P0712

P0712-TRANSMISSION TEMPERATURE SENSOR LOW







Theory of Operation

The temperature sensor is used to sense the temperature of the transmission fluid. Transmission fluid temperature can affect shift quality, torque converter operation and when or if some diagnostics are run. A failed temperature sensor could affect the OBD diagnostics. If a problem occurs in the transmission temperature sensor circuit, transmission temperature will be based on a calculated value.

- When Monitored:
Continuously with the ignition on and engine running.

- Set Condition:
The DTC will set when the monitored Temperature Sensor voltage drops below 0.078 volts for the period of 1.45 seconds. When the fault is set, calculated temperature is substituted for measured temperature, however the fault code is stored only after three consecutive occurrences of the fault.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure

1. CHECK IF RELATED DTCS ARE PRESENT
1. With the scan tool, read DTCs.

Are there any Speed Sensor DTCs present?

Yes

- Refer to DTC Based Diagnostics and perform the appropriate diagnostic procedure.

No

- Go To 2

2. CHECK IF THE DTC IS CURRENT
1. With the scan tool, read DTCs.

Is the status Active or is the Starts Since Set counter 2 or less for this DTC?

Yes

- Go To 3

No

- Go To 5

3. CHECK THE PCM AND WIRING WITH THE TRANSMISSION SIMULATOR
1. Turn the ignition off to the lock position.
2. Remove the Starter Solenoid Relay from the TIPM.

CAUTION: Removal of the Starter Solenoid Relay from the TIPM will prevent the vehicle from being started in gear.

WARNING: The Starter Solenoid Relay must be removed from the TIPM. Failure to do so can result in possible serious or fatal injury.

3. Install the Transmission Simulator, Miller tool #8333A and the Electronic Transmission Adapter kit.
4. Ignition on, engine not running.
5. With the Transmission Simulator, turn the Input/Output switch to OFF.
6. With the scan tool, monitor the Transmission Temperature voltage while turning the Thermistor voltage switch to all three positions on the Transmission Simulator.
7. Compare the scan tool readings with the numbers listed on the Transmission Simulator.

Do the readings on the Transmission Simulator match the scan tool readings ± 0.2 volts?

Yes

- Replace Transmission Range Sensor (TRS) Assembly.
- Perform 42RLE TRANSMISSION VERIFICATION TEST 42RLE Transmission Verification Test

No

- Go To 4

4. CHECK THE (T54) TRANSMISSION TEMPERATURE SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Disconnect the PCM C4 harness connector.
3. Disconnect the TRS Assembly harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the PCM Pinout Box 8815 to perform diagnosis.

4. Measure the resistance between ground and the (T54) Transmission Temperature Signal circuit.

Is the resistance below 5.0 ohms?

Yes

- Repair the (T54) Transmission Temperature Signal circuit for a short to ground.
- Perform 42RLE TRANSMISSION VERIFICATION TEST 42RLE Transmission Verification Test

No

- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for Service Information Tune-ups or Service Bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM. With the scan tool, perform Quick Learn.
- Perform 42RLE TRANSMISSION VERIFICATION TEST 42RLE Transmission Verification Test

5. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set this 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. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
5. Check for any Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform 42RLE TRANSMISSION VERIFICATION TEST 42RLE Transmission Verification Test

No

- Test Complete.