B0237Backup Lamp Circuit
- Generic OBD-II code · Body
- How the car detects it
- Neither the publicly available J2012 lists nor any public service literature mention B0237, so it remains unconfirmed. In the words of FMVSS 108, backup lamps light the road behind the car and warn pedestrians and drivers that it is reversing or about to. HELLA notes that the circuit may only be live with the ignition on and reverse engaged. Manual gearboxes close a plunger switch in reverse; on automatics the range sensor or the transmission controller supplies the signal. In patent US5065135A, held by Automotive Products, logic that decodes the selector position energises a relay feeding the lamp for as long as reverse is reported. A fault leaves the lamps dark in reverse, or lit outside reverse when the line is shorted to supply.
- What you may notice
- Reversing lamps stay dark with reverse gear engaged
- Reversing lamps lit while driving forward
- Likely causes
- LikelyReverse light switch on the gearbox worn or its plug corroded by road spray
- PossibleReversing lamp bulb burnt out or LED unit failed
- RareMissing reverse signal from the range sensor or transmission module on automatics
- RareBroken wire in the tailgate harness feeding the lamp
- Repair
- Easy · Often possible to do yourself.Typical cost: €10 – €180
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.