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 P061B: Control Module Torque Calculation Performance
DTC P161B: Control Module Torque Performance

### Circuit/System Description

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM) and the throttle actuator control (TAC) system.

### Conditions for Running the DTC

The ignition is ON, or the engine is running.

### Conditions for Setting the DTC

#### P061B

The ECM detects an internal control module torque calculation performance condition.

#### P161B

The ECM detects that the delivered torque does not match the desired torque.

### Action Taken When the DTC Sets

DTCs P061B, and P161B are Type A DTCs.

### Conditions for Clearing the DTC

DTCs P061B, and P161B are Type A DTCs.

### Reference Information

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. DTCs P061B or P161B should not set.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data to verify the DTC does not reset.

### Circuit/System Testing

Important: In extreme cold weather conditions ice may form in the vacuum hose to the MAP sensor and may set a DTC. Inspect the MAP sensor vacuum hose for ice, or other restrictions.

1. Ignition ON, observe the scan tool MAP sensor parameter. Start the engine, verify the MAP sensor data parameter changes.

⇒ | If the MAP parameter does not change, refer to DTC P0107 or P0108 for further diagnosis.

2. Verify there is not an engine vacuum leak.
3. Test for a parasitic load on the following components:

• | Generator

• | A/C compressor

• | Transmission

⇒ | If a condition is found, repair as necessary.

4. If all conditions test normal, replace the ECM

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming