P2B71 Turbocharger/Supercharger A Temperature Sensor Circuit Range/Performance

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.

Likely causes

Symptoms

• 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

Repair estimate

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

Parts involved

Related codes

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