B0292HVAC A/C Compressor Clutch Circuit
- Generic OBD-II code · Body
- How the car detects it
- Whether B0292 is used anywhere is unknown; no consulted J2012 list carries it and no maker documents it. Its title points to the electromagnetic clutch that couples a belt-driven compressor to its pulley, and the relay feeding the clutch coil. Usually the engine controller owns this circuit and logs P0645–P0647; on the Saab 9-3 with Trionic 8, for instance, P0646 sets when the relay output stays below 2 V for over 1 s, and the compressor may then run without stop. Patent US20040211197A1 explains that the climate unit cannot see a failed clutch unless an extra feedback path exists, and US4481784A shows the classic battery–relay–coil chain. Electric compressors without a clutch do not use such a code.
- What you may notice
- No cooling, compressor hub does not turn with A/C on
- Compressor runs permanently even with A/C switched off
- Likely causes
- LikelyClutch coil open or shorted, often after overheating
- PossibleA/C clutch relay failed or contacts welded
- PossibleExcessive clutch air gap so the plate does not pull in
- RareClutch feed or ground wire at the compressor damaged by heat
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.