DTC P0634
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0634
- 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 parts.
The TCM monitors the TCM sensor for over temperature protection.
Conditions for Running the DTC
* Ignition voltage is between 8.6 volts or greater.
* The TCM temperature is between 0锟斤拷C (32锟斤拷F) and 170锟斤拷C (338锟斤拷F) for 0.25 seconds.
* DTC P0634 and has not set this ignition.
Conditions for Setting the DTC
Condition 1
The TCM has detected an internal temperature condition greater than 142锟斤拷C (288锟斤拷F) for 5 seconds.
Condition 2
Ignition voltage is equal to or greater than 18 volts and the TCM temperature is greater than 50锟斤拷C (122锟斤拷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
Description and Operation
Electronic Component Description (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and
Operation/6L45/6L50/6L80/6L90 - Automatic Transmission/Electronic Component Description)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Circuit/System Verification
Note: If DTC P0218 is set, diagnose that DTC first.
1. Perform the Transmission Fluid Level and Condition Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing
and Inspection/Initial Inspection and Diagnostic Overview/6L45/6L50/6L80/6L90 - Automatic Transmission/Transmission Fluid Level and
Condition Check) to verify correct fluid level and condition.
