Error Code P0928 is defined as Lock Solenoid/Actuator Control Circuit “A”/Open. This is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, especially those made since 1996 up to the present. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.

To prevent unintended rollaway problems, modern vehicles are equipped with gear shift lock solenoid. When the PCM (powertrain control module) detects that all of the conditions are met (brake pedal engaged, gearshift lock buttons are pressed) to shift the vehicle out of park safely, this solenoid will release and allow the transmission to shift into gear.

When Error Code P0928 appears, that means there is an electrical problem on the control circuit of the solenoid.

Common Symptoms

The most common symptom of this code is the transmission cannot shift out of park.

Possible Causes

  • Low level or dirty transmission fluid
  • Low battery voltage
  • Damaged connectors or wirings
  • Damaged fuses or fusible links
  • Faulty gearshift lock solenoid
  • Defective brake light switch

How to Check

To diagnose this code, start by examining all the related connectors and wirings in the gear shift interlock solenoid. In many cases, the problem is caused by a shorted wire or liquid damage that spilled around the shifter.

Next, check the voltage of the batter, the fuses and fusible links, and the relays. Make sure to test them all and ensure they meet the parameters.

Lastly, consider the brake lights and the condition of the transmission fluid.

How to Fix

  • Replacing the transmission fluid and filter
  • Charging or replacing the battery
  • Repair or replacement of damaged wirings and connectors
  • Replacement of blown fuses and fusible links
  • Replacement of faulty gear shift interlock solenoid
  • Replacement of faulty brake light switch

Since this code will keep the vehicle from being driven, it is a pretty serious problem that must be addressed as soon as possible.