Governor Pressure Solenoid/Trans Relay Ckts (OBD II)

Name of Code:
171 ($AS - Governor Pressure Solenoid/Trans Relay Circuit

When Monitored:
Continuously with the key on.

Set Condition:
This code is set it the voltage detected on the Governor Pressure Solenoid Control Circuit at the PCM is different than the expected voltage.

Theory of Operation:
This solenoid a used to control governor pressure that the transmission needs to determine shift points. The inlet of the solenoid is exposed to transmission line pressure, the output provides regulated governor pressure to the governor circuit. Power is supplied to the solenoid by the trans control relay. The PCM provides a duty cycle signs to the solenoid to control governor pressure. The PCM grounds the control circuit to energize the solenoid. The governor pressure solenoid is normally open, therefore 0% duty cycle provides full governor pressure and 100% duty cycle would provide 0 PSI governor pressure.

Transmission effects:
The PCM turns off the transmission relay resulting in the transmission going into default mode (3rd gear). The MIL will illuminate.

Possible Causes:
- Transmission relay failure
- Open or shorted transmission relay wiring
- Open or shorted 3-4 Shift Solenoid
- Open or shorted 3-4 Shift Solenoid Control Circuit wiring
- Corroded, damaged, pushed out, miswired, or disconnected connector(s)
- Internal controller failure (PCM)