Fuel and air

P00C5 — Turbocharger B Turbine Overspeed

Severity: medium Drive with care, to a shop

What P00C5 means

The engine control module, using a turbine speed sensor or calculated data, determined that turbocharger B is spinning faster than its safe limit. Normally the wastegate or variable geometry mechanism regulates boost so turbine speed and pressure stay within range. When it is exceeded, the check engine light comes on and power is usually reduced.

Symptoms

  • Check Engine light on
  • Loss of power, especially under acceleration
  • Whistling, hissing or unusual noise from the turbo or intake
  • Limp mode activation
  • Erratic or overly aggressive boost

Possible causes

  1. Sticking or faulty wastegate actuator or variable geometry mechanism
  2. Faulty boost control solenoid or vacuum leak
  3. Failed boost pressure sensor or turbine speed sensor
  4. Damaged wiring or corroded connectors
  5. Charge air leak after the turbo
  6. Exhaust or intake restriction (clogged DPF or catalytic converter)
  7. Worn or damaged turbocharger
  8. ECM software or module fault (rare)

How to diagnose

  1. Scan all codes and freeze frame data and note any other boost-related codes
  2. Inspect hoses, pipes and vacuum lines for cracks, loose clamps and oil residue
  3. Check wiring and connectors at the boost sensors and actuator, cleaning contacts if needed
  4. Compare specified and actual boost in live data
  5. Test actuator and variable geometry movement through the full range for sticking
  6. Check the boost control solenoid and vacuum supply
  7. Test the boost pressure sensor and turbine speed sensor with a multimeter or scope
  8. Check exhaust flow and air filter condition, and check the turbo shaft for play

Common fixes

  • Replace a faulty boost pressure or turbine speed sensor
  • Repair or replace the wastegate actuator or boost control solenoid
  • Fix air and vacuum leaks and replace damaged hoses
  • Repair wiring and connectors
  • Repair or replace the turbocharger
  • Update or repair the ECM if everything else checks out

Questions and answers

What does P00C5 mean?

The ECM believes turbocharger B is spinning faster than allowed. It can be a real boost control failure or a bad sensor signal.

Can I drive with P00C5?

Only briefly and under light load until it is diagnosed. Excess turbine speed can damage the turbo.

Will clearing the code fix it?

Only temporarily. If the cause remains, the code will return and the turbo stays at risk.

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.