Fuel and air

P00CF — Barometric Pressure / Boost Sensor 'A' Correlation Fault

Severity: medium Drive with care, to a shop

What P00CF means

The engine control module compares the barometric pressure sensor with boost pressure sensor 'A'. With the engine off, or when the turbo is not making boost, both should read close to atmospheric pressure. If they differ by more than the allowed amount, the ECM sets P00CF because it can no longer trust one of the sensors.

Symptoms

  • Check Engine light on
  • Reduced power and sluggish acceleration
  • Higher fuel consumption
  • Hesitation or stumbling under throttle
  • Rough idle or stalling
  • Limp mode with limited boost

Possible causes

  1. Faulty barometric pressure (BARO) sensor
  2. Faulty boost pressure sensor 'A'
  3. Wiring or connector problems, such as corrosion or loose pins
  4. Open or short in the 5 V reference, ground or signal circuit
  5. Clogged or damaged sensor port or hose
  6. Air leak in the intake path after the turbo
  7. ECM software or calibration issue (uncommon)

How to diagnose

  1. Scan for all codes and review freeze frame data; note any other boost or sensor supply codes
  2. With key on and engine off, compare BARO and boost sensor readings in the scan tool; both should be near atmospheric pressure
  3. Check that the readings match the expected pressure for your altitude
  4. Inspect connectors and wiring at both sensors for corrosion, moisture, chafing or oil
  5. Test 5 V supply, ground and signal at each sensor with a multimeter
  6. Inspect intake piping, intercooler and hoses for cracks, oil and loose clamps
  7. Check the sensor port or vacuum line for blockage
  8. If readings disagree and wiring is good, replace the suspect sensor and retest; consider an ECM update last

Common fixes

  • Replace the barometric pressure sensor
  • Replace boost pressure sensor 'A'
  • Repair wiring and clean or replace connectors
  • Fix intake or boost leaks
  • Update or reflash the ECM per the manufacturer's bulletin

Questions and answers

What does P00CF mean?

The ECM sees that the barometric pressure sensor and boost sensor 'A' do not agree with each other. One of the sensors or its circuit is probably giving a wrong signal.

Can I drive with P00CF?

Briefly and carefully, for example to a shop. Power may be reduced, and long-term driving with bad boost data can hurt the engine and turbo.

How do I fix P00CF?

Start with the wiring and connectors, then compare both sensor readings with the engine off. Replacing the faulty BARO or boost sensor usually fixes it; an ECM reflash is rarely needed.

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.