P05B1

What it means

P05B1 is the generic code for an open circuit in the control circuit of active grille air shutter 'B'. The engine or body control unit commands the shutter actuator and monitors the circuit. It has detected an open circuit, meaning the actuator or its wiring is not completing the electrical path as expected. Which shutter bank or actuator is 'B' depends on the vehicle, so check the manufacturer's information for your model.

Symptoms

• Warning light on, possibly with an active grille or engine management message
• Grille shutters stuck open or stuck closed
• Engine running hotter than usual in traffic or on a hot day if the shutters stay closed
• Slightly higher fuel consumption or more wind noise if the shutters are stuck open
• Air conditioning performing poorly at low speed if the shutters are stuck closed
• No noticeable symptoms other than the stored fault

Possible causes

• Open circuit or high resistance in the wiring between the control unit and the shutter actuatorlikely
• Corroded, loose or damaged connector at the shutter actuatorlikely
• Failed shutter actuator motor with an internal open circuitlikely
• Damage to the wiring from stone strikes, front-end repairs or rubbing on the harnesspossible
• Blown fuse or missing power or earth supply to the actuatorpossible
• Fault inside the control unit driver circuitrare

How to diagnose

1. Read all stored codes and freeze frame data, and note whether other active grille or cooling codes are present
2. Visually inspect the grille shutters for damage, debris, ice or obstruction, and check that the vanes move freely by hand where safe
3. Inspect the actuator connector and wiring for corrosion, bent pins, chafing or previous accident repair
4. Check the relevant fuse and the power and earth supplies at the actuator connector against the wiring diagram
5. Using a scan tool with bidirectional controls, command the shutter actuator and see whether it moves
6. Test the circuit continuity from the control unit to the actuator with the battery disconnected, following the manufacturer's wiring diagram
7. Measure the actuator motor resistance or compare against the manufacturer's specification, as the method depends on the model
8. Clear the code and road test to confirm it does not return

How to fix

• Repair or replace the damaged wiring section or terminal that is causing the open circuit
• Clean, secure or replace the actuator connector
• Replace the shutter actuator or shutter assembly if it has failed or is mechanically seized
• Replace the blown fuse after finding and fixing the cause of the overload
• Replace or repair the control unit only after all wiring and actuator checks pass and the manufacturer confirms a fault

Can I keep driving?

Nearby codes

• P05B0GenericActive Grille Air Shutter B Position Sensor Minimum/Maximum Stop Performance
• P05B2GenericActive Grille Air Shutter B Control Circuit Range/Performance