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DTC codes / P09xx · Transmission / P0929

P0929Gear Shift Lock Solenoid Control Circuit Range/Performance

P0929 indicates that the powertrain control module (PCM) has detected an out-of-range or performance fault in the electrical circuit controlling the gear shift lock solenoid, which prevents the shifter from moving out of Park unless the brake pedal is pressed. The PCM monitors the solenoid's commanded state versus the actual circuit feedback and sets this code when the voltage or current does not match the expected values for the given conditions.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • The shift lever cannot be moved out of Park even with the brake pedal depressed.
  • The shift lock solenoid may click repeatedly or not actuate at all when the brake is pressed.
  • The brake-shift interlock override may be needed to move the vehicle.
  • Often no symptoms besides the warning light, especially if the fault is intermittent.
  • The engine may start but the vehicle cannot be driven because the shifter remains locked.
  • A buzzing or humming noise from the center console area when the ignition is on.

Common causes, most likely first

  1. Failed gear shift lock solenoid (open or shorted coil).
  2. Blown fuse or poor connection in the shift lock solenoid power circuit.
  3. Damaged or corroded wiring harness or connector at the shifter assembly.
  4. Faulty brake pedal position switch (brake light switch) not sending the release signal.
  5. Defective shift lock control module or body control module (BCM) output driver.
  6. Mechanical binding or obstruction in the shift lock mechanism.
  7. PCM internal fault or software issue (rare).

How to diagnose and fix it

  1. Verify the battery voltage and check all fuses related to the shift lock system.
  2. Inspect the shift lock solenoid connector and wiring for corrosion, damage, or loose pins.
  3. Test the brake pedal position switch operation with a scan tool or multimeter.
  4. Measure resistance and voltage at the shift lock solenoid to compare with manufacturer specifications.
  5. Check for mechanical binding in the shifter assembly and lubricate or repair as needed.
  6. If the solenoid fails electrical tests, replace the shift lock solenoid.
  7. If the circuit tests good but the PCM does not command the solenoid, diagnose the PCM or BCM and reprogram or replace as required.

Shift Lock Solenoid Circuit Quirks

  • A common oversight is assuming the solenoid itself is faulty when the real problem is a misadjusted or failed brake pedal position switch, which prevents the PCM from seeing the brake release request.
  • The code can be set by a momentary voltage spike or drop, so always check for intermittent connections and wire chafing before replacing parts.
  • On some vehicles, the shift lock solenoid is powered through the brake light circuit, so a blown brake light fuse can cause the shifter to stay locked without any brake light symptoms.
  • A binding shift lock mechanism can mimic an electrical failure by preventing the solenoid from moving fully, causing the PCM to detect a performance fault.
  • After repairs, the code may require several drive cycles with proper brake pedal application to clear from the PCM memory.

Can I keep driving with P0929?

If the vehicle can be shifted out of Park using the manual override, you may drive it to a repair shop, but avoid parking on steep inclines where the override may be difficult. Do not continue driving if the shifter cannot be moved at all, as this indicates a safety hazard.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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