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 Descriptor

DTC P0661 00: Intake Manifold Tuning Valve Solenoid Control Circuit Low Voltage
DTC P0662 00: Intake Manifold Tuning Valve Solenoid Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Ignition 1 Voltage Circuit | P0661 00 | -- | P0661 00 | -- | --
Intake Manifold Tuning Valve Solenoid Control Circuit | P0661 00 | -- | P0661 00 | P0662 00 | --

### Circuit/System Description

The intake manifold tuning solenoid valve system uses variable air induction tuning in order to achieve maximum performance and efficiency over the entire operating range of the engine. The characteristic torque curve of a normally aspirated engine depends mainly on how the engine's average pressure changes over the engine speed range. The average pressure is proportional to the volume of the air mass present in the cylinder when the inlet valve is closed. The design of the inlet system determines how large an air mass can be drawn into a cylinder at a given engine speed. An intake manifold tuning solenoid valve is used to change the intake manifold plenum configuration. When the intake manifold tuning solenoid valve is open, the intake manifold is configured to one large plenum. When the intake manifold tuning solenoid valve is closed, the intake manifold is configured to 2 smaller plenums. The 2 intake manifold plenum sizes result in different torque curves, which improves performance at low and high engine speeds. During low speed, high load conditions, the intake manifold tuning solenoid valve is closed creating a longer runner path inside the plenum, which increases torque. During higher engine speeds and loads, the intake manifold tuning solenoid valve opens, creating a shorter runner path inside the plenum, which increases horsepower.

The intake manifold tuning solenoid valve actuator solenoid has the following circuits:

• | Ignition voltage

• | Intake manifold tuning solenoid valve actuator solenoid control

### Conditions for Running the DTC

• | DTC P0606 00 is not set.

• | The ignition is ON, or the engine is running.

• | The battery voltage is greater than 9 V.

• | DTCs P0661 00 and P0662 00 run continuously when the above conditions are met.

### Conditions for Setting the DTC

#### P0661 00

The ECM detects a short to ground or an open on the intake manifold tuning solenoid valve actuator solenoid control circuit for greater than 2 s.

#### P0662 00

The ECM detects a short to voltage on the intake manifold tuning solenoid valve actuator solenoid control circuit for greater than 2 s.

### Action Taken When the DTC Sets

DTCs P0661 00 and P0662 00 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0661 00 and P0662 00 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### 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. Use the scan tool output controls to command the Q22 Intake Manifold Tuning (IMT) Solenoid Valve parameter open and closed. Verify that the diaphragm arm moves at least once when there is sufficient vacuum in the storage tank.
2. Use the scan tool output controls to command the Q22 Intake Manifold Tuning (IMT) Solenoid Valve parameter open and closed. An audible click should be heard and felt.
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 Q22 Intake Manifold Tuning (IMT) Solenoid Valve.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate test the ignition circuit for a short to ground or an open/high resistance.

3. Connect a test lamp between the control circuit terminal 2 and the ignition circuit terminal 1.
4. Command the Q22 Intake Manifold Tuning (IMT) Solenoid Valve Open and Closed with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

⇒ | If the test lamp is always OFF, test the control circuit terminal 2 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

5. If the circuits test normal, test or replace the Q22 Intake Manifold Tuning (IMT) Solenoid Valve.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | LINK (Intake Manifold Tuning Actuator Solenoid Replacement)

• | Control Module References for replacement, setup, and programming.