Depollution system faulty indicator on most of the time, occassionally goes off for a few days. Tried bottle of forte, went off for a while then back on. Computer diagnostics:
permanent fault. Upstream oxygen sensor open circuit
permanent fault fan assembly high speed command fault (hand written "this is working at present")
Intermittent fault upstream oxygen sensor heating command
Car drives same as always, no problem, but garage say the mix will be wrong if sensor not working.
Before we pay £255 to replace the oxygen sensor, is there anything obvious we should check that might affect this? Car done 60K, ours from new and in good nick.