P2588 Turbo boost control position sensor: signal or voltage too low ("B")

By: Diagno editorial team · Updated: 2026-10-15

P2588 means: Turbo boost control position sensor: signal or voltage too low ("B"). The turbo pushes extra air into the engine. Drive gently and have the car checked soon. The most common repair costs about €45–90 in Estonia, depending on make and model. The most common cause: connector loose, damp or corroded.

What it means

The turbo pushes extra air into the engine. The computer found the boost pressure wrong or the turbo control not working. The car often goes into limp mode. The signal voltage is too low. Usually a wire is broken, a connector is loose or a wire is shorted to ground.

What you may notice

• Much less power (limp mode)
• Turbo whistling or hissing
• Black smoke
• Engine light on

What could be wrong

1. 1Connector loose, damp or corroded · Wiring or connector repair €45–90
2. 2Wire broken or shorted to ground · Wiring or connector repair €45–90
3. 3Faulty sensor or actuator · Sensor replacement €80–160
4. 4Engine computer fault (rare) · Control unit check and software €150–300

Repair difficulty: Hard

What you can check yourself

First look at the connector and wiring: anything loose, melted or green with corrosion? Check the boost hoses, especially the joints and around the intercooler. An oily hose points to a leak. Best left to a workshop. It needs a diagnostic tool and experience.

How we fix it

1. We read the fault data on the diagnostic tool and check whether the fault is constant
2. We measure the circuit's supply, ground and signal
3. We repair the wire or replace the connector
4. If the wiring is fine, we replace the sensor or actuator

Standard SAE description: Turbocharger Boost Control Position Sensor "B" Circuit Low