Fault code P0190: Fault in fuel rail pressure sensor circuit
How to fix
Error code P0190 is described as a failure in the fuel rail pressure sensor circuit. This code closely refers to a fuel rail pressure (FRP) sensor input signal that falls below a calibrated limit over a period of time. This code may present a mechanical or electrical problem, depending largely on the vehicle manufacturer, fuel system, or fuel type.
This code is a general error code, i.e. it applies to all vehicles equipped with OBD II devices, particularly fuel injection engines, gas and diesel vehicles manufactured from 2000 to date, and manufacturers such as Ford, GMC, Volvo in general. Volvo, Volkswagen, etc. Specifications for definition, troubleshooting and repair obviously vary by make/model.
Definition
Error code P0190 appears when the PCM (powertrain control module, also known as ECM or engine control module) detects a problem with the fuel train pressure sensor, specifically its ability to stay within range. The range is determined by the manufacturer. If the PCM finds that the sensor is out of range, it activates the “Check Engine” light and records the error code.
Common Symptoms
Symptoms of this error code include
More difficult or no start
The engine turns, but it doesn’t start
The engine swings during acceleration
No power
The possible causes
The possible causes of this error code are:
Defective FRP sensor
Open circuit VREF
VREF with excessive resistance
Defective fuel pump, controller or fuel pump relay
Vacuum leakage
Clogged fuel filter
Exposed, damaged, corroded or melted cables or connectors
Little or no fuel
How to check
Mechanics diagnose this code by examining the sensor and FRP injector wiring. They will look for broken, corroded or melted wires and make repairs if necessary.
They will then use the OBD-II scanner to record free frames and other fault codes recorded in the PCM.
Once the fault codes are removed, they will take the vehicle for a test drive. If the code does not return immediately, the problem is interrupted.
However, if the code does return, the engineer continues to check the fuel gauge for pressure. If the pressure is low, there is most likely no gas. However, if the car has gas, check the fuel pump and make sure it is working properly.
If the car won’t start, but the fuel pump still works, it’s very likely that the fuel filter is clogged or that there’s a problem in the fuel injection circuits and/or the PCM.
If the fuel pump does not make any noise, check for a fault by touching the tank and try to start the car.
If the car starts successfully, it means that the fuel pump is defective and must be replaced. If the car doesn’t start, check the voltage at the fuel pump connection and check the fuel pump relay, the fuse and the PCM circuits. If all three work well, check the FRP sensor itself.
From there they will check the sensor wiring and look for signs of broken or melted wires.
They will then use their OBD II scanner to determine if the FRP sensor is still working. If the wires are checked and the FRP is still not working properly, it means that the sensor needs to be replaced.
However, in some rare cases this problem is caused by a defective PCM. The mechanic must go through advanced diagnostics to determine what is causing the problem.
How to fix
The repairs in this code are quite simple, and it can certainly indicate the necessary repairs according to the diagnosis. The most common repairs are:
Checking the fuel level and refilling the tank if necessary.
Repairing or replacing corroded connectors or pipes
Repair or replace damaged or shorted wires
Replace clogged fuel filter
Replacing the fuel pump, fuse and/or relay
Replace FRP sensor
Error code P0190 is considered a serious problem, as the ability to drive makes driving difficult and dangerous. Therefore, it definitely requires immediate attention.
In many cases the problem is caused by an empty fuel tank.