Code 31: Park/Neutral Switch Circuit
The park/neutral switch contacts are part of the neutral start switch. The contacts close to ground in Park or Neutral and open in Drive. Code 31 will set if circuit No. 434 indicates an open for 4 consecutive starts or if conditions occur as follows:
- No Code 38 exists.
- Circuit No. 434 indicates ground.
- Transmission is in high gear.
- TCC is locked on 4-speed only.
- Vehicle speed is greater than 45 MPH and TPS is less than 15 percent (.94 volt) on 3-speed only.
- All above conditions have been met for 12 seconds.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This tests for a closed switch to ground in Park.
- This tests for an open switch in Drive.
- Be sure "Scan" tester indicates Drive, even when wiggling shifter.