• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
A thermistor is imbedded in the transmission control module (TCM). There are no external circuits. The TCM monitors the temperature and will take action to prevent damage to the TCM.
• | Engine speed is greater than 200 RPM for 5 seconds. |
• | Ignition and battery voltage is between 9-18 V. |
This DTC sets when the TCM internal temperature is greater than 140°C (284°F) for 10 seconds.
• | The TCM does not request the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
• | DTC P0634 is stored in TCM history. |
• | The TCM shuts down and all power is removed from the solenoids. |
• | The transmission goes to a hydraulic default mode and will operate in reverse, neutral, and first, third, or fifth range. |
DTC P0634 is a Type C DTC.
• | Inspect the mounting of the TCM and damage or missing heat shields. |
• | You may have to drive the vehicle in order to experience a condition. |
Automatic Transmission Controls Schematics
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Note: You must perform the Circuit/System Verification first.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for TCM replacement, setup, and programming |
If another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.