P0191 on Audi
Fuel Rail Pressure Sensor Circuit Range/Performance
P0191 on Audi vehicles indicates fuel rail pressure sensor circuit range/performance. Au7o has documented this code across 1 Audi model — most commonly on TT. This code sets when the fuel rail pressure sensor's signal is out of its expected range or doesn't match what the computer expects for current conditions. On direct-injection and many modern engines, this sensor reports fuel pressure in the rail so the computer can precisely control fueling and the fuel pump. When the reading is implausible — too steady, erratic, or inconsistent with commanded pressure — this code is set, sometimes with hard starting, hesitation, or reduced power. It generally points to the sensor or its wiring, though an actual fuel-pressure problem can also trigger it. Typical repair costs on Audi range from $150 to $6,000, depending on the specific model and root cause.
Common Causes of P0191
- •Faulty fuel rail pressure sensor
- •Corroded, loose, or damaged sensor connector
- •Open, shorted, or high-resistance sensor wiring
- •Actual fuel pressure out of range (weak pump or regulator)
- •Restricted fuel filter or supply line
- •Loss of reference voltage or ground from the ECM/PCM
- •Faulty fuel pressure regulator or control valve
P0191 on Audi by Model
Audi TT(1 issue)
- Cam Follower Wear (Damages Camshaft and HPFP)2008-2014
The 2.0 TFSI engine in the Mk2 TT (2008-2015, particularly 2008-2009 base and 2009-2014 TTS) uses a cam follower (bucket tappet) that rides on the camshaft to drive the high-pressure fuel pump (HPFP). This follower is a wear item that can get completely ground down over time, typically by 60,000-100,000 miles. When the follower wears through, it damages the camshaft lobe and HPFP, causing catastrophic engine damage requiring camshaft replacement ($2,000-$3,000), HPFP replacement ($800-$1,500), and potentially complete cylinder head rebuild ($4,000-$6,000). Symptoms include loss of power, rough running, metallic ticking, and fuel pressure faults. This is a KNOWN DEFECT requiring preventive inspection and replacement.
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View P0191 across all makes →Frequently Asked Questions
What does P0191 mean on Audi?▼
P0191 stands for "Fuel Rail Pressure Sensor Circuit Range/Performance." This code sets when the fuel rail pressure sensor's signal is out of its expected range or doesn't match what the computer expects for current conditions. On direct-injection and many modern engines, this sensor reports fuel pressure in the rail so the computer can precisely control fueling and the fuel pump. When the reading is implausible — too steady, erratic, or inconsistent with commanded pressure — this code is set, sometimes with hard starting, hesitation, or reduced power. It generally points to the sensor or its wiring, though an actual fuel-pressure problem can also trigger it. On Audi specifically, this code is documented across 1 model.
What causes P0191 on Audi vehicles?▼
Common causes on Audi: Faulty fuel rail pressure sensor, Corroded, loose, or damaged sensor connector, Open, shorted, or high-resistance sensor wiring, Actual fuel pressure out of range (weak pump or regulator), Restricted fuel filter or supply line. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0191 on a Audi?▼
Repair costs on Audi range from $150 to $6,000, depending on the specific model and root cause.
Which Audi models have P0191 documented?▼
Au7o has documented P0191 on 1 Audi model: TT.