Fuel and air

P005E — Turbo/Supercharger Boost Control B Supply Voltage Low

Severity: medium Drive with care, to a shop

What P005E means

The engine control module monitors the supply voltage of boost control circuit B, which powers a turbo actuator such as a boost control solenoid or an electric vane actuator. When the voltage is lower than expected, the ECM cannot control boost accurately. It then stores P005E and turns on the check engine light. Which component belongs to circuit B depends on the vehicle, so check the wiring diagram.

Symptoms

  • Check engine light on
  • Low power and sluggish acceleration
  • Poor throttle response
  • Struggling on hills
  • Limp mode with reduced power
  • Unusual turbocharger noise

Possible causes

  1. Damaged wiring: open, short or corrosion
  2. Corroded or loose connector at the solenoid or actuator
  3. Faulty boost control solenoid or actuator
  4. Faulty turbo actuator position sensor
  5. Sticking variable geometry mechanism from soot buildup
  6. Charge-air or vacuum leak in the control system
  7. Internal ECM fault (rare)

How to diagnose

  1. Read all codes and freeze frame data, clear the code and see if it returns
  2. Inspect the harness and connectors at the boost solenoid or actuator for chafing, moisture and corrosion
  3. Check battery condition, system voltage and ground connections
  4. Measure supply voltage at the actuator connector with the key on, per the wiring diagram
  5. Test the supply and control wires for opens and shorts to ground or voltage
  6. Check the fuse and relay feeding the circuit
  7. Compare commanded and actual boost in live data
  8. Check actuator movement over its full range and inspect hoses and vacuum lines for leaks or sticking

Common fixes

  • Repair damaged wiring and connectors
  • Replace a failed fuse or relay
  • Replace the boost control solenoid or actuator
  • Clean or replace the turbo if the vane mechanism is stuck
  • Replace or reprogram the ECM only after it is confirmed faulty

Questions and answers

Can I drive with code P005E?

Only a short distance to a shop, and gently. Power is usually limited, and running with incorrect boost for long can harm the turbo and engine.

What most often causes P005E?

Wiring and connector problems in the supply circuit of the boost solenoid or actuator are the most common. The solenoid or actuator itself comes next.

Do I need a new turbo for P005E?

Usually not. Start with the power supply, wiring and actuator. The turbo is replaced only if mechanical damage or sticking is confirmed and can't be fixed.

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.