P01C1

What it means

P01C1 means the engine control unit has seen the signal from the bank 2 fuel rail pressure sensor sit higher than its expected electrical range. This points to a fault in the sensor circuit, such as a short to voltage, an open ground or a faulty sensor, rather than proving the pressure itself is too high. The exact sensor layout and how bank 2 is served depend on the engine, so check the model-specific wiring information.

Symptoms

• Engine warning light on
• Reduced power or limp mode
• Hard starting or long cranking
• Rough running or hesitation under load
• Poor fuel economy
• Engine stalling or surging in some cases

Possible causes

• Faulty bank 2 fuel rail pressure sensor giving a false high signallikely
• Signal wire shorted to the 5 V reference or to a voltage supplylikely
• Open circuit in the sensor ground wire, which pushes the signal voltage highlikely
• Corroded, damaged or loose connector terminals at the sensor or control unitpossible
• Chafed or damaged wiring harness near the engine, rail or bracketspossible
• Genuinely excessive rail pressure from a fuel pressure regulation or pump fault, with a related fault loggedrare
• Internal fault in the engine control unit sensor supply or inputrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including engine speed, load and rail pressure at the time of the fault.
2. Look for related codes such as other fuel rail pressure sensor codes, 5 V reference faults or fuel pressure regulation faults, and deal with supply or reference faults first.
3. Check the live rail pressure for bank 2 with the key on and engine off, and compare it with bank 1 if fitted and with the expected value for the engine.
4. Visually inspect the sensor, connector and harness for damage, chafing, heat damage, corrosion, bent pins or water ingress.
5. With the connector unplugged, check the 5 V reference, ground and signal wire voltages against the manufacturer's wiring data for the engine.
6. Test the wiring for continuity and for shorts to voltage or ground between the sensor and control unit.
7. Wiggle the harness and connector with the engine running or the live data displayed to find an intermittent fault.
8. If the circuit tests good, check the actual fuel pressure with a suitable gauge, following model-specific safety procedures, to separate a sensor fault from a real pressure fault.

How to fix

• Repair or replace damaged wiring, including any short to voltage or open ground, and secure the harness away from heat and abrasion.
• Clean or repair corroded connector terminals, or replace the connector if the pins are damaged or loose.
• Replace the bank 2 fuel rail pressure sensor if it gives a high signal with good wiring and a good supply.
• Rectify any fuel pressure control or supply fault found if the pressure is genuinely too high.
• Have the control unit tested, and repaired or replaced, only if the sensor supply or input is proven faulty.
• Clear the code after the repair and road test to confirm it does not return.

Can I keep driving?

Nearby codes

• P01C0GenericFuel Rail Pressure Sensor Circuit Low Bank 2
• P01C2GenericFuel Rail Pressure Sensor Circuit Intermittent/Erratic Bank 2