P0171 on a Volvo: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Drivable for a short time, but a lean mixture can cause rough idling and misfires, so get it checked soon.

What P0171 means on a Volvo

On a Volvo, P0171 means bank 1 is running lean, so the engine is getting too much air or not enough fuel. The Volvo engine computer has already added as much fuel as it can and still sees a lean mixture, so it turns on the check engine light.

Is P0171 common on Volvos?

P0171 is common on Volvo's turbo 5-cylinder engines, such as the 2.4L and 2.5T in the S60, V70, and XC70. A clogged PCV system is a well-known Volvo issue that causes air to be drawn in the wrong way, and vacuum leaks from aged hoses are another frequent cause. A dirty MAF sensor also shows up on these cars.

Commonly reported on: S60, V70, XC70, S80.

Symptoms

Check engine light on
Rough or surging idle
Hesitation or lack of power
Poor fuel economy

Common causes

most common: Clogged PCV system (oil trap and hoses)
common: Vacuum leak from cracked hoses or intake boot
common: Dirty or failing mass air flow (MAF) sensor
less common: Leaking turbo intake or intercooler hose
less common: Weak fuel pump or clogged fuel filter

How to fix it

Fix	DIY?	Typical cost
Replace the PCV oil trap and hoses	Mechanic	$200–500
Inspect and replace cracked vacuum hoses	Yes	$10–80
Clean the MAF sensor with MAF cleaner spray	Yes	$10–20
Replace a weak fuel pump	Mechanic	$400–800