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

#### P061B or P161B

The ignition is ON, or the engine is operating.

### 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

#### Description and Operation

Engine Control Module Description

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Verification

1. Ignition ON, observe the scan tool DTC information parameter. DTCs P061B or P0161B should not set.
2. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

### Circuit/System Testing

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

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

⇒ | If the MAP data 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 engine control module replacement, setup, and programming