P1684

DTC P1684, P1685 or P1686

Diagnostic Instructions

^ Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
^ Review Strategy Based Diagnosis for an overview of the diagnostic approach.
^ Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

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

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 500 RPM or greater for 5 seconds.
^ The ignition voltage is between 8.6 colts and 19.0 volts.

DTC P1684

^ No TFT DTCs P0711, P0712, or P0713.
^ No ISS DTCs P0716 or P0717.
^ No OSS DTCs P0722 or P0723.
^ DTC P1684 has not passed this key ON.
^ The TCM power up temperature is between -39 and +149°C (-38 and +300°F) for Fail Case 1 and 2.

DTC P1685

^ No ISS DTCs P0716 or P0717.
^ No OSS DTCs P0722 or P0723.
^ The transmission output shaft speed is 200 RPM or greater for 200 seconds or more.
^ The torque converter clutch (TCC) slip speed is 120 RPM or greater for 200 seconds or more.
^ DTC P1686 has not failed this ignition cycle.

DTC P1686

DTC P1686 has not failed this ignition cycle.

Conditions for Setting the DTC

DTC P1684

Fail Case 1

^ Vehicle speed is 8 km/h (5 mph) or greater for 300 seconds cumulative.
^ TCC slip speed is greater than 120 RPM for 300 seconds cumulative.
^ the TCM power up temperature is between -40 and +21°C (-40 and +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 70°C (158°F) or greater.
^ The TFT has increased by 55°C (99°F) since start-up.

Fail Case 2

^ Vehicle speed is 8 km/h (5 mph) or greater 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 TFT is 70°C (158°F) or greater.
^ The TFT has increased by 55°C (99°F) since start-up.

Fail Case 3

The TCM power up temperature changes by 20°C (36°F) or greater 14 times over 7 seconds.
DTC P1685

The TCM power up temperature is -59°C (-74°F) or less for 10 seconds or greater.
DTC P1686

The TCM power up temperature is 164°C (327°F) or more for 10 seconds or greater.

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

Automatic Transmission Controls Schematics

Connector End View Reference

^ Automatic Transmission Inline 20-Way Connector End View
^ Automatic Transmission Internal Connector End Views
^ Automatic Transmission Related 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 Testing

1. Clear the DTC and operate the vehicle under the Conditions for Running the DTC and the Conditions for Setting the DTC.
2. Shut the ignition OFF for 30 seconds, and then verify that the DTC does not reset.
- 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. Control Solenoid Valve and Transmission Control Module Assembly Inspection

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

1. Control solenoid (w/body and TCM) valve assembly replacement. Refer to Control Module References for replacement, setup, and programming. Programming and Relearning
2. Perform the Service Fast Learn Adapts. Programming and Relearning