Fault codes

[andrewc53]

I have a 90 325i and after warm up at idle i get a check engine light. It goes away at anything but idle. Code is 1222 lambda 1. Anyone know what this is. Problem 2 is brake light on the check panel. I cleaned the contacts on the box by the antenna and the light contacts as well. The lights work but the light will come on after 20 minutes of driving or so. anything else to check? Thanks a Curtis

[jlevie]

A lambda fault is either a bad O2 sensor or something that is upsetting the A/F ratio. A pre-cat O2 sensor is a maintenance item with a useful service life of not more than 100k. If that applies in this case, replace the sensor as a first step. If the Lambda fault persists after replacing the sensor, a full tune up and search for intake leaks would be the next step. The definitive test for intake leaks is to have a smoke test run.

The brake light warning will come on when the current flow through a brake light bulb circuit is less than nominal. This can be caused by:

1) Wrong bulb
2) Aged bulb
3) Bad contacts
4) Bad ground
5) Damaged wiring

Plain brass based bulbs will suffer oxidation of the brass, which increases the resistance of the bulb and thus decreases the current draw. Only use bulbs with a plated base of the correct wattage. An aged bulb that shows darkening of the glass envelope has lost material from the filament and thus its resistance has increased, requiring replacement.

[andrewc53]

jlevie, Thanks for the reply. I am in need of a o2 sensor. I did a complete tuneup and fixed any air leaks a short time ago. The car runs great. I did replace both bulbs with silver base. I'll keep looking for a problem with the wireing. Let you know if the o2 fixes it. A Curtis