P0172 on Volvo
System Too Rich (Bank 1)
P0172 on Volvo vehicles indicates system too rich (bank 1). Au7o has documented this code across 1 Volvo model — most commonly on 850. 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. Typical repair costs on Volvo range from $100 to $300, depending on the specific model and root cause.
Common Causes of P0172
- •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
P0172 on Volvo by Model
Volvo 850(1 issue)
- Fuel Pressure Regulator Diaphragm Leak1993-1997
The fuel pressure regulator (FPR) on the 850 is mounted on the fuel rail and uses a rubber diaphragm to regulate fuel pressure. The diaphragm deteriorates with age and heat exposure, allowing raw fuel to leak into the vacuum line connected to the intake manifold. This causes rich running, hard starting (especially hot), poor fuel economy, and a strong fuel smell. It can also foul spark plugs.
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What does P0172 mean on Volvo?▼
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 Volvo specifically, this code is documented across 1 model.
What causes P0172 on Volvo vehicles?▼
Common causes on Volvo: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0172 on a Volvo?▼
Repair costs on Volvo range from $100 to $300, depending on the specific model and root cause.
Which Volvo models have P0172 documented?▼
Au7o has documented P0172 on 1 Volvo model: 850.