P0712

Code P0712, Transaxle Temperature Sensor - Low Temp Indicated:

Intake Air Temperature (IAT), Engine Coolant Temperature (ECT), Throttle Position (TP), And Trans Temperature Sensors Wiring Schematic:

*** This information has been updated according to Technical Service Bulletin #516529, dated May 1995.

CIRCUIT DESCRIPTION
The transaxle temperature sensor uses a thermistor to vary the signal voltage to the PCM according to temperature. The PCM applies a voltage on CKT 1227 to the sensor. When the transaxle is cold the sensor resistance is high; therefore, the PCM will monitor a high signal voltage. As the transaxle warms, the sensor resistance becomes less and the voltage drops. At normal operating temperature (20°C to 90°C) the trans temp signal will measure about 2-4 volts.

DTC PO712 WILL SET WHEN:
^ Engine run time is over 2 minutes.
^ Transaxle temperature sensor signal indicates a temperature below -36°C (-33°F).
^ Above conditions for over 1.6 seconds.


ACTION TAKEN (PCM will default to):
With a current DTC P0712 set, the PCM will substitute the ECT sensor value for transaxle temperature. DTC P0712 does not illuminate the MIL (Service Engine Soon).

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Determines if conditions necessary to set DTC PO712 exist.
2. Simulates conditions to set DTC P0713. If the PCM recognizes the low signal voltage and sets DTC P0713, the wiring and PCM are OK.
3. This test will determine if CKT 1227 is open. There should be 5 volts present at the sensor connector if measured with a DVM.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check for:
^ Poor connection or damaged harness - Inspect PCM harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.
^ Intermittent test - Monitor a Tech 1 while moving related connectors and wiring harness. If the failure is induced, the scan data will change from low to high or high to low. This may help to isolate the location of the malfunction.