DTC P0634
Diagnostic Instructions
DTC Descriptor
DTC P0634: Control Module Over-Temperature
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
• |
The TCM temperature is between 0°C (32°F)
and 240°C (464°F) for 0.25 second or greater. |
• |
The ignition voltage is greater than
9.0 volts. |
Conditions for Setting the DTC
Condition 1
The TCM has detected an internal temperature condition greater
than 144°C (291°F) for 5 seconds or greater.
Condition 2
The ignition voltage is 18 volts or greater 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 limits the transmission to 5th gear and
reverse. |
• |
The TCM inhibits Tap Up/Down function. |
• |
The TCM enables torque management. |
• |
The TCM commands maximum line pressure. |
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 stabilise.
Reference Information
Description and Operation
Electronic Component Description for control solenoid valve
assembly information.
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Note: If DTC P0218 is set,
diagnose that DTC first.
- Ignition ON, review the Failure Records when the DTC
set. Verify the scan tool Engine Coolant Temperature parameter was
less than 125°C (257°F).
- Perform the
Transmission Fluid Level and Condition Check to verify correct
fluid level and condition.
- Perform the
Transmission Fluid Cooler Flushing and Flow Test to verify
proper transmission oil cooler flow.
- 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°C (295°F).
⇒ |
If greater than the specified range, inspect the
transmission cooling system. 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 Q8 control solenoid valve
assembly. |
- 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 then, refer to
Testing for Intermittent Conditions and Poor Connections .
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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