P0174 on Volvo
System Too Lean (Bank 2)
P0174 on Volvo vehicles indicates system too lean (bank 2). Au7o has documented this code across 8 Volvo models — most commonly on 240, 850, 940. P0174 means the engine computer detected that the air-fuel mixture on Bank 2 (the side of the engine with cylinder 2) is running too lean — too much air relative to fuel. The computer monitors this through the oxygen/air-fuel sensors and fuel trims; when it has to add a large amount of extra fuel to compensate and still can't reach the target, it flags the mixture as too lean. A lean condition can cause rough idle, hesitation, or misfires, and over time can raise combustion temperatures. Because it's Bank 2 specific, an unmetered air leak on that bank or a fuel delivery shortfall is typical. Typical repair costs on Volvo range from $30 to $6,000, depending on the specific model and root cause.
Common Causes of P0174
- •Vacuum or intake air leak (hoses, gaskets, PCV)
- •Dirty or failing mass airflow (MAF) sensor
- •Weak fuel pump or restricted fuel filter (low fuel pressure)
- •Clogged or underperforming fuel injectors
- •Leaking intake manifold or throttle body gasket
- •Faulty or contaminated oxygen / air-fuel sensor
- •Exhaust leak upstream of the oxygen sensor
- •Stuck-open EGR valve
P0174 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 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 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 P0174 on a different make?
View P0174 across all makes →Frequently Asked Questions
What does P0174 mean on Volvo?▼
P0174 stands for "System Too Lean (Bank 2)." P0174 means the engine computer detected that the air-fuel mixture on Bank 2 (the side of the engine with cylinder 2) is running too lean — too much air relative to fuel. The computer monitors this through the oxygen/air-fuel sensors and fuel trims; when it has to add a large amount of extra fuel to compensate and still can't reach the target, it flags the mixture as too lean. A lean condition can cause rough idle, hesitation, or misfires, and over time can raise combustion temperatures. Because it's Bank 2 specific, an unmetered air leak on that bank or a fuel delivery shortfall is typical. On Volvo specifically, this code is documented across 8 models.
What causes P0174 on Volvo vehicles?▼
Common causes on Volvo: Vacuum or intake air leak (hoses, gaskets, PCV), Dirty or failing mass airflow (MAF) sensor, Weak fuel pump or restricted fuel filter (low fuel pressure), Clogged or underperforming fuel injectors, Leaking intake manifold or throttle body gasket. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0174 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 P0174 documented?▼
Au7o has documented P0174 on 8 Volvo models: 240, 850, 940, S60, V60, V70, XC60, XC90.