P0714

P0714-TRANSMISSION TEMPERATURE SENSOR INTERMITTENT





For a complete wiring diagram consult Diagrams/Electrical

Theory of Operation


The Electrohydraulic Control Unit Assembly of the NAG1 transmission contains a temperature sensor to monitor the transmission oil temperature. This sensor is wired in series with the transmission Park/Neutral switch. The Transmission Control Module (TCM) expects to see a valid voltage level from the sensor when the shifter is in Reverse or any forward Drive position. The TCM also expects to see an open circuit condition when the shifter is in the Park or Neutral position. When the controller detects an open circuit when in Reverse or any forward drive position the DTC will set. Note: The TCM substitutes the Transmission Temperature reading with Engine Temperature due to a open circuit condition in Park or Neutral.


- When Monitored:
Continuously with the ignition on and the Transmission Temperature below 170 °C (338 °F).

- Set Condition:
When the TCM detects the Temperature sensor input changes more than 10 °C (18 °F) between each 20 mSec sensor read.







Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. Testing and Inspection


Diagnostic Test


1. CHECK WIRING AND CONNECTORS
Ignition on, engine not running.
With the scan tool, monitor the Transmission Temperature.
Apply the parking brake.
With the brakes firmly applied, place the gear selector in Drive.
While monitoring the scan tool, wiggle the wires and connectors from the TCM to the Electrohydraulic Control Unit.
Did the transmission temperature fluctuate while wiggling the wires?

Yes


- Repair the wiring and/or connectors as necessary.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Go To 2




2. CHECK IF DTC RESETS
Replace the Transmission Temperature Sensor - P/N Switch.
Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test
With the scan tool, read Transmission DTCs.
Did DTC P0714 reset?

Yes


- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM. Transmission Control Module - Description
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test


No


- Test Complete.