O2 sensor code (adaptation limit bank 2)

[mikey1951]

CEL on today & returned an E4 code with a Peake tool (O2 sensor adaptation limit bank 2). Which sensor is bank 2? 103K on the clock - is it time to replace all sensors? How many miles before I must replace sensor? - 65mph is about max speed of local driving ---no interstate here.

Thx guys
Mike

[rf900rkw]

That is a mixture code, not an O2.

[mikey1951]

"oxygen sensor adaptation limit #4-6 cyl" from Peake tool. It appears this is a mixture code - any advice on next step?

thx 900

[rf900rkw]

The code sets when the long term fuel trim exceeds the allowed limit. The usual suspect is a vacuum leak. There are many other possibilities ranging from a bad O2 sensor to misfires to exhaust leaks to injectors. But vacuum leaks have proven to be far and away the most popular.

And to answer your first question, Bosch calls for a life of 100K miles. Bosch is in the business of selling O2 sensors. My cars all have original sensors still at 135K. 153K, and 203K miles.

[mikey1951]

I just replaced coils & plugs a few weeks ago and all intake boots replaced a few years back. Does the #4-6 cyl part of the code give a clue? I'll give my local indy guy a call.

thx

[rf900rkw]

Yes and no. The system is split between the front three and rear three cylinders. Nominally you would think that since you only have a code for the rear, the problem would be something that effects only the rear; ruling out MAF and intake hoses and such. But the truth is the code sets when the LTFT (long term fuel trim) goes over xx% (say, 15%) two drive cycles in a row. The natural assumption is the front has to be fine because there is no code. But really it could be at 14.5%.

The equivalent code is a P1189, and the front three would be a P1188. It often happens that people will post about the one code and focus on that bank, only to have the other code surface a week later.

[mikey1951]

thx Randy - I can talk with my local wrench a little smarter now. Let you know how it all ends.

[mikey1951]

I reset the CEL & no codes for 2 days - ~ 6-8 cycles. Will monitor for a few days for future codes.

[SunzOut]

Hi, I have similar codes....

Peake tool gave me 16 CB E4

Which looks to work out as

CB "Oxygen sensor control limit, Cyl #4-6"

E4 "Oxygen sensor adaption limit, Cyl #4-6"

Going to check for vacuum leaks etc but I suspect that this would affect both banks rather than one so maybe an O2 sensor on the way out ?

Edit....

Well that did not take long...I think this would be the cause....

IMG_20160602_090145.jpg

[Bobkid]

The code sets when the long term fuel trim exceeds the allowed limit. The usual suspect is a vacuum leak. There are many other possibilities ranging from a bad O2 sensor to misfires to exhaust leaks to injectors. But vacuum leaks have proven to be far and away the most popular.

Is that code similar to the Peake reader 1b AE/AF codes I sometimes get?

AE = Mixture adaptation Cyl #1-3
AF = Mixture adaptation Cyl #4-6

Those only seem to set after a particularly bad spin at the track, and don't recur once reset.