P0193 OBD-II Trouble Code: Fuel Rail Pressure Sensor Circuit High Input
Diagnostic Trouble Code (DTC): P0193
P0193 trouble code definition
Fuel rail pressure sensor circuit high input
What the P0193 code means
The power control module (PCM) has detected that the fuel pressure is not within a range that has been predetermined by the vehicle manufacturer. When this happens the P0193 trouble code will be stored by the power control module and the Check Engine Light will come on.
What causes the P0193 code?
- Low or no fuel
- Wiring that is exposed, broken, shorted, or corroded
- Connectors that are corroded
- Fuel filter that is clogged
- Defective fuel pump relay
- Bad fuel rail sensor
- Defective fuel pump
What are the symptoms of the P0193 code?
- The Check Engine Light will come on
- The car will not start
- The car will take longer than normal to start
- The car will hesitate during acceleration
How does a mechanic diagnose the P0193 code?
The mechanic will start by inspecting the wiring and connectors for melted wires, broken wires, and corrosion. Repairing the wiring and connections if necessary.
They will use an OBD-II scanner to retrieve freeze frame data and trouble codes stored by the power control module.
They will complete a test drive, after clearing the codes, to see if the P0193 trouble code returns.
If the trouble code P0193 does not return immediately, this indicates the possibility of an intermittent issue. Intermittent problems may need to get worse before a proper diagnosis can be made.
If the car will not start, there is a possibility that there is no fuel in the fuel tank. Use a fuel pressure gauge to test the fuel pressure. Low fuel pressure is an indication that the car has little to no fuel.
To make sure the fuel pump is operating properly, the mechanic will listen to it. If the car won’t start, but they can still hear the fuel pump, the fuel injector circuitry could be faulty or a fuel filter could be clogged.
If the car won’t start and they cannot hear the fuel pump, they will try starting the car while another person taps on the bottom of the fuel tank. If the car starts, this means that the fuel pump needs to be replaced.
If the car does not start, they will check the battery voltage at the fuel pump connector. If there is no battery voltage at the fuel pump connector, they will check the fuse circuit, fuel pump relay circuit, and power control module circuit for any faults.
If these components are operational, inspect the fuel rail pressure sensor. Test the reference voltage of the fuel rail pressure sensor, using a digital volt ohmmeter, while the car is running. The voltage reading should be 5-volts. If this test is successful, test the ground wire.
If there is both a reference signal and ground signal, test the sensor resistance. If the sensor resistance test results do not meet the manufacturer’s specifications, the fuel rail pressure sensor will need to be replaced.
If the circuitry and sensors are working properly, there is a chance that the power control module is faulty. This is rare, but would require replacement and reprogramming.
Common mistakes when diagnosing the P0193 code
The most common mistake when diagnosing the P0193 trouble code is neglecting to first, check the fuel levels to make sure there is gas in the vehicle. Having no gas or low levels of gas will often cause the power control module to store this trouble code. This should be one of the first things that are inspected in addition to the other components of the fuel system before replacing the fuel rail pressure sensor.
How serious is the P0193 code?
The P0193 trouble code should be diagnosed and repaired immediately. This code is considered serious because it can cause drivability problems, such as failing or struggling to start, that makes operating the vehicle difficult, as well as dangerous.
What repairs can fix the P0193 code?
- Add fuel to the fuel tank
- Repair broken or shorted wires
- Repair corrosion of the wiring and/or connectors
- Replace clogged fuel filter
- Replace fuel pump relay
- Replace fuel pump fuse
- Replace fuel pump
- Replace fuel rail pressure sensor
Additional comments for consideration regarding the P0193 code
Before replacing the fuel pump or other components of the fuel system, make sure the car is not just out of gas. It is also important to complete all of the diagnostic steps before replacing the fuel rail pressure sensor.
Need help with a P0193 code?
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