I got a MIL Code 1, O2 sensor voltage error

2bfi · Post by **2bfi** » Thu Mar 12, 2009 8:22 am

Tonight was the second time I got a CEL code #1. O2 sensor voltage too high or too low. The first time was a couple of weeks ago. It happened after letting off the throttle during high rpm run (7,000-7,500 rpm). The car runs fine even with the CEL on. It doesn't happen all the time, and I can't replicate the conditions that trigger it. The CEL doesn't reappear after shutting off & restarting the engine. However it stays in memory and comes out with the \"KOEO, step on throttle\" routine. I'm using a PLX M Series Wideband & JDM P30 ECU. eCtune has closeloop disabled in both Settings and Parameters/Closeloop. It doesn't seem to make any sense, isn't eCtune in control of interpreting O2 sensor voltage? Unless there is a routine built into the program to trigger code #1?

Adam Hopkins · Post by **Adam Hopkins** » Thu Mar 12, 2009 2:26 pm

What rom version are you using? I would not freak out about this, it should not be causing any problems with your car. If it comes up again then I would just continue to clear the code. I have had this happen on 1 customers car and not ever again. I think it might be an issue with wiring/ ground/ electrical system freaking out. There is no way to tell for sure what is causing it but I would try to update to the next rom version when it became available and it might solve your issues.

2bfi · Post by **2bfi** » Thu Mar 12, 2009 7:48 pm

I'm using v .63

2bfi · Post by **2bfi** » Sun Mar 15, 2009 12:16 pm

It happened again today. I caught it on datalogging. Unfortunately the log file is 4MB. The MIL went on after a prolonged deceleration. Fuel cut was active and O2 sensor voltage was 3.84V. Lambda offset correction is -0.04.

Adam Hopkins · Post by **Adam Hopkins** » Sun Mar 15, 2009 12:21 pm

Send it to Calvin attached with your cal. It might be a while before he can get to look at it but in the mean time just keep clearing the code. Make sure you tell him at what time the CEL comes on so he does not have to watch 4 MB worth of data to find it.

Bindegal · Post by **Bindegal** » Sun Mar 15, 2009 3:36 pm

Strangely enough, I have seen this happening on few (but definitely not all) customers I have running in open-loop. I have not known this to affect AFR in any way, but it is strange none the less. Apparantly thereÂ´s a little bit of code left over that can trigger the CEL 1 with closedloop disabled. /Allan

Post by **Bugermass** » Mon Mar 16, 2009 12:22 am

I have this problem on 1 car out of over 100+ that I've tuned lol.. Not sure why it is doing it but it doesn't really affect anything ...

Adam Hopkins · Post by **Adam Hopkins** » Mon Mar 16, 2009 1:12 am

It has to be some weird electrical feedback on the wiring maybe?

Post by **Bugermass** » Mon Mar 16, 2009 1:32 am

Man I must be on crack tonight, I've had to go back and edit all my posts from tonight cause I was typeing weird out of order words and what not lol.. damn A.D.D . . .

2bfi · Post by **2bfi** » Mon Mar 16, 2009 7:55 am

I sent my cal and datalog file to Calvin. He'll take a look at it when time permits.

[email protected] · Post by **[email protected]** » Fri Oct 09, 2009 9:58 pm

am also currently experiencing this phenomenon.

Post by **calvin** » Mon Oct 12, 2009 4:34 pm

2bfi wrote:It happened again today. I caught it on datalogging. Unfortunately the log file is 4MB. The MIL went on after a prolonged deceleration. Fuel cut was active and O2 sensor voltage was 3.84V. Lambda offset correction is -0.04.

send it to me please

2bfi · Post by **2bfi** » Wed Oct 14, 2009 7:51 pm

I'm posting my cal and log file here. Again, I was decelerating when the CEL went on. When I retreived the error code, it was code #1. The error comes out at 2 minutes 51.850 seconds of the datalog file.

combz · Post by **combz** » Fri Oct 16, 2009 11:54 am

i have datalogsd og this happening too. it has not happened in about 2 months..for a while it was happening alot. I dont know if its temperature related, sounds dumb, but thats about the only thing that has changed about my tune..is intake temps. ill post logs.

2bfi · Post by **2bfi** » Thu Dec 03, 2009 10:04 am

It happened again tonight.