B0990Body Control Module Internal Fault
- Generic OBD-II code · Body
- How the car detects it
- For B0990 no public evidence exists, be it in J2012 lists or in carmaker or NHTSA papers. The title describes a self-detected failure inside the body control module. GM-era Saab models report this as B1000 or B101D: on the 2011 Saab 9-5 the module runs its internal test at every power-up, refuses further inputs on a fault and clears a history entry after 50 fault-free ignition cycles; a module should only be replaced if the code is current. The 9-3 BCM stores B1000 37 for an internal timeout, and its column module logs B3985 when the immobiliser code cannot be written into the BCM. TI lists open-load and short detection and fail-safe behaviour among the core BCM functions. Rule out supply and ground faults before replacing it.
- What you may notice
- Several body functions fail at once, such as lights, locks or wipers
- Car will not start if the immobiliser data cannot be read
- Code stored only as history without any noticeable effect
- Likely causes
- LikelyPoor supply voltage or ground at the module
- PossibleMoisture or corrosion inside the module
- PossibleCorrupted or outdated module software
- RareInternal electronic failure of the module
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.