Transmission Controls With PCM

Diagnostic Chart:

Wiring Diagram:

TRANSAXLE TEMPERATURE CIRCUIT OPEN (COLD)
The transaxle temperature circuit monitors transaxle fluid temperature by using a thermistor (sensor) located in a transaxle pressure port near the pressure filter. Sensor resistance will increase as temperature decreases and decrease as the temperature increases. The PCM supplies a five volt signal to circuit 585 and monitors the voltage on the internal signal line as it varies up and down with circuit resistance. The voltage value on the signal line is converted to a temperature value.

DTC PARAMETERS
DTC 31 is set when the PCM has detected the following conditions for longer than 30 seconds.
^ Engine run time greater than 200 seconds (3 minutes, 20 seconds.)
^ Sensor reading is -37°C (-35°F) or colder.
^ Engine coolant temp. above -17°C (1°F).

TEST DESCRIPTION
Numbered steps below refer to numbered steps on chart.

IMPORTANT: Low temperature equals high sensor resistance.

1. This step verifies the problem is still present. If Scan tool indicates temperature is greater than -37°C (-35°F) the conditions for DTC 31 are not currently present.
2. This test simulates a DTC 32 - transaxle temperature circuit grounded (hot). If the PCM recognizes the low signal (high temperature) and the Scan tool indicates temperature is greater than 140°C (284°F) the PCM and wiring are OK. Before replacing sensor, be sure that terminals on harness are clean and tight.
3. This test also simulates a DTC 32 transaxle temperature circuit grounded (hot). If the temperature reading is below 140°C (284°F) circuit 585 is open or PCM is faulty, if the temperature reading is above 140°C (284°F) circuit 586 is open or PCM is faulty. With IGN on and jumper removed, five volts at sensor harness terminal for circuit 585 indicates PCM and circuit 585 are OK.

DIAGNOSTIC AIDS
When attempting to diagnose an intermittent problem use the Scan tool* to review supplemental diagnostic information. The supplemental data can be used to duplicate a problem.

* Select MALF History from Scan tool Transmission Control Module (TCM) menu.

Check the tightness of the female terminal grip with a spare male terminal.