What Does P1168 Mean?
This code indicates the fuel rail pressure sensor is reading within its operational range but at an abnormally low value that does not correlate with expected fuel system pressure under current operating conditions. Unlike a sensor circuit fault, this code means the sensor is functioning electrically but reporting low fuel pressure, suggesting an actual fueling issue or a sensor calibration problem.
Safety Warning
Low fuel pressure can cause lean misfires under load, leading to loss of power during acceleration or highway driving. This can be a safety concern in situations requiring full engine power such as merging or passing.
Common Causes
30%
Weak or failing fuel pump not generating sufficient pressure
25%
Clogged fuel filter restricting flow to the fuel rail
20%
Fuel pressure regulator stuck open or leaking, reducing rail pressure
15%
Fuel rail pressure sensor drifting out of calibration (reading low)
10%
Leaking fuel injector(s) or fuel line connection reducing system pressure
Diagnostic Steps
1
Install a mechanical fuel pressure gauge on the fuel rail test port and compare the reading to the scan tool fuel rail pressure sensor value; a significant discrepancy indicates a faulty sensor.
2
If mechanical and sensor readings agree and both are low, check fuel pump volume output (should typically deliver 0.5-1.0 L per 30 seconds) by disconnecting the fuel return line.
3
Inspect and replace the fuel filter if it has not been serviced within the maintenance interval; restricted filters commonly cause low-pressure conditions.
4
Check the fuel pressure regulator for leaking (vacuum line to regulator should not have raw fuel in it) and verify proper vacuum signal.
5
Perform a fuel system leak-down test: prime the system to operating pressure, turn off the pump, and monitor pressure decay rate.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
This code indicates the fuel rail pressure sensor is reading within its operational range but at an abnormally low value that does not correlate with expected fuel system pressure under current operating conditions. Unlike a sensor circuit fault, this code means the sensor is functioning electricall...
The most common cause of P1168 (Fuel Rail Sensor In-Range Low Failure) is: Weak or failing fuel pump not generating sufficient pressure
Typical repair costs for P1168 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Low fuel pressure can cause lean misfires under load, leading to loss of power during acceleration or highway driving. This can be a safety concern in situations requiring full engine power such as merging or passing.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1168 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Manufacturer
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