P005E: Turbocharger/Supercharger Boost Control B Supply Voltage Circuit Low

"Boost control B" is the electrically driven actuator the engine control module uses to set boost pressure: depending on the engine a pulse-width modulated solenoid or vacuum converter at the wastegate, the control valve of variable turbine vanes, or an electric actuator with position feedback. B is the second actuator, for example on the high-pressure turbocharger of a two-stage system or on the second turbocharger; it does not denote cylinder bank 2. This code concerns the supply voltage that the control module switches to the actuator (high side): it is too low, for example because of a short to ground or an open circuit. Without control the actuator usually falls back to its rest position, which on most engines means low boost; depending on the design too much boost is also possible.

Symptoms

• Check engine light on
• Loss of power or reduced power mode
• Weak acceleration, noticeable turbo lag
• Overboost possible in rare cases

Most likely causes

• Supply wire shorted to ground or interrupted
• Fuse or relay of the supply faulty
• Internal short in the actuator
• High-side driver in the engine control module faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the hoses, clamps, and intercooler
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Compare commanded and actual pressure in live data
4. Check the actuator's movement
5. Check the vacuum hoses and the solenoid valve
6. Check the oil and the turbo shaft play before replacing it

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P005E means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 0: Subsystem depends on the code range
• 5E: Specific fault in that system

Frequently asked questions

Can I keep driving with code P005E?

Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.

What causes code P005E?

The most common causes are: supply wire shorted to ground or interrupted; fuse or relay of the supply faulty; internal short in the actuator.

Related codes

• P005FTurbocharger/Supercharger Boost Control B Supply Voltage Circuit High
• P004ATurbocharger/Supercharger Boost Control B Circuit/Open
• P004CTurbocharger/Supercharger Boost Control B Circuit Low
• P006ETurbocharger/Supercharger Boost Control A Supply Voltage Circuit Low

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 14OBDG10 Engine Diagnostics
• en.wikipedia.org: Twin turbo

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.