GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Silverado - 4WD 🢒 DTC 🢒 DTC P0667, P0668, or P0669

Diagnostic Instructions
    • 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.

DTC Descriptors

DTC P0667:  Transmission Control Module (TCM) Temperature Sensor Performance

DTC P0668:  Transmission Control Module (TCM) Temperature Sensor Circuit Low Voltage

DTC P0669:  Transmission Control Module (TCM) Temperature Sensor Circuit High Voltage

Circuit/System Description

The transmission control module (TCM) temperature sensor is located inside of the control solenoid (w/body and TCM) valve assembly and has no serviceable parts. The TCM temperature sensor provides the temperature of the TCM. This temperature reading is used in various diagnostic routines in the TCM software. This fault is handled inside the TCM and no external circuits are involved.

Conditions for Running the DTC
    • The engine speed is 500-7500 RPM for at least 5 seconds.
    • Ignition voltage is between 8.6-18.0 volts.
    • TCM internal temperature is -54°C to +149°C (-38°F to +300°F).
    • No DTCs P0716, P0717, P0722, or P0723.

DTC P0667

    • No DTCs P0667, P0711, P0712, or P0713.
    • DTC P0667 has not passed this key ON.
    • The TCM internal temperature is between -39°C and +149°C (-38°F and +300°F).

DTC P0668

DTC P0668 has not failed this ignition cycle.

DTC P0669

    • The transmission output shaft speed is greater than 200 RPM for greater than 200 seconds.
    • The TCC slip speed is equal to or greater than 120 RPM for 200 seconds or greater.
    • DTC P0669 has not failed this ignition cycle.

Conditions for Setting the DTC

P0667 - Condition 1

    • Vehicle speed is greater than 8 km/h (5 mph) for 300 seconds cumulative.
    • Torque converter clutch (TCC) slip speed is greater than 120 RPM for 300 seconds cumulative.
    • The TCM internal temperature is between -55°C and +21°C (-67°F and +70°F).
    • The TCM internal temperature has changed by less than 2.0°C (3.6°F) in 100 seconds.
    • The transmission fluid temperature (TFT) is greater than 70°C (158°F).
    • The TFT has increased by 55°C (99°F) since startup.

P0667 - Condition 2

    • Vehicle speed is greater than 8 km/h (5 mph) for 300 seconds cumulative.
    • TCC slip speed is greater than 120 RPM for 300 seconds cumulative.
    • The TCM internal temperature is between 120-150°C (248-302°F).
    • The TCM internal temperature has changed by less than 2.0°C (3.6°F) in 100 seconds.
    • The TFT is greater than 70°C (158°F).
    • The TFT has increased by 55°C (99°F) since startup.

P0667 - Condition 3

The TCM internal temperature changes by greater than or equal to 20°C (36°F) 14 times over 7 seconds.

P0668

The TCM internal temperature is greater than 249°C (480°F) for greater than 4 seconds.

P0669

The TCM internal temperature is less than -249°C (-416°F) for greater than 10 seconds.

Action Taken When the DTC Sets
    • DTCs P0667, P0668, and P0669 are Type C DTCs.
    • The TCM allows the vehicle to operate in transmission protection mode.

Conditions for Clearing the DTC

DTCs P0667, P0668, and P0669 are Type C DTCs.

Diagnostic Aids

Reprogram the TCM and retest the DTC to see if the DTC resets. Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection before replacing the control solenoid (w/body and TCM) valve assembly.

Reference Information

Description and Operation

Electronic Component Description

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Verification

DTC P0667

  1. Start the engine and operate the vehicle at 64 km/h (40 mph) while observing the TCM power up temperature sensor and the TCM temperature sensor.
  2. The system is operating normally if the TCM power up temperature is within 10°C (18°F) of the TCM temperature sensor.

DTCs P0668 and P0669

Start the engine and check for DTCs P0668 and P0669.

Circuit/System Testing
  1. Clear the DTC and operate the vehicle under the condition for running and setting the DTC.
  2. Verify that the DTC does not reset.
    3. ⇒If the DTC resets, replace the control solenoid (w/body and TCM) valve assembly.

Component Testing

Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    • Control solenoid (w/body and TCM) valve assembly replacement. Refer to Control Module References for replacement, setup, and programming.
    • Perform the Service Fast Learn Adapts if internal transmission repairs are performed.