P0174 on Volvo: How to Diagnose & Fix
System Too Lean (Bank 2)
4 Volvo models · 5 documented issues · $50-$6,000 repair
P0174 on Volvo by model: symptoms, diagnosis and fix
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.
Common Symptoms
- Oil leaks from various gaskets
- Rough idle
- Whistling noise from engine
- Check engine light
- Oil consumption increase
- White smoke from exhaust
How to Fix
Replace the entire PCV breather box assembly along with associated hoses ($150-300 in parts). This is a common maintenance item - include it with timing belt service. DIY takes 2-4 hours. Also replace flame trap if equipped. Use OEM or quality aftermarket parts.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Volvo 8692211KT B5254T2 PCV breather-system kit
replace a pressure-tested restricted or failed five-cylinder breather box and associated hoses as a matched system Fitment/availability: 2003-2007 Volvo XC90 2.5T B5254T2 branch using oil trap 8692211 and the included coolant-pipe config…
- Genuine Volvo 31319642 B6324S PCV valve-cover oil separator
replace a diagnosed failed SI6 oil-separator/PCV assembly with the correct gasketed unit Fitment/availability: 2007-2014 Volvo XC90 3.2 B6324S/B6324S5 branch whose VIN and installed top-mounted separator confirm 31319642; excludes 2.5T f…
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Owner tips & cautions
- TipDIY repairs can save significantly - dealer charges $150-300 but DIY costs are typically 50-70% less
- TipThis is a common maintenance item - include it with timing belt service.
- TipConsider OEM parts for critical components like sensors and electrical parts - aftermarket can be unreliable
Sources for this issue (1)
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.
Common Symptoms
- Low oil warning between changes
- Need to add oil frequently
- Blue smoke on startup
- Oil smell from exhaust
How to Fix
Check oil level every 1,000 miles and top up as needed. Use Volvo-approved 0W-20 synthetic oil only. If consumption exceeds 1 quart per 1,000 miles, document with dealer for possible warranty claim. Piston ring replacement if out of warranty: $3,000-6,000. Later production engines (late 2017+) have updated rings.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Castrol Edge 32140029KT6 VCC RBS0-2AE 0W-20 oil-change kit
supply the specified oil and filter for maintenance or measured top-up while the consumption cause is documented and repaired Fitment/availability: 2016-2017 Volvo XC90 T6 B4204T27 using VCC RBS0-2AE 0W-20, Hengst filter and drain seal; …
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Owner tips & cautions
- TipDIY repairs can save significantly - dealer charges $3,000-6,000 but DIY costs are typically 50-70% less
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
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.
Common Symptoms
- Excessive oil consumption (1 qt per 2,000-3,000 miles)
- Rough idle and occasional misfires
- Oil leak from valve cover area
- Whistling noise from engine bay (boost leak through PCV)
- Check engine light with codes P0171 (lean), P0507 (idle speed high)
How to Fix
Replace the PCV oil trap assembly, which is integrated into the valve cover on these engines (Volvo part 31338685 for oil trap, or 31375560 for complete updated valve cover assembly). Clean intake manifold of oil deposits. Replace spark plugs if fouled. Use Volvo-approved 0W-20 oil and shorten oil change intervals to 5,000 miles. Updated oil trap design from mid-2022+ should be used as replacement part.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Volvo 32140004 Drive-E four-cylinder oil trap
replace a diagnosed failed crankcase oil-trap assembly Fitment/availability: Applicable non-mild-hybrid Volvo Drive-E four-cylinder S60 gasoline and plug-in-hybrid branches; confirm VIN, engine code and installed part number, and do not …
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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.
Common Symptoms
- Rough idle
- Stalling
- High idle
- Oil leaks
- Failed emissions
How to Fix
Diagnose LH-Jetronic idle problems by smoke-testing the intake for vacuum leaks, inspecting all breather/PCV hoses and the flame trap for blockage, and checking the idle air control valve for sticking or no response; also verify the air mass meter output and connector condition, as worn AMMs commonly cause unstable idle and rich running. Clean or replace the flame trap service parts and cracked vacuum hoses first, then clean the throttle body and IAC valve, and replace a faulty Bosch AMM or IAC valve if testing confirms failure. After repairs, base idle and throttle switch operation should be verified and the system rechecked for leaks and proper idle speed. Typical cost is about $50-$150 for hoses/flame trap service, $150-$350 for an IAC valve, and $250-$450 for a Bosch AMM plus 1-2 hours labor.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Volvo 114237 flame-trap kit
service a physically restricted flame-trap branch found during the idle diagnosis; not an AMM or IAC substitute Fitment/availability: 1990-1993 Volvo 240 non-turbo B230F branch; confirm installed crankcase-ventilation arrangement Fitment…
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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.
Common Symptoms
- Oil leaks from cam seals
- Blue exhaust smoke
- Oil on turbo inlet pipe
- Turbo oil leak
How to Fix
Diagnose the PCV system by checking for crankcase pressure at the oil filler cap or dipstick tube at idle; excessive pressure, whistling, or smoke from seals usually indicates a clogged oil trap/breather system. Repair requires replacing the complete PCV service kit: oil trap/breather box, hoses, banjo fittings, intake manifold gasket, and thoroughly cleaning the block breather port and related vacuum passages; on turbo models, also inspect the turbo inlet pipe and compressor housing for oil contamination and verify turbo seals were not damaged by prolonged crankcase pressure. After repair, confirm slight crankcase vacuum at idle and address any already-failed cam seals or turbo oil leaks separately if they persist. Typical cost is about $150-$300 in parts for a full kit, or roughly $600-$1,200 at an independent shop depending on labor and whether seal or turbo-related follow-up repairs are needed.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Volvo S60TURBOPCVKIT2 / 8692211 turbo PCV breather kit
replace the complete oil-trap/hoses/seals branch after confirmed PCV restriction and passage inspection Fitment/availability: Documented late-2002 through 2004 Volvo V70 turbo five-cylinder applications using the 8692211 architecture, su…
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Sources for this issue (1)
P0174 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0174 mean on a 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 it is documented across 4 models: XC90, S60, 240, V70.
What are the most common causes of P0174?
The most common causes of P0174 are: 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. The specific cause varies by vehicle.
How much does it cost to fix P0174 on a Volvo?
Published repair estimates on Volvo range from $50 to $6,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0174 on a different make?
View P0174 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.