need help O2 sensor problem
91 E34 525 M50
fault code 70 O2 sssensor circuit problem
replaced O2 twice in a 3 month period to rule out O2
i have a problem with my O2 the heater relay wont send the 12 v to the heater , but the relay is good the wiring to the O2 is good. the voltage and ground on the relay plug are good but the ecu wont close the realy . if you have dealt with this problem before please let me know.