P0634

DTC P0634

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0634
- Control Module Overtemperature

Circuit/System Description

The transmission control module temperature sensor is located inside of the control solenoid valve assembly which has no serviceable parts. The Transmission Control Module monitors the Transmission Control Module sensor for over temperature protection.

Conditions for Running the DTC

* Ignition voltage is between 8.6-32 V.

* The TCM temperature is between 0°C (32°F) and 170°C (338°F) for 0.25 seconds.

* DTC P0634 is not set.

Conditions for Setting the DTC

Condition 1

The TCM has detected an internal temperature condition greater than 142°C (288°F) for 5 seconds.

Condition 2

Ignition voltage is equal to or greater than 18 volts and the TCM temperature is greater than 50°C (122°F) for 2 seconds.

Action Taken When the DTC Sets

* DTC P0634 is a Type A DTC.

* The TCM shifts to a default gear, shuts down, and turns OFF.

* The TCM disables TAP shift operation.

* The TCM enables torque management.

Conditions for Clearing the DTC

DTC P0634 is a Type A DTC.

Diagnostic Aids

During a road test, the TCM temperature should steadily increase to a normal operating temperature, then stabilize.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics Electrical Diagrams

Connector End View Reference

* Component Connector End Views 5 Bow Lowered Switch (CM7)

* Inline Harness Connector End Views X102

Description and Operation

Electronic Component Description Electronic Component Description

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Special Tools

DT-47825-10 - Jumper Harness

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Circuit/System Verification

1. Verify the transmission fluid level and condition is correct. Refer to Transmission Fluid Level and Condition Check Transmission Fluid Level and Condition Check.

2. Operate the vehicle until normal engine temperature is reached.

3. Verify with a scan tool the ECT Sensor parameter is less than 125°C (257°F).

• If greater than 125°C (257°F)
Refer to Symptoms - Engine Cooling Symptoms - Engine Cooling.

• If less than 125°C (257°F)

4. Verify the scan tool Transmission Control Module Temperature is less than 142°C (287°F).

• If greater than 142°C (287°F)
Inspect the transmission fluid lines for being misrouted, kinked, or damage. Repair or replace as necessary. If the transmission fluid lines are OK, replace the Q8 Control Solenoid Valve Assembly.

• If less than 142°C (287°F)

5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observe from the Freeze Frame/Failure Records data.

6. Verify the DTC does not set.

• If the DTC sets
Replace the Q8 Control Solenoid Valve Assembly.

• If the DTC does not set

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Perform the Reset Transmission Adapts Reset Procedure following all transmission related repairs.

* Refer to Transmission Fluid Cooler Hose/Pipe Replacement Transmission Fluid Cooler Hose/Pipe Replacement

* Refer to Transmission Fluid Cooler Upper Pipe Replacement - Rear Transmission Fluid Cooler Upper Pipe Replacement - Rear

* Refer to Transmission Fluid Cooler Upper Pipe Replacement - Rear to Differential Cooler Transmission Fluid Cooler Upper Pipe Replacement - Rear to Differential Cooler

* Refer to Transmission Fluid Cooler Lower Pipe Replacement - Intermediate Transmission Fluid Cooler Lower Pipe Replacement - Intermediate

* Refer to Transmission Fluid Cooler Lower Pipe Replacement - Intermediate to Differential Cooler Transmission Fluid Cooler Lower Pipe Replacement - Intermediate to Differential Cooler

* Refer to Control Module References Control Module References for Control Solenoid Valve Assembly replacement, programming, and setup.