Network, generic

U02B0 Lost Communication With Turbocharger/Supercharger Boost Control B Position Sensor

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

This code covers the digital position feedback of the second boost actuator. Its A counterpart, U0656, appears in GM's 2025 engine tables: the ECM reads the vane position as SENT frames and fails the link when frames stop updating for more than 6.25 ms while the line sits steadily low or high, or when message errors pile up, 480 failures in 600 samples, rated Type A (lamp on the first trip). No manufacturer documents U02B0 publicly; it applies wherever actuator B, for example on a second stage or bank, has its own sensor of this kind. Without feedback the controller can no longer hold that actuator in closed loop and falls back to a safe setting. Analog sensors use P2586 to P2590. Expect the MIL and less power.

Likely causes

Signal line or connector of the B position sensor damaged or corroded
Position sensor of actuator B failed (often integrated in the actuator)
5 V reference or ground of the sensor missing
Engine controller input damaged

Symptoms

  • Check engine lamp on the first trip
  • Reduced power, boost no longer regulated by actuator B
  • Higher smoke or emissions on diesel engines

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–1,800
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

boost control b position sensorvehicle bus wiring

Related codes

U0656U02ADP2586P2587P003B

References: gsi.ext.gm.com, patents.google.com, law.cornell.edu.