P2595 indicates that the turbocharger speed sensor B circuit voltage is reading below the threshold expected by the powertrain control module. This usually means the sensor signal is weak, missing, or shorted to ground, preventing accurate monitoring of turbocharger rotational speed.
The sensor’s internal Hall-effect circuitry can degrade, short, or fail, producing a signal that is permanently low or absent.
Chafed, melted, or damaged wires can short the signal or reference circuit to ground, while an open wire can cause a near-zero voltage reading.
Moisture intrusion, corrosion, or bent pins at the sensor or control module connector can introduce unwanted resistance or an effective short to ground.
If the sensor is separately serviceable, an improper mounting gap or a cracked tone wheel can reduce signal amplitude below the detection threshold.
A rare failure of the control module’s input circuit can cause a falsely low reading, but this should only be considered after the sensor and wiring are proven good.
It is not recommended. The vehicle may enter limp mode to protect the engine and turbocharger, resulting in significantly reduced power and drivability.
Usually not. The code indicates an electrical circuit fault with the speed sensor rather than a mechanical failure of the turbocharger itself, though physical damage to the turbo should be ruled out if it affected the sensor or tone wheel.
No. A failed PCM is an uncommon cause of P2595. Most faults are the sensor itself, a wiring short to ground, or a connector issue. PCM replacement should only be considered after thorough testing proves the sensor and circuit are good.
Although the sensor is the most likely component to fail, it is best to inspect the connector and wiring for corrosion or shorts before replacing parts to avoid unnecessary work.