Transmission Fluid Temperature Gauge Malfunction
Transmission Fluid Temperature Gauge Malfunction
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 serial data to the body control module (BCM). The BCM then sends the information via serial data 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 Fuel Pump and Level Sensor Assembly - Primary
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 Control Module References for scan tool information
Circuit/System Verification
Manual Transmission
1. Ignition ON, perform the Auxiliary Gauge Sweep test with the scan tool, verify all auxiliary gauges sweep from the low to high positions.
• If none of the auxiliary gauges sweep properly
Refer to Auxiliary Gauges Malfunction Auxiliary Gauges Malfunction.
• If one, two, or three of the auxiliary gauges sweep properly
Replace the P26 Auxiliary Gauge Module.
• If all auxiliary gauges sweep properly
2. Verify the Transmission Temperature Gauge display matches the Auxiliary Gage Module scan tool Transmission Fluid Temperature parameter.
• If the transmission fluid temperature gauge does not match the scan tool parameter
Replace the P26 Auxiliary Gauge Module.
• If the transmission fluid temperature gauge matches the scan tool parameter
3. Verify the scan tool Transmission Fluid Temperature parameter is between -74 and +174°C (-101 and +345°F) and changes with transmission temperature changes.
• If parameter is not between -74 and +174°C (-101 and +345°F) or changes with transmission temperature changes
Refer to Circuit/System Testing- Manual Transmission.
• If parameter is between -74 and +174°C (-101 and +345°F) and changes with transmission temperature changes
4. All OK.
Automatic Transmission
1. Ignition ON, perform the Auxiliary Gauge Sweep test with the scan tool, verify all auxiliary gauges sweep from the low to high positions.
• If none of the auxiliary gauges sweep properly
Refer to Auxiliary Gauges Malfunction Auxiliary Gauges Malfunction.
• If one, two, or three of the auxiliary gauges sweep properly
Replace the P26 Auxiliary Gauge Module.
• If all auxiliary gauges sweep properly
2. Verify the Transmission Temperature Gauge display matches the Transmission Control Module scan tool Transmission Fluid Temperature parameter.
• If the transmission fluid temperature gauge does not match the scan tool parameter
Replace the P26 Auxiliary Gauge Module.
• If the transmission fluid temperature gauge matches the scan tool parameter
3. Verify the scan tool Transmission Fluid Temperature parameter is between -74 and +174°C (-101 and +345°F) and changes with transmission temperature changes.
• If parameter is not between -74 and +174°C (-101 and +345°F) or changes with transmission temperature changes
Refer to DTC P0711-P0713 P0711.
• If parameter is between -74 and +174°C (-101 and +345°F) and changes with transmission temperature changes
4. All OK.
Circuit/System Testing
Manual Transmission
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B173 Manual Transmission Fluid Temperature Sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 1 V between the low reference circuit terminal A and ground.
• If 1 V or greater
repair the short to voltage on the circuit.
• If less than 1 V
3. Test for less than 10 ohms between the low reference circuit terminal A and ground.
• If 10 ohms or greater
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If less than 10 ohms
4. Ignition ON.
5. Verify the scan tool Transmission Fluid Temperature parameter is greater than 155 degrees C.
• If 155 degrees C or less
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K20 Engine Control Module.
• If greater than 155 degrees C
6. Install a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal A.
7. Verify the scan tool Transmission Fluid Temperature parameter is less than 5 degrees C.
• If 5 degrees C or greater
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V
3. Ignition OFF
4. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If less than 5 degrees C
8. Test or replace the B173 Manual Transmission Fluid Temperature Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
Control Module References Control Module References for Auxiliary Gauge Module, TCM or ECM replacement, programming, and setup