GM OBD Trouble Code 31

Wastegate Solenoid Circuit Error

Gear Position Switch (PRNDL) Error

• Depending on the model, code 31 can refer to two different systems.
• Please choose from one of the above links for specific information on each system.
  

Wastegate Solenoid Circuit Error

The ECM regulates turbocharger boost by opening and closing the "wastegate" as necessary. (The wastegate is a vacuum operated bypass valve that limits the ability of the turbo to provide boost.) The Wastegate Solenoid regulates the vacuum supply to the wastegate for proper operation.

Fault Code Description

• 31 - Wastegate Solenoid circuit error

Symptoms

• Lack of power or engine "ping" due to overboost by the turbocharger
  

Common Problems

• The wastegate solenoid would be the most common cause for code 31 to set
• Code 31 does not indicate a problem with the turbocharger or wastegate

Gear Position Switch (PRNDL) Error

The Gear Position switch tells the ECM which position the shifter is in. The ECM will use this information to inhibit starter operation, change the transmission shift pattern as necessary, and provide the information for the electronic shift indicator display on the dash.

Fault Code Description

• 31 - Gear Position switch (PRNDL) error

Symptoms

• Engine may not crank over in Park or Neutral
• Electronic shift indicator may flash

Common Problems

A maladjusted or failed Gear Position switch would be the most common cause for a code 31