Fuel and air

P01C6 — Fuel Pressure Sensor A Circuit High

Severity: medium Drive with care, to a shop

What P01C6 means

The engine control unit constantly monitors the signal from fuel pressure sensor A, which normally stays within a set voltage range. P01C6 sets when the circuit voltage rises above the allowed limit. The cause can be the sensor itself, an open or shorted wire, or a real fuel pressure problem.

Symptoms

  • Check Engine Light on
  • Rough running
  • Reduced power or hesitation under load
  • Poor fuel economy
  • Hard starting or long cranking
  • No start (on high-pressure fuel systems)

Possible causes

  1. Failed fuel pressure sensor
  2. Open circuit or short to voltage or ground in the sensor wiring, corroded connector
  3. High-pressure fuel pump wear or failure
  4. Pressure regulator or volume control valve fault
  5. Weak lift pump, clogged filter or restricted low-pressure lines
  6. Excessive injector return flow
  7. Low system voltage from the battery or charging system

How to diagnose

  1. Read codes and freeze frame data, clear the code and see if it returns
  2. Inspect the sensor connector and harness for corrosion, chafing, oil or fuel contamination
  3. Compare live fuel pressure data with specification at cranking, idle and under load
  4. Check the 5 V reference and ground at the sensor connector with a multimeter
  5. Test low-pressure supply pressure and volume: pump, filter, lines
  6. Check regulator or volume control valve operation
  7. Measure injector return flow where applicable
  8. Test battery voltage and charging output

Common fixes

  • Replace the fuel pressure sensor
  • Repair wiring and connectors, fixing any short or open
  • Replace the fuel filter or lift pump if supply pressure is low
  • Repair or replace the high-pressure pump or pressure regulator
  • Replace injectors with excessive return flow

Questions and answers

What does P01C6 mean?

It means the fuel pressure sensor A circuit voltage is higher than expected. Most often the sensor or its wiring is at fault, less often the fuel system itself.

Can I drive with P01C6?

Only briefly and carefully, to a repair shop. Power loss and starting problems are possible, and on high-pressure fuel systems the engine may stall.

How do I fix P01C6?

Start by checking the sensor connector and wiring, then compare the sensor reading with actual pressure. If wiring is good and real pressure is normal, replace the sensor.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.