We have a '10 RA that we did an Evo X turbo swap in a few months ago and he just recently started getting a P2253 CEL.

heated o2 sensor offset circuit high voltage possible cause ecm failure

I checked fuel trims and they are moving normally and they are within +/- 2% at all times so I know the sensor is working fine.

Anyone come across this before and find a reason?


-Jamie
(jack_of_trades)

DP O2 sensor look good? Someone else has had this problem before.

From EvoXforums:
"The front O2 sensor is used for closed loop fueling and rear O2 testing. I personally wouldn't ignore it. I have had my car for almost 2 years and 14k miles and I have NEVER had a front O2 code. I have had like 3k rear O2 codes. If it keeps coming up, try cleaning the front O2 sensor. Autozone and O'Reilly both sell sensor safe cleaners. Running rich for extended periods could have mucked with it."

"The O2 codes reset if they haven't triggered in a while. For instance, the ECU only checks the rear O2 sensor during closed loop consistent TPS runs. If it doesn't check it in 4-5 restarts it will reset the non-volatile code. Just because the code goes away doesn't mean it is gone. With a code reader and no SES light on the display you will still get the code stored in memory to be used in emissions testing. I fought this for months and the only way I got rid of it was to wire in my wideband into my rear O2. Several months now no O2 codes. But like I said I never had a front O2 code. Give cleaning it a try, my buddy at work with his car had the same problem, only he used Dawn soap to clean it and it went away...I wouldn't recommend that."
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The sensor itself is physically fine and it's working as it should, with fuel trims exactly where they should be. This car has very low miles too.

There's a relatively new tsb that may be related, I'll pull it up later today, if possible. It involves a dealer reflash to the new 2011 rom to clean up a couple bugs, including H02S performance/interpretation.

That would be helpful, thanks

It looks like it doesn't include the code you're throwing specifically, but it is still 02 performance related due to incorrect parameters in the ECU. Here's the little bit of text to be found in the TSB:

Technical Service Bulletin
SUBJECT:
ECM REPROGRAMMING FOR
DTCS P2096, P2097, OR P0133
No: TSB−11−13−001
DATE: January, 2011
MODEL: See below

Some affected vehicles may exhibit MIL illumination with DTC P2096, P2097, or P0133 stored in the
ECM due to incorrect ECM software parameters.
This TSB provides instructions to reprogram the ECM with new parameters to correct the condition.
The O2 sensor may not be defective and should not be replaced unless the symptoms return after
reprogramming is completed, the vehicle is test driven, and further DTC diagnosis is performed.

IMPORTANT: If an affected vehicle has a Malfunction Indicator Lamp (MIL) illuminated, and DTCs
stored in the ECM other than those described in this TSB, diagnose and repair those DTCs per the
service manual before reprogramming. DO NOT reprogram the ECM until the reason for any other
DTCs being set is corrected

This is a turbocharged Lancer Ralliart anyways, thanks though.

I know that, I just realized the TSB I copied for you was the wrong one. I need to pull up the other one for you instead. I know it is legit because I used it on MY car for a P0133 that wouldn't go away.

Ahh, gotcha.

this cel has a total mind of its own it keeps going away and showing up every 3-4 days

Let's throw your original rom back in with the Evo MAF scaling for a few days and see if the CEL still gets triggered. If not, it's something with the modified rom settings that's tripping the code. If it still comes up, odds are good that there is an actual issue.

Ok, I was mistaken. When I was having my issue, it was a P2195 (stuck lean) code along with a P0133 and the TSB was for the P0133 code, but the other one went away with it...

The bulletin I was referring to was TSB-10-13-012 - ECM Reprogramming for DTC P0133 and/or Engine Idle Hunting

Damn, thanks for your efforts though! I will definitely post up what solved the issue when we figure it out.


-Jamie
aka (jack_of_trades)

Very interested to hear the solution. Sorry I couldn't be any more help.