After Cat fuel trim Error

[upallnight]

Originally Posted by Yugo

I was getting these errors on my BavAuto code reader:
E2 - After Catalytic Converter #4-6
EC - Pre Cat Fuel Trim System #4 - 6
8F - DM-TL Leak Detected
F2 - Misfire Cylinder #5

I replaced both the Pre and Post Cat O2 Sensors w/Bosch.
They are the correct ones. P/N's 15109 for Post and 13477 for Pre.

After i replaced all of the above codes went away BUT, code E2.

Any of this make more sense?

Thanks!

Depending on what type of misfire it was and how long you have been driving with the misfire, you CAT could be toast.

Did you perform the test that I suggested in my previous post.

[Yugo]

I was getting these errors on my BavAuto code reader:
E2 - After Catalytic Converter #4-6
EC - Pre Cat Fuel Trim System #4 - 6
8F - DM-TL Leak Detected
F2 - Misfire Cylinder #5

I replaced both the Pre and Post Cat O2 Sensors w/Bosch.
They are the correct ones. P/N's 15109 for Post and 13477 for Pre.

After i replaced all of the above codes went away BUT, code E2.

Any of this make more sense?

Thanks!

[Yugo]

Thanks Upallnight!

Temperature post Cat is +/- 400F
Temperature pre Cat is +/- 200F
These temps are for both banks
It's difficult to measure the pre Cat Temps.
Do these temps look about right?

Any ideas?

[Yugo]

Hello Group - Still desparately looking for some insight! Please help!!!

[bcredliner]

What was the answer to the question as to why you replaced the sensors?

[jgold47]

Originally Posted by Yugo

Hello Group - Still desparately looking for some insight! Please help!!!

Need to replace 02 sensors in pairs. Cant just do front and rear in one bank.

[David.X5]

I'm sorry, there is no clear answer to this. A couple of thoughts - just guesses...

1) The Bav Auto code reader isn't helping much. It is somehow translating several different possible BMW codes (4 digits) into one of a few 2 digit codes. Find a friend or indy shop that can read the actual BMW codes and post those.

2) post-cat O2 sensors mostly report on the health of the cat. Very few reasons one would throw a code except the O2 sensor is bad. You could try switching the left and right side post-cat O2 sensors and see if the code follows the sensor. If it does, you got a bad sensor.

3) If you get your hands on a proper BMW code reader, clear the adaptations. It is possible the engine is still trying to read the new O2 sensor based on the map it learned from your old O2 sensor.

[X53Jay4.8is]

Originally Posted by trader4

According to whom? I've replaced only one with no problems.
One had a heater failure. If it's working, it's working. If it's not
then it needs to be replaced.

+1 on the logic here.

[upallnight]

If you have an Android phone or an Android tablet, get the app Torque. Use the app features to look at the short term fuel trim and long term fuel trim in bank one and two. Yes even if you have the M54 engine, there is two banks.

This way you can determine if gas is being added to the mixture (to lean of a condition) or being taken away (too rich of a mixture). You can determine if both banks are being affected or just one bank.

[bcredliner]

Originally Posted by upallnight

If you have an Android phone or an Android tablet, get the app Torque. Use the app features to look at the short term fuel trim and long term fuel trim in bank one and two. Yes even if you have the M54 engine, there is two banks.

This way you can determine if gas is being added to the mixture (to lean of a condition) or being taken away (too rich of a mixture). You can determine if both banks are being affected or just one bank.

Past the time to step back and run thorough diagnostics.