Fuel and air

P02CA — Turbocharger/Supercharger B Overboost Condition

Severity: medium Drive with care, to a shop

What P02CA means

The engine control unit compares target boost with actual boost reported by the manifold pressure sensor. P02CA sets when boost from turbocharger or supercharger B goes above the allowed limit. Boost is normally regulated by a wastegate or variable-geometry vanes, driven by a solenoid or electric actuator. If that control fails, boost can climb out of range.

Symptoms

  • Check Engine light on
  • Reduced power or limp mode
  • Hesitation or uneven boost delivery
  • Unusual turbo whistle or noise
  • Possible engine knock under load
  • Boost spikes when you press the accelerator

Possible causes

  1. Wastegate or boost control stuck or misregulating
  2. Faulty boost pressure or MAP sensor
  3. Failed boost control solenoid
  4. Vacuum or boost hose leaks or disconnections
  5. Sticking variable-geometry mechanism
  6. Turbo actuator or position sensor fault
  7. Damaged wiring or connectors
  8. Mechanical turbocharger failure

How to diagnose

  1. Read freeze-frame data and any other codes, especially boost sensor and turbo actuator codes
  2. Compare specified and actual boost in live data at different loads
  3. Inspect vacuum lines and boost hoses for cracks, loose clamps and disconnections
  4. Check the boost and MAP sensor readings with key on, engine off
  5. Check actuator movement over its full range for binding
  6. Test the boost control solenoid: resistance, power supply and control signal
  7. Inspect wiring and connectors for corrosion or breaks
  8. Inspect the turbo for shaft play, oil in the piping and damage

Common fixes

  • Replace a faulty boost pressure sensor
  • Replace damaged vacuum or boost hoses and clamps
  • Replace the boost control solenoid or wastegate actuator
  • Repair wiring and connectors
  • Clean or replace the variable-geometry mechanism
  • Repair or replace the turbocharger

Questions and answers

What does P02CA mean?

Boost from turbocharger or supercharger B went above the allowed limit. The usual culprits are the wastegate, boost control solenoid, pressure sensor or hoses.

Can I drive with P02CA?

Only a short distance, such as to a shop, and without heavy load. Overboost can cause knock and damage the engine and turbo.

Can I just clear the code?

Clearing it may turn the light off for a while, but it will return if the fault remains. Find the cause of the overboost first.

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.