P2B71Turbocharger/Supercharger A Temperature Sensor Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2B71 covers a reading from temperature sensor A on the turbocharger or supercharger that is electrically valid yet does not fit the operating state. Typical plausibility tests compare the value after a long engine-off soak with other temperature sensors, or check it against a model; Cummins patent US8082736B2 shows how a turbine-side temperature can be derived from pressure signals, which gives the computer such a reference. CARB 13 CCR 1968.2 (e)(15.2.1) asks for two-sided rationality checks on input sensors where feasible. No manufacturer documents this code publicly, so limits and timing are unknown. Usual culprits are a drifting element, poor contact or a sensor that sits loose in its bore. Open or shorted wiring sets P2B6E to P2B70 instead; sensor B has P2B92.
- What you may notice
- Warning lamp, often without noticeable driving change
- Turbo temperature in live data differs clearly from other temperatures after a cold start
- Boost may be trimmed back as a precaution
- Likely causes
- LikelySensor element aged by heat and reading off
- PossibleContact resistance at the connector distorting the signal
- RareSensor loose or not fully seated in its bore
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.