Diagnostic Test

Before performing this Diagnostic Test, be certain that there are no problems that could cause the Transmission to overheat. Check for restricted transmission oil cooler and lines, air flow restrictions, and low transmission fluid. Towing loads weighing more than the recommended towing capacity could cause excessively high transmission temperatures.

CHECK FOR ENGINE COOLING DTCS
1. With the scan tool, read Engine DTCs.
  Are any engine cooling or Active Grille Shutter (AGS) DTCs present?
  
  Yes
  - Refer to the DTC INDEX article and perform the appropriate diagnostic procedure.
  No
  - Go To 2
CHECK FOR OTHER TRANSMISSION DTCS
1. With the scan tool, read Transmission DTCs.
2. Record any Transmission Freeze Frame data.
  Are there any other transmission DTCs?
  
  Yes
  - Perform the appropriate diagnostic procedure in the Service Information.
  No
  - Go To 3
CHECK IF DTC IS CURRENT
1. Using the scan tool, read TCM DTCs.
2. Record the Environmental Data and any DTCs.
3. Clear DTCs.
4. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
5. Read TCM DTCs.
  Did the DTC reset?
  
  Yes
  - Go To 4
  No
  - Go To 9
CHECK TRANSMISSION TEMPERATURE SENSOR CIRCUITS FOR HIGH RESISTANCE
1. Turn the Ignition OFF.
2. Disconnect the TCM harness connector.
3. Remove the transmission side cover and disconnect the transmission temperature sensor harness connector.
4. Connect a jumper between the (T54) Transmission Temperature Signal circuit and the (T820) Sensor Ground circuit at the transmission temperature sensor harness connector.
5. Measure resistance between (T54) Transmission Temperature Signal circuit and the (T820) Sensor Ground circuit at the TCM harness connector.
  Is the resistance below 5.0 ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (T54) Transmission Temperature Signal circuit or the (T820) Sensor Ground circuit for an open or high resistance.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK TRANSMISSION TEMPERATURE SENSOR CIRCUITS FOR A SHORT TO GROUND
1. With the jumper still connected, measure resistance between (T54) Transmission Temperature Signal circuit at the TCM harness connector and ground.
  Is there continuity between (T54) Transmission Temperature Signal circuit and ground?
  
  Yes
  - Repair the (T54) Transmission Temperature Signal circuit or (T820) Sensor Ground circuit for a short to ground.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 6
CHECK THE (T54) TRANSMISSION TEMPERATURE SIGNAL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
1. Remove the jumper from the transmission temperature sensor harness connector.
2. Measure resistance between (T54) Transmission Temperature Signal circuit and all other circuits in the TCM harness connector.
  Is there continuity between (T54) transmission temperature signal circuit and any other TCM circuit?
  
  Yes
  - Repair the (T54) Transmission Temperature Signal circuit for a short to another circuit.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 7
CHECK THE (T820) SENSOR GROUND CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
1. Measure resistance between (T820) Sensor Ground circuit and all other circuits in the TCM harness connector.
  Is there continuity between (T820) Sensor Ground circuit and any other TCM circuit?
  
  Yes
  - Repair the (T820) Sensor Ground circuit for a short to another circuit.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 8

VERIFY TRANSMISSION TEMPERATURE SENSOR RESISTANCE / TEMPERATURE CORRELATION

Measure the resistance between (T54) Transmission Temperature Signal terminal and (T820) Sensor Ground terminal at the transmission temperature sensor.

TYPICAL VALUES FOR TRANSMISSION TEMPERATURE SENSOR
TEMPERATURE	APPROXIMATE RESISTANCE
-30°C (-22°F)	44000 Ohms ± 6600
10°C (50°F)	6455 Ohms ± 645
110°C (230°F)	247 Ohms ± 16
145°C (293°F)	111 Ohms ± 6

Using the chart above, compare the Temperature Sensor temperature to the correlating resistance value.

Is the resistance within the specified range when the sensor is at the given temperature?

Yes

NOTE:

If this Electronic Control Unit (ECU) is being replaced with a new unit, a diagnostic scan tool MUST be used to align the PROXI configuration data into the new ECU. Follow the routine outlined in the diagnostic scan tool for PROXI Configuration Alignment under Body Control Module (BCM) Miscellaneous Functions menu.

Using the schematics as a guide, check the Transmission Control Module (TCM) terminals and connectors for corrosion, damage or pushed out terminals. Pay particular attention to the power and ground circuits. If no problems are found, replace the TCM and perform programming and PROXI Configuration Alignment procedures. Refer to MODULE, TRANSMISSION CONTROL, REMOVAL .
Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .

Replace the Transmission Temperature Sensor in accordance with the Service Information.
Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .

CHECK WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.
4. Check for any Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the TRANSMISSION VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Test complete.