Anyone know what this fault code means?

[DakarDave]

BMW code: 235
SAE P1190

Oxygen Sensor Heater Type 2 Low Resistance Upstream

Checked for faults and got this fault code.... the beauty of a obd-II scanner!

[NoSoup4U]

From what I remember, it takes some time for the O2 sensor to warm up to work properly. During this interval, the car runs in a default mode until the O2 sensors start to work (e.g., this is why if your car is not warm you might fail emissions).

I believe the O2 sensor uses a built-in heater to reduce the time you have to wait for the sensor to warm up properly. There are 2 wires for heating, and 2 wires for sensing.

So, one of your heater wires on the O2 sensor is possibly bad. Guess it might be time to replace the O2 sensor....

I'm sure others will chime in here; but, seems like a bad heater wire = new O2 sensor.

[Shawn Fogg]

Those faults are:

BMW fault 235 = O2 sensor-heater, Post Cat. (Bank 1) Insufficient heating. "Checks the amount of time it takes to heat the o2 sensor to a predetermined limit as measured by the change in the lean signal. The test occurs during deceleration only."

A P1193 on the BMW P1 code list I have is: Post Catalyst Fuel Trim system Bank 2.

Shawn

[DakarDave]

Thanks guys....

After over 2K miles, the BMW fault 235 was the only fault code stored in the DME.... so it looks like I'm good to go and the software tuning is decent (checked AFR at dyno session).....

-Dave

[NoSoup4U]

In addition, I would check the heater wires -- it should be white. I bet you are not getting 12V to it. Thus, your DME is going to stay in open loop mode vs. closed loop. But, you should be throwing a CEL as well which it seems you are not.

What temperature is your thermostat rated at?? When was the last time it was replaced? But, it sounds like the heater circuit is not working properly.

Ahh--- a stored code...so, it's not throwing the same code when you reset the fault codes?

[DakarDave]

nope, and i haven't checked....

I'll drive around and see if it comes back.

No CEL however...

-Dave

[DakarDave]

BTW, I've never replace the thermostat or O2 sensors....

I have ~47K miles so it may be time.....

[JetBlackE46]

the CEL only comes on if it detects the same fault twice within a given period of time....