken When the DTC Sets

DTCs P0660, P0661, and P0662 are Type C DTCs.

### Conditions for Clearing the DTC

DTCs P0660, P0661, and P0662 are Type C DTCs.

### Diagnostic Aids

If the condition is intermittent, move the related harnesses and connectors with the engine operating. Monitor the scan tool Circuit Test Status parameters for the component. The Circuit Test Status parameter will change from OK or Not Run to Fault if there is a condition with the circuit or a connection.

### 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 solenoid ON and OFF with a scan tool. You should hear and feel an audible click.
2. Observe the scan tool Circuit Test Status parameter for the IMT. The parameter should display OK or Not Run.
3. 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 solenoid.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.

3. Ignition OFF, connect a test lamp between the control circuit terminal 2 and the ignition voltage circuit terminal 1.

Note: The control circuit for the IMT solenoid is pulled-up to voltage within the ECM, 2.0-3.0 volts on the control circuit is normal.

4. Ignition ON, command the IMT solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF.

⇒ | If the test lamp remains ON all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM.

⇒ | If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.

5. Test for 2.0-3.0 volts between the control circuit terminal 2 and ground.

⇒ | If the voltage is not within the specified range, replace the ECM.

6. If all circuits/connections test normal, replace the IMT solenoid.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Intake Manifold Runner Control Solenoid Replacement

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