P0190: Fuel rail pressure sensor circuit malfunction
The engine computer gets a missing, out-of-range or erratic signal from the fuel rail pressure sensor, so it can’t control the fuel pressure precisely. It often limits the power (limp mode), and the engine may stall or not start.
Updated
What P0190 means
On diesels with common-rail injection and petrol engines with direct injection, the fuel rail feeds the injectors at high pressure. A sensor on the rail reports the pressure, and the engine computer controls the pump and the regulator by it.
P0190 means the engine computer has found a fault in that sensor’s circuit. Without a reliable pressure reading it can’t control the injection properly, so it often limits the power (limp mode); on some cars the engine won’t start.
P0191 to P0194: implausible, low, high or intermittent
P0191 means the signal is there but doesn’t fit what the engine computer expects: that can also be a real fuel pressure problem, such as a clogged filter or a weak pump. P0192 (low) and P0193 (high) usually point to the wiring or the sensor, and P0194 to a signal that drops out.
P0191: Fuel rail pressure sensor circuit range/performance
P0192: Fuel Rail Pressure Sensor A Circuit Low
P0193: Fuel Rail Pressure Sensor A Circuit High
P0194: Fuel Rail Pressure Sensor A Circuit Intermittent/Erratic
Can I keep driving?
Drive gently
Drive gently and only as far as you need to, and have it checked soon. The engine may go into limp mode, lose power or stall, and may not restart, so avoid motorways and overtaking until it’s fixed. If you smell fuel, stop when it’s safe to do so and don’t restart the engine.
General guidance based on the code alone, not on the car’s actual condition. If in doubt, stop and ask a mechanic.
Limp mode is meant to get you to a workshop, not for normal driving: the engine can also stall and may not restart. If you smell fuel, stop when it’s safe to do so and don’t restart the engine.
Symptoms
- Limp mode, or much less power.
- Hard starting, long cranking or no start.
- Stalling or hesitation on some cars.
Common causes
- Faulty fuel rail pressure sensor. The sensor sits on the high-pressure part of the fuel system, so replacing it is a job for a workshop.
- Wiring or connector fault. Check the plug on the sensor for corrosion and a firm fit, and the wiring for chafing.
- Fault in the sensor’s supply, which it may share with other sensors. Several sensors often share one supply from the engine computer. A short in one of them can take the others down too, so other sensor codes stored at the same time point this way.
- A real fuel pressure problem, such as a weak pump or clogged filter. Mainly with P0191, where the signal is within its range but doesn’t fit.
Typical fixes
- Read all fault codes: several sensor codes together point to a shared supply.
- Check the sensor’s plug and wiring.
- Have the measured rail pressure compared with the requested pressure, and with a separate gauge where possible.
- Replace the sensor if the wiring and the supply are fine. Clear the code and check that it doesn’t come back.
Questions
Can I drive with P0190?
Gently, and only as far as you need to: the engine may go into limp mode, lose power or stall, and may not restart. Avoid motorways and overtaking until it’s fixed.
What is the difference between P0190 and P0087?
P0087 means the measured fuel pressure is too low. P0190 means the measurement itself is faulty. A faulty sensor can set P0087 too, so the pressure sensor is worth checking for both.