P0174 on Jaguar
System Too Lean (Bank 2)
P0174 on Jaguar vehicles indicates system too lean (bank 2). Au7o has documented this code across 2 Jaguar models — most commonly on XF, XJ. 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 Jaguar range from $400 to $1,500, 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 Jaguar by Model
Jaguar XF(1 issue)
- Crankcase Ventilation Valve Failure on AJ-V82009-2015
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.
Jaguar XJ(1 issue)
- X350 Saddle-Tank Twin Fuel Pump / Jet Pump Failure — Stalling, Hesitation and Erratic Fuel Gauge2004-2009
The 2004-2009 X350/X358 uses a saddle-shaped fuel tank straddling the driveshaft, with a lift pump on one side and a venturi jet pump transferring fuel from the other. When the jet pump or the lift pump module degrades, the engine side of the tank runs dry even though the gauge shows fuel: owners report momentary stutters or stalls at highway speed, hard starts in cold weather, and gauges that drop suddenly or read unreliably because the level senders are built into the non-serviceable pump modules. It affects the V8 and V6 petrol cars and the 2.7 diesel. The pump module is a sealed unit so the sender is replaced with the pump.
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View P0174 across all makes →Frequently Asked Questions
What does P0174 mean on Jaguar?▼
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 Jaguar specifically, this code is documented across 2 models.
What causes P0174 on Jaguar vehicles?▼
Common causes on Jaguar: 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 Jaguar?▼
Repair costs on Jaguar range from $400 to $1,500, depending on the specific model and root cause.
Which Jaguar models have P0174 documented?▼
Au7o has documented P0174 on 2 Jaguar models: XF, XJ.