Powertrain, generic (extended)

P2B81 Wastegate Position Sensor A Circuit Performance

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2B81 reports that electric wastegate A does not behave as commanded although its sensor signal is electrically fine. GM documents it for the 2.7L L3B (table 19OBDG03D): with the actuator in normal operation the fault counts if the position error exceeds 20 % for over 1 s, actuator current exceeds 1.0 A for over 1 s or duty cycle exceeds 40 % for over 1 s, and 25 of 30 samples must fail; the 2025 table 25OBDG03B tightens the position limit to 10 % for 2 s with 29 of 30. It is Type A, so the MIL comes on in the first trip. GM bulletin PIP6007A names increased friction in the wastegate valve on the 2.0L LSY (Blazer, XT4 to XT6, CT4, CT5, Envision) and calls for turbocharger replacement. Wiring faults set P2AB7 to P2AB9.

Likely causes

Wastegate valve or linkage binding (GM PIP6007A, turbo replacement)

Electric wastegate actuator worn or drawing excessive current

Linkage clip missing or rod detached

Symptoms

MIL in the first trip
Boost too low or too high, flat or jerky acceleration
Reduced power mode possible

Repair estimate

DifficultyHardWorkshop job

Parts and labour€150–2,500

Time1–5 h

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

Parts involved

wastegate position sensor awastegate actuatorecm

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.