P 1115 code
 

I discovered a P 1115 code when I hooked up the Durametric. No CEL, just a stored code. It reads as a fault in the bank 1 O2 sensor heating before Cat. The resistance shows 486 for that sensor, all 3 other sensors have a resistance value of 64. I'm pretty convinced the one O2 sensor is bad.

Am I missing something?

– Open circuit in sensor line
– Oxygen sensor

san rensho,

the heater resistance (between pins 1 & 2) should be less than 2.6 ohms (at 25 deg C). Is that what you were measuring?

Regards,
paul...

I was using the durametric. 3 sensors showed 64, the other sensor was around 400. I'm not sure how the durametric measures the resistance with the engine runing, but thats what the numbers were. I don't have a CEL, just a stored code which hasn't come back and no change in driveability so I'm not too concerned.

Sorry, I should have mentioned to measure this with the ignition off, and using a digital multimeter. I'm not sure what the Durametric tool will read for an actual value of the heater resistance on your car (with DME 7.2). I never explored that on my 987 (DME 7.8_40).

The O2 heater has a monitor and is checked every drive cycle and will set a permanent code (and CEL) on the 2nd drive cycle if not corrected. Since it's a stored code and you reset it, and it hasn't come back yet, you should be OK. You may want to check it in a few weeks to see if there's a stored code again.

You're right that it doesn't impact driveability -- it's only used to (as you know) to heat the O2 sensor up to its operating temperature and then shuts off.

Thx for posting your problem as it's making me curious -- I'm going to play around with my Durametric tool to see what it provides for actual values with the O2 sensors.

Regards,
paul...

Next time I'm under the car I'll measure the resistnce manually to see how it correlates with the durametric. I have a slight oil leak from the cam cover that drips onto the bad sensor, I wonder if thats whats causing it to fail.

That's possible an oil leak could cause the problem since the dialectic properties decreases as the oil gets dirty (conducts better). When testing the heater, unplug the connector from the O2 sensor.

Regards,
paul...