P0928Generic code

P0928 Code: Gear Shift Lock Solenoid Control Circuit/Open

The P0928 code means the shift lock solenoid control circuit is open, so the component gets no current when the computer commands it. The shifter may not come out of Park. Check the fuse, relay, connector and wiring before you replace the solenoid.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$40 to $400
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0928 code means

The shift lock solenoid keeps the lever from moving out of Park (or the shift mechanism from moving) unless the safety conditions are met, normally with the brake pedal pressed.

The computer monitors the control circuit through its own driver transistor. The P0928 code is set when the circuit is open and the component receives no current when it is commanded. Before you replace the component, check the fuse, relay, connector and wiring, because those are the most common causes.

If it fails, the lever may not come out of Park, or it may not lock at all. Many shifters have a manual emergency release. After any repair of these components you must run the transmission relearn procedures with a scan tool (clutch touch point, select and shift positions). Without them the transmission will not work properly.

Measure the resistance of the component at its connector. An infinite reading means it is open inside. If it reads correctly, follow the control wire back to the computer looking for a break, especially in the stretches near the exhaust and at intermediate connectors.

P0928 code symptoms

  • Check engine light or another warning light on.
  • The shifter will not come out of Park.
  • The transmission does not engage gears or stays in neutral.
  • Transmission or engine warning light on.
  • Beep or warning message in the instrument cluster.

Likely causes of the P0928 code

  1. Unplugged connector or one with a broken lock tab.
  2. Open coil. The resistance reads infinite.
  3. Cut wire. Check the areas where the harness rubs.
  4. Blown fuse, often because of an earlier short circuit.

How to diagnose the P0928 code step by step

  1. Command the component with the scan tool and check whether it responds.
  2. Check the fuse and the relay. Measure voltage on both sides of the fuse, and swap the relay with an identical one.
  3. Measure the supply at the connector. You should see battery voltage with the key on or when the component is commanded.
  4. Measure the resistance of the component and compare it with the manual. Also check its insulation to ground.
  5. Check the control wire. Confirm continuity all the way to the computer and make sure there is no short.
  6. Activate the actuator with the scan tool and see whether it moves.
  7. Run the transmission relearn procedures after any repair.
  8. Measure battery voltage during activation. It should not fall below 11 volts.

How to fix the P0928 code

  • Repair the connector, the wiring or the power supply.
  • Replace the shift lock solenoid if it does not respond even with correct power and control signals.
  • Clear the codes and verify the repair.

Technical reference data

  • Electric actuator (DC motor) or a hydraulic solenoid valve controlled by a PWM signal.
  • Minimum battery voltage during activation: about 11 volts.
  • Approximate values only: check the manufacturer data for your vehicle.

Brand-specific notes

This code is very common on automated manual transmissions. On many hydraulic systems the actuator fluid is a specific type and the reservoir should be checked regularly.

P0928 on Opel

Very common on the Opel Easytronic.

P0928 on Fiat

Very common on the Fiat Dualogic.

P0928 on Toyota

Very common on the Toyota MMT.

P0928 on Smart

Seen on Smart vehicles with an automated manual transmission.

P0928 on BMW

Very common on the BMW SMG.

Frequently asked questions about P0928

Can I drive with a P0928 code?
Only with caution and only as far as the shop. The transmission can lose its gears at any moment.
What does the shift lock solenoid do?
It keeps the lever from moving out of Park, or the shift mechanism from moving, unless the safety conditions are met, normally with the brake pedal pressed.
Do I always have to replace the part?
No. Check the fuses, relays, connectors and wiring first. They are the usual causes and cost much less than a new solenoid.
How much does it cost to fix P0928?
As a rough guide, between $40 and $400. A connector or wiring repair is at the low end, and a solenoid replacement costs more.
What does the P0928 code mean?
The P0928 code is a generic OBD2 code that means the shift lock solenoid control circuit is open. The component gets no current when the computer commands it.
Will a P0928 code clear itself?
Not if the circuit is still open. A cut wire or a loose connector will bring the code back whenever the solenoid is commanded.
What is the most common cause of P0928?
An unplugged connector or a cut wire. An open coil and a blown fuse follow.

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