P05F6

Exhaust Aftertreatment Power Relay Control Circuit Stuck On

Moderate severity

The aftertreatment power relay is stuck on - aftertreatment electronics stay powered after key-off, draining the battery.

Common causes

Relay welded closed
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $90-390
Carbon or debris buildup preventing free movement
Less common, but worth ruling out after the more likely causes.
low
Typical part cost: $90-390
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P05F6.
Unlock causes
Free forever · No credit card

First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

Get the full step-by-step diagnosis

Create a free Wrenchify account to unlock the rest for P05F6.

Unlock diagnosis

Free forever · No credit card

Related codes

See related trouble codes

Create a free Wrenchify account to unlock the rest for P05F6.

Unlock related codes

Free forever · No credit card

Frequently asked questions

What does P05F6 mean?

P05F6 means "Exhaust Aftertreatment Power Relay Control Circuit Stuck On". It is a generic OBD-II code that points to a fault in the vehicle speed, idle control, auxiliary inputs.

What are the most common causes of P05F6?

relay welded closed; carbon or debris buildup preventing free movement; component wear with age - mechanical play — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

Get the full P05F6 diagnosis for your vehicle

Year, make, model + step-by-step repair help — free plan included.

Diagnose P05F6