OBD2 Code P9999: Powertrain System - Fault Detected
Powertrain fault detected by the computer.
Detected Root Component
Powertrain Component
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
Tools Required
Interactive Diagnostic
Answer each question to calculate your diagnostic score.
No steps available.
Diagnostic Result
Score threshold guide
Was this diagnostic helpful?
Parts likely to be the cause (Moteur (général))
Moteur (général)
Photo d'illustration : Moteur (général)
© DTC-Logic.com
Click on an image to enlarge
Frequently asked questions about code P9999
What does code P9999 mean? ▾
OBD2 Code P9999: Powertrain System - Fault Detected. Powertrain fault detected by the computer.
What are the symptoms of code P9999? ▾
Code P9999 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 P9999? ▾
The most common causes of code P9999 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 P9999? ▾
Yes, code P9999 is critical (Critical). Avoid driving and consult a professional promptly to prevent major damage.
How do I fix code P9999? ▾
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: Medium · Estimated time: 30-60min.