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Any new info on your symptoms?

Mr. Dalton, will you check my new thread under Tech Help, 95 e320 Transmission Slipping? Help by Gunth Today 09:58 PM? (8-26-09) You gave me lots of info before and I hope you can do the same for this problem I'm having. Thanks.

Many thanks to AD for the O2 troubleshooting instructions on the first page.

I've had an intermittent check engine light on my '95 W124 E320 with a DTC code of 2 each time it would come up. I checked the wiring connections per the instructions and the connector had some noticeable corrosion. After cleaning both sides up, I get about 3ohms for the heater resistance (vs the 6-10 ohms specified) and did not get any voltage on pins 1 or 2 with the key in the on position. I don't get any voltage with the car running, either. No visibly worn wiring in the area.

Any other places I can check to verify that the O2 heater circuit is being powered appropriately? Can I check a certain pin on the ECU? A quick review of the fuse box reveals no blown fuses.

Well, I guess no one knows.

I'll add some additional information for posterity. An addendum to my notes and to Aurthur Dalton's instructions on the last page, the factory WIS indicates that the car needs to be idling for at least 2 minutes and have coolant temps > 80c when checking for voltage on the heater circuit. I didn't meet these criteria last time.

Under the right test conditions, I do have voltage on pins 1-2, good connection to the O2 harness itself, and 3-4 ohms of resistance on the O2 heater sensor itself. I still recently got the check engine light on a 1-hour trip. If it comes back after this latest test, I'll replace the O2 sensor on the assumption that the heater resistance is just a little too low and is falling outside of the desired test parameters.

I always clean O2 sensors with carb cleaner,let air dry,airflow sensors I use the plastic safe.

I've monitored the O2 output voltage on an OBDII car using a Scangauge and the car needs to driven 15-20 minutes to get everything hot and settled into closed loop.