2010 Cadillac Truck SRX FWD V6-3.0L Page 1631
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
* The ignition voltage is greater than 8.6 volts.
* The TCM temperature is between 0-170掳C (32-338掳F) for 0.25 second or greater.
* DTC P0634 has not set this ignition cycle.
Conditions for Setting the DTC
Condition 1
The TCM detects an internal temperature condition greater than 146掳C (295掳F) for 5 seconds or greater.
Condition 2
The ignition voltage is greater than 18 volts and the TCM detects an internal temperature condition greater than 50掳C (122掳F) for 2 seconds.
Action Taken When the DTC Sets
* DTC P0634 is a Type A DTC.
* The TCM defaults the transmission to reverse and 3rd or 5th gear operation.
* The TCM inhibits Tap Up/Down function.
* The TCM inhibits manual shifting of forward gears.
* The TCM commands maximum line pressure.
* The TCM shuts down.
Conditions for Clearing the DTC
DTC P0634 is a Type A DTC.
Reference Information
Description and Operation
Electronic Component Description (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Description and Operation/6T70/6T75 -
Automatic Transmission/Electronic Component Description) for control solenoid valve assembly
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, review the Failure Records when the DTC set. Verify the scan tool ECT Sensor parameter is less than 125掳C (257掳F).
瀚慖f greater than the specified range, refer to Engine Overheating (See: Engine, Cooling and Exhaust/Cooling System/Testing and
Inspection/Symptom Related Diagnostic Procedures/Engine Overheating).
2. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals with a DMM. The voltage should be
between 12.6-15.0 volts.
瀚慖f not within the specified range, or the charge indicator light is ON, refer to Charging System Test (See: Starting and Charging/Testing
and Inspection/Component Tests and General Diagnostics/Charging System Test).
3. Perform the Transmission Fluid Level and Condition Check (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing
and Inspection/Component Tests and General Diagnostics/6T70/6T75 - Automatic Transmission/Transmission Fluid Level and Condition
Check) to verify correct fluid level and condition.
4. Perform the Transmission Fluid Cooler Flushing and Flow Test (See: Transmission and Drivetrain/Automatic
Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/6T70/6T75 - Automatic
Transmission/Transmission Fluid Cooler Flushing and Flow Test) to verify proper transmission oil cooler flow.
5. Operate the vehicle within the conditions for running and setting the DTC until normal engine temperature is reached. Verify the scan tool
TCM Temperature parameter is less than 146掳C (295掳F).
瀚慖f 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 all the items test normal, replace the
