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 (TCM) temperature sensor is located inside of the control solenoid valve assembly which has no serviceable components. The TCM monitors the TCM temperature sensor for over temperature protection.
Conditions for Running the DTC
* Ignition voltage is greater than 8 V.
* TCM temperature is between 0-170°C (32-338°F) for 0.25 s.
Conditions for Setting the DTC
Condition 1
TCM detects an internal temperature condition of 146°C (295°F) or greater for 5 s.
Condition 2
Ignition voltage is 18 V or greater and the TCM detects an internal temperature of 50°C (122°F) or greater for 2 s.
Action Taken When the DTC Sets
* DTC P0634 is a Type A DTC.
* TCM limits the transmission to Reverse and 4th or 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.
Diagnostic Aids
During a road test, the TCM temperature should steadily increase to a normal operating temperature, and then stabilize.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
* Component Connector End Views Fuel Pump and Level Sensor Assembly
* Inline Harness Connector End Views X105
Description and Operation
* Transmission General Description Transmission General Description
* Transmission Component and System Description Transmission Component and System Description
* 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
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool Engine Coolant Temperature parameter was less than 125° C (257° F) when DTC set by reviewing the scan tool Freeze Frame/Failure Records.
• If 125° C (257° F) or greater
Refer to Engine Overheating Engine Overheating.
• If less than 125° C (257° F)
3. Verify the transmission fluid level and condition is correct. Refer to Transmission Fluid Level and Condition Check Transmission Fluid Level and Condition Check.
• If the transmission fluid level and condition is not correct
Repair as necessary.
• If the transmission fluid level and condition is correct
4. Clear the TCM DTCs with a scan tool.
5. Operate the vehicle until normal engine temperature is reached.
6. Verify the scan tool Transmission Fluid Temperature parameter is less than 140° C (284° F).
• If 140° C (284° F) or greater
1. Ignition OFF.
2. Verify the conditions listed below do not exist:
* Obstructions to the airflow to the radiator or transmission
* Radiator damage
* Transmission cooler damage
* Transmission cooler pipe kinked or damaged
• If a condition exists, repair or replace as necessary.
• If no condition exists, refer to Transmission Fluid Cooler Flushing and Flow Test Transmission Fluid Cooler Flushing and Flow Test.
• If less than 140° C (284° F)
7. Verify DTC P0634 does not set.
• If the DTC sets
Replace the Q8 Control Solenoid Valve Assembly.
• If the DTC does not set
8. Operate 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 Record data.
9. Verify the DTC does not set.
• If the DTC sets
Replace the Q8 Control Solenoid Valve Assembly.
• If the DTC does not set
10. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repairs.
* Perform the Reset Transmission Adapts Reset Procedure following all transmission repairs.
* Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection Transmission Fluid Cooler Hose/Pipe Quick-Connect Fitting Disconnection and Connection
* Transmission Fluid Auxiliary Cooler Inlet Pipe Replacement Transmission Fluid Auxiliary Cooler Inlet Pipe Replacement
* Transmission Fluid Auxiliary Cooler Outlet Pipe Replacement Transmission Fluid Auxiliary Cooler Outlet Pipe Replacement
* Transmission Fluid Cooler Pipe Connector Replacement - Radiator Transmission Fluid Cooler Pipe Connector Replacement - Radiator
* Control Module References Control Module References for Control Solenoid Valve Assembly replacement, programming, and setup