Short to voltage or damaged wiring in the shutter actuator supply circuit; Corroded, bent or contaminated connector pins at the actuator or control unit; Faulty active grille shutter actuator with an internal fault; Charging system fault causing system voltage to be too high; Faulty control unit driver or internal supply circuit; Outdated control unit software where the manufacturer has issued a fix.

P05B7

Active Grille Air Shutter B Supply Voltage Circuit High.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
B7: FaultThe specific fault in that area

What it means

P05B7 is a generic code meaning the control unit has detected a supply voltage that is too high in the circuit feeding active grille air shutter 'B'. The shutters open and close to manage engine cooling, air conditioning load and aerodynamics. The module monitors the supply voltage to the shutter actuator, and it set the code when the reading went above the expected range. The exact layout, and which shutter bank is 'B', varies by model.

Symptoms

Engine warning light on
Active grille shutters stuck open or stuck closed
Engine or air conditioning running hotter than normal in traffic
Slightly worse fuel economy at motorway speed
Audible clicking or buzzing from the grille actuator
Possible related shutter position or actuator codes stored

Possible causes

Short to voltage or damaged wiring in the shutter actuator supply circuitlikely
Corroded, bent or contaminated connector pins at the actuator or control unitlikely
Faulty active grille shutter actuator with an internal faultpossible
Charging system fault causing system voltage to be too highpossible
Faulty control unit driver or internal supply circuitrare
Outdated control unit software where the manufacturer has issued a fixrare

How to diagnose

Read all stored codes and freeze frame data, noting battery voltage and engine conditions when the code set, and check for other shutter or charging codes.
Visually inspect the grille shutter assembly for damage, debris, ice or a jammed vane, and check it moves freely by hand where safe.
Inspect the actuator wiring and connectors for chafing, melted insulation, water ingress, corrosion and bent pins.
Measure battery voltage with the engine off and running to confirm the charging system is within normal limits.
Use a scan tool with bi-directional control, if the model supports it, to command the shutters and watch the response and reported position.
With the connector unplugged and the ignition on, check the supply and ground at the actuator against the wiring diagram for that model for any voltage on circuits that should be unpowered.
Test the wiring for a short to a power supply and check fuse and relay condition if fitted.
Check for any manufacturer service information or software updates relevant to the vehicle.

How to fix

Repair or replace damaged wiring and renew any affected connector terminals.
Clean or replace corroded connectors and make sure they are properly seated and sealed.
Replace the active grille shutter actuator or assembly if it is faulty.
Repair the charging system if system voltage is found to be too high.
Update the control unit software only if the manufacturer lists it as a fix for this fault, and replace the control unit only after the wiring and actuator have been proven good.

Can I keep driving?

Low severity

The car can usually be driven short term, but book it in soon. Watch the temperature gauge, as shutters stuck closed can cause higher engine temperatures in hot weather or heavy traffic, and stop if it overheats.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.