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

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Transmission Control Module (TCM) Overtemperature

Circuit/System Description

The transmission control module (TCM) temperature sensor is located inside of the control solenoid valve assembly which has no serviceable components. The TCM monitors the TCM sensor for over temperature protection.

Conditions for Running the DTC

* Ignition voltage is 8.6 volts or greater.

* TCM temperature is between 0-170°C (32-338°F) for 0.25 second or greater.

* DTC P0634 is not set.

Conditions for Setting the DTC

Condition 1

TCM detects an internal TCM temperature condition of 146°C (295°F) or greater for 5 seconds.

Condition 2

Ignition voltage is 18 volts or greater and the TCM detects an internal temperature condition of 50°C (122°F) or greater for 2 seconds.

Action Taken When the DTC Sets

* DTC P0634 is a Type A DTC.

* TCM limits the transmission to Reverse and 5th gear operation.

* TCM inhibits Tap Up/Down function.

* TCM inhibits manual shifting of forward gears.

* TCM commands maximum line pressure.

* TCM shuts down.

Conditions for Clearing the DTC

DTC P0634 is a Type A DTC.

Reference Information

Description and Operation

Electronic Component Description Electronic Component Description for control solenoid valve assembly

DTC Type Reference

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

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, review the Failure Records when the DTC set. Verify the scan tool ECT parameter was less than 125°C (257°F).

• If greater than the specified range

Refer to Engine Overheating Engine Overheating.

• If less than the specified value

2. Verify the scan tool TCM Temperature parameter is less than 146°C (295°F)

• If greater than the specified range

Replace the Q8 control solenoid valve assembly.

• If less than the specified range

3. Test for 12.6-15.0 volts between the battery terminals with the engine running, accessories OFF.

• If not between 12.6-15.0 volts

Refer to Charging System Test Testing and Inspection.

• IF between 12.6-15.0 volts

4. Verify correct fluid level and condition. Refer to Transmission Fluid Level and Condition Check Testing and Inspection.

5. Operate the vehicle within the conditions for running and setting the DTC until normal engine temperature is reached. Verify the scan tool Trans. Fluid Temp. parameter is less than 140°C ( 284°F) and DTC P0634 did not set.

• If greater than the specified range

Inspect the transmission cooling system for obstructions to the airflow of the radiator or transmission due to debris, kinked, or damaged transmission fluid lines, or damage to the transmission cooler.

• If problems with cooling system are found, repair or replace as necessary.

• If no problems are found with cooling system, refer to Refer to Transmission Fluid Cooler Flushing and Flow Test Transmission Fluid Cooler Flushing and Flow Test.

• If less than the specified value and DTC P0634 set

Replace the Q8 control solenoid assembly.

• If less than the specified value and DTC P0634 did not set

6. After performing the above steps, verify that the DTC does not reset by operating 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. If the vehicle passes the Circuit/System Verification procedure, refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections.

Repair Instructions

Note:

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

* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection.

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References for control solenoid valve assembly replacement, setup, and programming