P0171 on Jaguar: How to Diagnose & Fix
System Too Lean (Bank 1)
1 Jaguar model · 1 documented issue · $400-$1,200 repair
P0171 on Jaguar by model: symptoms, diagnosis and fix
The crankcase ventilation (PCV) valve on AJ-V8 engines fails, causing excessive oil consumption, oil leaks from gaskets under positive crankcase pressure, and rough idle. The valve diaphragm tears, disrupting crankcase pressure management.
Common Symptoms
- Excessive oil consumption between changes
- Oil leaks from valve cover or front main seal
- Rough idle
- Whistling noise from engine
- Check engine light for lean codes
How to Fix
Replace the crankcase ventilation valve assembly. On the 5.0L, the pressure control valve is built into the right-hand camshaft cover; Jaguar bulletin SSM74375 now supplies a lower-level kit (C2D60163) with the rubber diaphragm and valve cover as an alternative to replacing the complete camshaft cover.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine AJ89074-type crankcase breather valve for the 4.2L branchOEMAJ89074 / W0133-1785056
Confirmed stuck/leaking crankcase vent valve on a 2009-2010 XF 4.2L V8 Fitment/availability: The genuine W0133-1785056 listing is specifically fit for 2009-2010 XF 4.2L and corresponds to the AJ89074 breather-valve family. Confirm VIN an…
- Genuine Jaguar C2D60163 PCV diaphragm-and-cap service kit for the 5.0L AJ133 branchOEMC2D60163
Confirmed torn or leaking PCV diaphragm on a compatible 2010-2015 XF 5.0L AJ133 Fitment/availability: C2D60163 is the factory diaphragm-and-cap service kit cataloged for AJ133 applications. Confirm VIN and inspect the breather housing/ho…
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Owner tips & cautions
- TipIf your V8 XF is consuming more than 1 quart per 3,000 miles, check the PCV valve before chasing other oil consumption causes. It is the most common culprit.
Sources for this issue (1)
P0171 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 P0171 mean on a Jaguar?
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 Jaguar it is documented across 1 model: XF.
What are the most common causes of P0171?
The most common causes of P0171 are: 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. The specific cause varies by vehicle.
How much does it cost to fix P0171 on a Jaguar?
Published repair estimates on Jaguar range from $400 to $1,200 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.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.