P0171 on Volvo
System Too Lean (Bank 1)
P0171 on Volvo vehicles indicates system too lean (bank 1). Au7o has documented this code across 11 Volvo models — most commonly on 240, 850, 940. This code means the engine's computer has detected that the air-fuel mixture on Bank 1 (the side of the engine with cylinder #1) is running too lean — meaning there is too much air relative to fuel. The computer watches the oxygen sensors and has had to add a large amount of extra fuel (long-term fuel trim) to try to compensate, but it has hit its correction limit. A lean condition can cause rough idle, hesitation, reduced power, and over time can run the engine hotter than normal. It usually points to either unmetered air leaking into the engine or not enough fuel being delivered. Typical repair costs on Volvo range from $30 to $6,000, depending on the specific model and root cause.
Common Causes of P0171
- •Vacuum or intake air leak (cracked hose, gasket, or PCV system)
- •Dirty or failing mass airflow (MAF) sensor
- •Weak fuel pump or restricted fuel filter
- •Clogged or dirty fuel injectors
- •Faulty or aged upstream oxygen sensor
- •Leaking intake manifold gasket
- •Low fuel pressure or failing fuel pressure regulator
- •Exhaust leak ahead of the oxygen sensor
P0171 on Volvo by Model
Volvo 240(1 issue)
- LH-Jetronic Fuel Injection and Idle Issues1990-1993
The Bosch LH-Jetronic fuel injection system develops idle problems from worn air mass meter, idle air control valve failure, and vacuum leaks. The flame trap (PCV system) clogs, causing oil leaks and rough running.
Volvo 850(1 issue)
- PCV System and Oil Trap Clogging1993-1997
The whiteblock 5-cylinder engine PCV system oil trap clogs, causing crankcase pressure buildup, oil leaks from cam seals and other gaskets, and excessive oil consumption. Must be serviced regularly.
Volvo 940(1 issue)
- PCV System Flame Trap Clogging1991-1998
The PCV flame trap (crankcase ventilation system) clogs with oil sludge, pressurizing the crankcase and causing oil leaks from every gasket and seal. This is the number one maintenance item on all redblock Volvos.
Volvo S60(1 issue)
- T5/T6 PCV Oil Trap System Failure and Oil Consumption2019-2023
The positive crankcase ventilation (PCV) system oil trap on the S60 T5 and T6 engines fails prematurely, causing excessive crankcase pressure, oil leaks, and increased oil consumption. The oil trap membrane hardens and cracks, allowing oil mist to enter the intake manifold and be burned in combustion. Failed PCV systems also cause boost leaks and rough idle. The oil trap is integrated into the valve cover on these engines, making replacement more expensive than older designs with external PCV valves. Volvo updated the oil trap design in mid-2022 production.
Volvo S70(1 issue)
- PCV System Clogging and Oil Leaks1998-2000
The Volvo S70 turbo and non-turbo 5-cylinder engines develop PCV (Positive Crankcase Ventilation) system blockage. The breather box/flame trap clogs, causing excessive crankcase pressure that pushes oil past gaskets and seals.
Volvo V50(1 issue)
- PCV Oil Trap System Failure2005-2011
The PCV oil trap system clogs or the diaphragm fails, causing excessive crankcase pressure, oil leaks from multiple gaskets, and oil consumption. This is a platform-wide issue on all Volvo 5-cylinder engines of this era.
Volvo V60(1 issue)
- T5/T6 Engine Excessive Oil Consumption2019-2023
The V60 shares the same 2.0L T5 and T6 powertrains as the S60 and XC60, and experiences the same excessive oil consumption issue. Oil consumption of 1 quart per 2,000-3,500 miles is commonly reported, particularly at sustained highway speeds. The issue is more pronounced in T6 twin-charged models due to higher combustion pressures. Volvo has issued software updates and PCV system improvements, but the fundamental piston ring design limitation persists in earlier production years.
Volvo V60 Cross Country(1 issue)
- 2.5L T5 PCV Oil Trap/Breather Box Failure2015-2018
The 2.5L turbocharged 5-cylinder engine (used in the first-gen V60 CC) has a PCV oil trap (breather box) integrated into the engine block that fails. The internal diaphragm tears, causing excessive crankcase pressure. This pushes oil past seals, causes oil leaks at multiple gaskets, and can cause turbo seal failure from the increased crankcase pressure. The PCV oil trap is located under the intake manifold and requires significant disassembly to access.
Volvo V70(1 issue)
- PCV Breather Box and Oil Trap Failure2001-2007
The P2 V70 whiteblock 5-cylinder PCV breather box and oil trap clog, causing oil leaks, turbo seal failure, and excessive oil consumption. The turbo models (T5) are especially affected as boost pressure exacerbates crankcase pressure issues.
Volvo XC60(1 issue)
- PCV Oil Trap/Separator Failure2010-2015
The Volvo XC60 with the 3.0L and 3.2L inline-6 engines develops oil trap (PCV separator) failures. The oil trap membrane degrades, causing excessive oil consumption, rough idle, and oil leaks from pressurized seals.
Volvo XC90(2 issues)
- PCV Breather System Failure2003-2014
The Positive Crankcase Ventilation (PCV) system includes a breather box and hoses that degrade over time. When the PCV fails, it causes oil leaks, rough idle, and can blow out gaskets due to excessive crankcase pressure. This is a common issue on 5-cylinder Volvos.
- Excessive Oil Consumption2015-2017
Early 2nd generation XC90s with the T6 engine may consume excessive oil between changes. Some owners report needing to add a quart every 1,500-3,000 miles. Volvo updated piston rings in later production.
Looking for P0171 on a different make?
View P0171 across all makes →Frequently Asked Questions
What does P0171 mean on Volvo?▼
P0171 stands for "System Too Lean (Bank 1)." This code means the engine's computer has detected that the air-fuel mixture on Bank 1 (the side of the engine with cylinder #1) is running too lean — meaning there is too much air relative to fuel. The computer watches the oxygen sensors and has had to add a large amount of extra fuel (long-term fuel trim) to try to compensate, but it has hit its correction limit. A lean condition can cause rough idle, hesitation, reduced power, and over time can run the engine hotter than normal. It usually points to either unmetered air leaking into the engine or not enough fuel being delivered. On Volvo specifically, this code is documented across 11 models.
What causes P0171 on Volvo vehicles?▼
Common causes on Volvo: Vacuum or intake air leak (cracked hose, gasket, or PCV system), Dirty or failing mass airflow (MAF) sensor, Weak fuel pump or restricted fuel filter, Clogged or dirty fuel injectors, Faulty or aged upstream oxygen sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0171 on a Volvo?▼
Repair costs on Volvo range from $30 to $6,000, depending on the specific model and root cause.
Which Volvo models have P0171 documented?▼
Au7o has documented P0171 on 11 Volvo models: 240, 850, 940, S60, S70, V50, V60, V60 Cross Country, V70, XC60, XC90.