Powertrain, generic (extended)

P2B92 Turbocharger/Supercharger B Temperature Sensor Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2B92 says that temperature sensor B delivers a plausible voltage whose content is wrong: it may hang at one value, follow load changes too slowly or disagree with its partner sensor A on an engine with two chargers. A sensor that sits in a soot-coated or oil-wetted spot reacts sluggishly and is a classic trigger. CARB 13 CCR 1968.2 (e)(15.2.1) requires such rationality tests to look for readings that are wrongly high as well as wrongly low. GM's patent US11060525B2 illustrates why the value matters: boost is reduced when the charger runs too hot, and a sensor fault switches that protection off. No manufacturer documents P2B92 publicly. Clear electrical faults use P2B8F to P2B91; sensor A has P2B71.

Likely causes

Sensor tip coated with soot or oil, responds sluggishly
Sensor element aged and reading off
Contact resistance in connector or wiring

Symptoms

  • Warning lamp, usually without drivability change
  • Sensor B lags behind or contradicts sensor A in live data
  • Boost may be limited as a precaution

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–450
Time0.5–2.5 h

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

Parts involved

turbocharger b temperature sensorwiring harnessecm

Related codes

P2B8FP2B90P2B91P2B71U0689

References: law.cornell.edu, patents.google.com, patents.google.com.