P0172 on Nissan: How to Diagnose & Fix
System Too Rich (Bank 1)
2 Nissan models · 2 documented issues · $60-$1,200 repair
P0172 on Nissan by model: symptoms, diagnosis and fix
On 2022+ Rogues equipped with the 1.5L KR15DDT variable-compression turbo engine, owners have reported rough idle, oil odor, hesitation, and check-engine lights tied to crankcase ventilation or related air-fuel control issues. These complaints are distinct from outright transmission concerns and appear in owner forums and complaint databases as the newer engine accumulated mileage. In some cases, the issue presents as drivability problems without obvious external leaks.
Common Symptoms
- Check engine light
- Rough idle
- Oil smell from engine bay
- Hesitation on acceleration
- Poor fuel economy
- Occasional stumble after startup
How to Fix
Scan for stored engine and fuel-trim faults, inspect the PCV system and hoses for restriction or leakage, and check for intake tract leaks or oil contamination. Depending on findings, repair may involve replacing the PCV-related components, updating ECM calibration if applicable, cleaning fouled intake components, and verifying fuel trims and idle quality after repair.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Nissan PCV valve 11810-6RC0A
2022-2025 Rogue 1.5L turbo within the product's 2021-2025 fitment; confirm VIN. Not for the 2.5L engine and not a bearing-recall remedy.
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
- TipHave fuel trims and pending codes checked even if the CEL turns off; intermittent PCV or intake faults may leave useful freeze-frame data.
On the VG33E (1996+), the fuel-rail pressure damper and the fuel pressure regulator use internal diaphragms that fail with age. A ruptured diaphragm lets raw fuel weep from the damper or get drawn through the regulator vacuum line into the intake, producing a strong fuel smell, hard/long cranking hot restarts, and misfire or rich running. A simple test: run the engine a few minutes, shut off, and pull the vacuum line off the regulator/damper; fuel in the line confirms a failed diaphragm.
Common Symptoms
- Strong raw-fuel smell
- Long crank / hard start especially when hot
- Rough running or misfire
- Fuel present in the regulator/damper vacuum line
How to Fix
Replace the failed fuel pressure damper and/or fuel pressure regulator (both are inexpensive, rail-mounted, and straightforward to change). Inspect fuel-injector O-rings while the rail is accessible, since aged O-rings are a secondary source of fuel odor. Relieve fuel pressure before opening the rail.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Standard Motor Products PR95 fuel-pressure regulator
1996-1999 Pathfinder 3.3L VG33E within the product's 1996-2000 application; confirm VIN and seal requirements.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
P0172 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 P0172 mean on a Nissan?
P0172 stands for "System Too Rich (Bank 1)." P0172 means the engine computer has determined the air/fuel mixture on bank 1 is too rich — there is too much fuel relative to air. The PCM watches the oxygen sensors and fuel trims; when it must repeatedly cut back fuel to compensate for an over-rich condition and hits its correction limit, it sets this code. Bank 1 is the side of the engine containing cylinder number one. You may notice poor fuel economy, rough idle, a sulfur/rotten-egg smell, black exhaust smoke, or fouled spark plugs. On Nissan it is documented across 2 models: Rogue, Pathfinder.
What are the most common causes of P0172?
The most common causes of P0172 are: Dirty or faulty mass airflow (MAF) sensor, Leaking or stuck fuel injector, High fuel pressure (faulty regulator), Faulty oxygen sensor giving skewed readings, Clogged or dirty air filter, Leaking evaporative purge valve adding fuel vapor, Engine coolant temperature sensor reading too cold, Worn spark plugs causing inefficient combustion. The specific cause varies by vehicle.
How much does it cost to fix P0172 on a Nissan?
Published repair estimates on Nissan range from $60 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.
Looking for P0172 on a different make?
View P0172 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.