I have a 98 318i 4 cyl 5 spd. The check engine light comes on and indicates bank 1 slow response. Changed cat conv. And the 2 oxygen sensors. Still shows the same. Nothing seems to be the same when the light comes on (rpms, speed, hot/cold). Gets about 30 mpg and that has not changed. I am thinking something in the emission or fuel management system is intermittently changing the mixture and picked up by the front o2 sensor. Any suggestions?
Can you list the actual code that keeps turning on the MIL?
August, 29, 2006 AT 2:08 PM
P#420 is what I remember besides the description. It could be days or weeks before the check engine light comes on again. It has come on 5 times in the last 6 months. The BMW dealership were the ones who said it was isolated to the catalytic converter and O2 sensors. It is better but obviously not a complete diagnosis. The next time it comes on I will write down the complete display figures. Thanks