Transmission Fluid Temperature Gauge Inaccurate or Inoperative

Transmission Fluid Temperature Gauge Inaccurate or Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Circuit/System Description

The auxiliary gauge module displays the transmission fluid temperature based on the information either from the engine control module (ECM) or the transmission control module (TCM). The ECM or the TCM converts the data from the transmission oil temperature sensor to a transmission fluid temperature signal. The ECM or the TCM sends the transmission oil temperature signal via a High Speed CAN-Bus signal to the body control module (BCM). The BCM then sends the information via a Low Speed CAN-Bus signal to the auxiliary gauge module to display the transmission fluid temperature.

Reference Information
Schematic Reference

Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Auxiliary Gauges Description and Operation (Auxiliary Gauges Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

without TCM
1. Ignition ON, perform the Auxiliary Gauge Sweep test with the scan tool, verify that the transmission fluid temperature gauge sweeps from its low to high position.

• If the transmission fluid temperature gauge does not sweep, replace the P26 Auxiliary Gauge Module.

2. If the engine oil pressure gauge does sweep, replace the K20 Engine Control Module.

with TCM
1. Ignition ON, perform the Auxiliary Gauge Sweep test with the scan tool, verify that the transmission fluid temperature gauge sweeps from its low to high position.

• If the transmission fluid temperature gauge does not sweep, replace the P26 Auxiliary Gauge Module.

2. If the engine oil pressure gauge does sweep, replace the K71 Transmission Control Module.

Repair Instructions

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

Control Module References (Programming and Relearning) for Auxiliary Gauge Module, TCM or ECM replacement, setup, and programming