42RLE Automatic Transmission

P0712-TRANSMISSION TEMPERATURE SENSOR LOW





For a complete wiring diagram Refer to Diagrams/Electrical. Electrical Diagrams


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 42RLE Pre-Diagnostic Troubleshooting Procedure before proceeding. 42RLE - Pre-Diagnostic Troubleshooting Procedure



Diagnostic Test


1. DETERMINE IF RELATED DTC'S ARE PRESENT

With the scan tool, check Transmission DTC's.

Are there any Speed Sensor DTCs present?

Yes

- Refer to Transmission and Drivetrain and perform the appropriate test.
- Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests

No

- Go To 2



2. CHECK TO SEE IF DTC IS CURRENT

With the scan tool, Check the STARTS SINCE SET counter for P0712.


NOTE: This counter only applies to the last DTC set.

Is the STARTS SINCE SET counter 2 or less?

Yes

- Go To 3

No

- Go To 6



3. PCM AND WIRING

Turn the ignition off to the lock position.

Remove the Starter Relay.


CAUTION: Removal of the Starter Relay is to prevent a Transmission, NO RESPONSE, condition and disable the starter.

Install the Transmission Simulator, Miller tool #8333 and the Electronic Transmission Adapter kit 8333-1A.


NOTE: Check connectors - Clean/repair as necessary.

Ignition on, engine not running.

With the Transmission Simulator, turn the Input/Output switch to OFF.

With the scan tool, monitor the TRANS TEMP VOLTS while turning the Thermistor Voltage switch to all three positions on the Transmission Simulator.

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

- Go To 4

No

- Go To 5



4. TRANSMISSION TEMPERATURE SENSOR

View repair.

Repair

- Replace Transmission Solenoid/TRS Assembly.
- Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests



5. (T54) TRANSMISSION TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO GROUND





Turn the ignition off to the lock position.

Disconnect the PCM C4 harness connector.

Disconnect the TRS harness connector.


NOTE: Check connectors - Clean/repair as necessary.


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 Miller Tool #8815 to perform diagnosis.

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

Is the resistance below 5.0 ohms?

Yes

- Repair the (T54) Transmission Temperature Sensor Signal circuit for a short to ground.
- Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests

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. If no problems are found, replace the PCM. With the scan tool PERFORM QUICK LEARN, then program Pinion Factor in the Front Control Module.

- Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests



6. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set this DTC are not present at this time.

Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.

Wiggle the wires while checking for shorted and open circuits.

With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.

Were there any problems found?

Yes

- Repair as necessary.
- Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests

No

- Test Complete.