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Home DTC Codes P8091 Hard · 45-75min
P8091 Critical

OBD2 Code P8091: Powertrain System - Fault Detected

Powertrain fault detected by the computer.

ECU: BMS

Detected Root Component

Powertrain Component

Confidence level: low

Observed Symptoms

  • Hybrid fault light on
  • Loss of engine power
  • Reduced electrical autonomy

Possible Causes

  • Failed high voltage battery module
  • Damaged wiring
  • Faulty engine computer (ECU)
  • Faulty cooling system
Diagnostic Progress 0 %
Difficulty Hard
Est. time 45-75min
Tools Required 6 tool(s)

Tools Required

HV multimeter (CAT III 1000V) oscilloscope OBD scanner with hybrid/EV live data wiring diagram insulated gloves (Class 0) torque wrench

Interactive Diagnostic

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Diagnostic Result

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certainty points

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Parts likely to be the cause (Moteur (général))

Moteur (général)

Moteur (général)

Photo d'illustration : Moteur (général)

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Frequently asked questions about code P8091

What does code P8091 mean?

OBD2 Code P8091: Powertrain System - Fault Detected. Powertrain fault detected by the computer.

What are the symptoms of code P8091?

Code P8091 may cause: Hybrid fault light on, Loss of engine power, Reduced electrical autonomy. The intensity of these symptoms varies depending on the vehicle and driving conditions.

What causes code P8091?

The most common causes of code P8091 are: Failed high voltage battery module, Damaged wiring, Faulty engine computer (ECU), Faulty cooling system. A proper OBD2 diagnostic will pinpoint the exact cause.

Is it serious to drive with code P8091?

Yes, code P8091 is critical (Critical). Avoid driving and consult a professional promptly to prevent major damage.

How do I fix code P8091?

Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: Failed high voltage battery module, Damaged wiring, Faulty engine computer (ECU), Faulty cooling system. Difficulty: Hard · Estimated time: 45-75min.