P0712
P0712-TRANS TEMP SENSOR VOLTAGE TOO LOW (DIESEL)
For the Transmission circuit diagram Refer to Transmission Control Systems/Diagrams
For a complete wiring diagram refer to diagrams.
Theory of Operation
The Transmission Temperature Sensor is used to sense when the transmission temperature is too hot or too cold to operate overdrive and/or the torque convertor clutch. When the transmission sensor detects a temperature below 0°C (32°F), overdrive and the torque convertor clutch are disabled. When the detected temperature is above 1127°C (260°F), overdrive is disabled and 3rd gear with TCC is engaged, this strategy is used to increase transmission fluid flow to help cool the transmission.
- When Monitored:
Continuously with the ignition on and the engine running.
- Set Condition:
The DTC will set if the monitored Transmission Temperature Sensor Signal circuit drops below 1.55 volts for the period of 2.25 seconds.
Possible Causes
- (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND
- (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO (K900) SENSOR GROUND
- CIRCUIT
- (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND INSIDE
- TRANSMISSION
- (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO THE (K900) SENSOR GROUND
- CIRCUIT INSIDE TRANSMISSION
- TRANSMISSION TEMPERATURE SENSOR
- ENGINE CONTROL MODULE
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. CHECK IF THE DTC IS CURRENT
Ignition on, engine not running.
With the scan tool, read Engine DTCs.
Record the Freeze Frame data for the reported DTC.
With the scan tool, erase DTCs.
Turn the ignition off to the lock position.
Using the Freeze Frame data recorded earlier, try to duplicate the conditions in which the DTC originally set.
NOTE: It may be necessary to road test the vehicle to duplicate the original set conditions. With the scan tool, read Engine DTCs.
Did the DTC reset?
Yes >>Go To 2
No >>Go To 8
2. CHECK THE (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
Turn the ignition off to the lock position.
Disconnect the ECM C2 harness connector.
Disconnect the Transmission Solenoid Assembly harness connector.
NOTE: Check connectors - Clean/repair as necessary
Measure the resistance between ground and the (T54) Transmission Temperature Sensor Signal circuit in the Transmission Solenoid Assembly harness connector.
Is the resistance above 100k ohms?
Yes >>Go To 3
No >>Repair the (T54) Transmission Temperature Sensor Signal circuit for a short to ground.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
3. CHECK THE (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (T54) Transmission Temperature Sensor Signal circuit and (K900) Sensor Ground circuit in the Transmission Solenoid Assembly harness connector.
Is the resistance above 100k ohms?
Yes >>Go To 4
No >>Repair the (T54) Transmission Temperature Sensor Signal circuit for a short to the (K900) Sensor Ground circuit.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
4. CHECK THE (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND INSIDE TRANSMISSION
Remove the Transmission Oil Pan per the Service Information.
Disconnect the Governor Pressure Sensor connector internal to the transmission.
Measure the resistance between ground and the (T54) Transmission Temperature Sensor Signal circuit at the Governor Pressure Sensor connector.
Is the resistance above 100k ohms?
Yes >>Go To 5
No >>Replace the Transmission Solenoid Assembly per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
5. CHECK THE (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO (K900) SENSOR GROUND CIRCUIT INSIDE TRANSMISSION
Measure the resistance between the (T54) Transmission Temperature Sensor Signal circuit and (K900) Sensor Ground circuit at the Governor Pressure Sensor connector.
Is the resistance above 100k ohms?
Yes >>Go To 6
No >>Replace the Transmission Solenoid Assembly per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
6. TRANSMISSION TEMPERATURE SENSOR
TYPICAL VALUES FOR TRANSMISSION TEMPERATURE SENSOR
Measure the resistance of the Transmission Temperature Sensor between the (T54) Transmission Temperature Sensor Signal circuit and (K900) Sensor Ground circuit.
Using the chart above, compare the Temperature Sensor temperature to the correlating resistance value.
Is the resistance below the minimum specification for the sensor temperature?
Yes >>Replace the Governor Pressure/Transmission Temperature Sensor per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
No >>Go To 7
7. ENGINE CONTROL MODULE
Reconnect the all disconnected connectors.
Ignition on, engine not running.
With the scan tool, erase Engine DTCs.
With the scan tool, monitor Engine DTC's.
Disconnect the Transmission Temperature Sensor connector.
Did the DTC P0713 set?
Yes >>Go To 8
No >>Replace and program the Engine Control Module per the Service Information.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
8. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Use the Freeze Frame Data to help duplicate the conditions in which the DTC originally set. Pay particular attention to the DTC set conditions, such as, VSS, MAP, ECT, and Load
Using the schematics as a guide, visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
Wiggle the wiring and connectors while checking for any possible open or shorted circuits.
Check for any Service Information Tune-ups or Technical Service Bulletins that may apply.
Were there any problems found?
Yes >>Repair as necessary.
Perform RE TRANSMISSION VERIFICATION TEST VER - 1 (DIESEL). Verification Tests
No >>Test Complete.