P1685

DTC P1684, P1685 or P1686

DTC Descriptor
This diagnostic procedure supports the following DTCs:
^ DTC P1684 Transmission Control Module (TCM) Power Up Temperature Sensor Performance
^ DTC P1685 Transmission Control Module (TCM) Power Up Temperature Sensor Circuit Low Voltage
^ DTC P1686 Transmission Control Module (TCM) Power Up Temperature Sensor Circuit High Voltage

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description
The transmission control module (TCM) power up temperature sensor is located inside of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The TCM power up temperature sensor provides the temperature of the TCM at TCM power up. This temperature reading is used in various shifting and 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 greater than 450 RPM.

DTC P1684
^ No DTCs P0711, P0712, P0713, P0716, P0717, P0722, P0723, or P1684.
^ DTC P1684 has not passed this key ON.
^ The TCM power up temperature is between -39 - 149°C (-38 - 300°F).

DTC P1685
^ No DTCs P0716, P0717, P0722, or P0723.
^ 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 P1685 has not failed this ignition cycle.

DTC P1685
DTC P1686 has not failed this ignition cycle.

Conditions for Setting the DTC

DTC P1684

Fail Case 1
^ 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 power up temperature is between -40 - 21°C (-40 - 70°F).
^ The TCM power up temperature has changed by less than 2°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 start-up.

Fail Case 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 temperature sensor is between 120 - 150°C (248 - 302°F).
^ The TCM power up temperature has changed by less than 2°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 start-up.

Fail Case 3
The TCM power up temperature changes by greater than or equal to 20°C (36°F) 14 times over 7 seconds.

DTC P1685
The TCM power up temperature is less than or equal to -61°C (-77°F) for greater than 10 seconds.

DTC P1686
The TCM power up temperature is greater than or equal to 161°C (321°F) for greater than 10 seconds.

Action Taken When the DTC Sets
^ DTCs P1684, P1685, and P1686 are Type C DTCs.
^ The TCM allows the vehicle to operate in transmission protection mode.

Conditions for Clearing the DTC
DTCs P1684, P1685, and P1686 are Type C DTCs.

Diagnostic Aids
Reprogram the TCM and retest the DTC to see if the DTC resets.

Reference Information

Schematic Reference

Connector End View Reference
^ Automatic Transmission Inline 16-Way Connector End View
^ Automatic Transmission Internal Connector End Views

DTC Type Reference
^ Diagnostic Trouble Code (DTC) Type Definitions
^ Diagnostic Trouble Code (DTC) List/Type

Electrical Information Reference
^ Circuit Testing
^ Connector Repairs
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs

Circuit/System Verification
1. Start the Engine for 1 minute and observe 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.

Circuit/System Testing
1. Clear the DTC and operate the vehicle under the condition for running and setting the DTC.
2. Shut the ignition OFF for 30 seconds, and 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 (w/body and TCM) valve assembly inspection procedure.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Control solenoid (w/body and TCM) valve assembly replacement.