I have a 2002 Honda Stream (automatic) with the K20A engine, effectively a 7-seat long-wheelbase Civic Type-S.

After engaging reverse, the reversing sensor system has started giving the normal beep for about a second, then a constant lower note.

Apart from taking the battery off for a minute to reset the computer, can anyone tell me how to diagnose the reversing sensor system? There are no faults shown in an OBD2 reader, and the "flashing-instrument-panel-light when shorting the under-dash blue socket" method tells me nothing either.

There is supposed to be a way where you short some diagnostic wire out, then it reports the fault by beeping the error code. Does anyone know where that wire and/or the rev-sensor ECU is installed?

Thanks