My 1991 850 was driving perfectly fine until it went into limp mode. Found this fault code: 201 – o2 sensor control and 70-o2 sensor circuit.
What do you think? Is it as simple as replacing an o2 sendorsement?
It could be, but I would check the signals at the wires to make sure that they are ok. You will need a wiring diagram to check it. Please let me know if you need further assistance. Thank you.