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 P150C: Transmission Control Module (TCM) Engine Speed Request Circuit

### Circuit/System Description

The transmission control module (TCM) and the engine control module (ECM) monitor the number of Engine Speed Request Circuit serial data messages transmitted/received between modules. If the ECM detects a faulty message count, DTC P150C sets.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

The ECM detects greater than 2 message count errors.

### Action Taken When the DTC Sets

• | The ECM Disables engine speed requests from transmission.

• | DTC P150C is a type B DTC.

### Conditions for Clearing the DTC

DTC P150C is a type B DTC.

### Diagnostic Aids

A problem on the serial data circuit will not cause this DTC.

### Reference Information

#### Description and Operation

Data Link Communications Description and Operation

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

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.

⇒ | If the DTC resets, replace the control solenoid (w/body and TCM) valve assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.