P0191 on Cadillac
Fuel Rail Pressure Sensor Circuit Range/Performance
P0191 on Cadillac vehicles indicates fuel rail pressure sensor circuit range/performance. Au7o has documented this code across 1 Cadillac model — most commonly on XTS. 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 Cadillac range from $450 to $950, 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 Cadillac by Model
Cadillac XTS(1 issue)
- High-Pressure Direct-Injection Fuel Pump Failure2013-2019
The engine-mounted high-pressure fuel pump (HPFP) on the GM 3.6L direct-injection V6 is a known wear item that fails on the XTS, causing long crank/no-start (especially warm restart), rough idle, stalling and misfires. The most common codes are P0087 (fuel rail pressure too low), P0089 (fuel pressure regulator performance) and P0191 (rail pressure sensor), often with random misfire P0300. Because the high-pressure pump is cam-driven off the engine, a failing pump can drive adaptive fuel trims that mask early symptoms until it strands the car.
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View P0191 across all makes →Frequently Asked Questions
What does P0191 mean on Cadillac?▼
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 Cadillac specifically, this code is documented across 1 model.
What causes P0191 on Cadillac vehicles?▼
Common causes on Cadillac: 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 Cadillac?▼
Repair costs on Cadillac range from $450 to $950, depending on the specific model and root cause.
Which Cadillac models have P0191 documented?▼
Au7o has documented P0191 on 1 Cadillac model: XTS.