yeah, so the DME grounds the one side of the heater- if it doesnt see current immediately, it trips a code.


I once hit some road debris and exploded the connector box on the underside of my M62... drove fine, no issues- but then the next am an immediate code. The wiring to the heater side of the O2 was open. SInce the car was warmed up and driving, the DME didnt check it untl the next cold start.


You could check for 12V on pin 4 of the pre O2. (pin 1 of post O2s)..

GL!