P2B91 code meaning
Turbocharger/Supercharger B Temperature Sensor Circuit High
Powertrain system Generic code P2Bxx codes Check engine light
What P2B91 means
P2B91 is stored when temperature sensor B delivers a signal above its permitted window. By far the most frequent reason is a broken current path: an unplugged or corroded connector, a cracked wire or an element that has burned open, which pulls the input up to its reference voltage. A short to the 5 V supply or to battery voltage has the same effect. For an NTC part this looks like severe cold, for a platinum resistor like severe heat; the sensor patent US8328419B2 from Heraeus explains why lead strain and heat cycling make such breaks a known weak point. No manufacturer publishes this code. Per CARB 13 CCR 1968.2 (e)(15) it is kept separate from the low fault P2B90 and the general circuit code P2B8F. Sensor A uses P2B70.
P2B91 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2B91
- Warning lamp with stored code
- Sensor B stuck at an end value in live data
Common causes of P2B91
- Most likelySignal or ground wire open, connector unplugged or corroded
- PossibleSensor element or its lead wires broken by heat cycling
- Less likelySignal wire shorted to the 5 V reference or battery voltage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Turbocharger b temperature sensorWiring harnessECM
What each part of P2B91 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| B | Area: hybrid propulsion. |
| 91 | The exact fault in that area. |
What to do next
- Note P2B91 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2B91
What does P2B91 mean?
P2B91 means "Turbocharger/Supercharger B Temperature Sensor Circuit High". P2B91 is stored when temperature sensor B delivers a signal above its permitted window. It is a generic code, so it means the same on every make.
Is it safe to drive with P2B91?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2B91 fail an emissions test?
Yes, it can. P2B91 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2B91 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will P2B91 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.