[Fiasco]

Car: LCI E90 with the N52

Odometer: 79,900 Kilometers
49,647 Miles

Mods: Completely stock



Hi all,

I recently had a tire shop swap my all seasons off of my rims and put winter tires on them. Less than 24 hours after this work was done I had the yellow emissions light and the exclamation mark in a triangle appear on the dash.

Pulled codes with ProTool and I got these initial codes, I also did some preliminary research on them:

2E98

- Alternator missing
- Check alternator voltage while running, it should be 13.6 – 14.6 volts
- Battery should be at least 12.4 volts
- Could be IBS cable
- Could be the battery itself, consider replacing if over 5 years old

2E85

- Seems to be a water pump code, potentially need to order a new water pump and thermostat.

2E81

- Water pump

2C3A

- O2 sensor

2C39

- O2 sensor

___

The final two codes are the only ones that indicated that they toggle the dash light to come on.

What should I do to troubleshoot these O2 sensor codes? I know most people go straight to replacing the sensors and I understand that that's an option, but after reading some threads it seems that some people do that and the light persists. Im looking for a trouble shooting procedure that will help me narrow down the exact cause of the light before I throw down $500+ for four new O2 sensors that are not supposed to have failed yet according to the Old School Maintenance Guide.

I cleared the codes and I plan to pull them again shortly to see which ones persist.

P.S

Temperatures have recently dropped below zero here, if that matters.

Thanks for any and all help guys.

[e91Owner]

That sounds like bus problem… like a BSD problem communicating with the DME. Have you connected ISTA to see if all of the modules are communicating?

If you're output voltage on the alternator is correct, then I would suspect that there is a common thread amongst those faults.

[Fiasco]

Originally Posted by e91Owner

That sounds like bus problem… like a BSD problem communicating with the DME. Have you connected ISTA to see if all of the modules are communicating?

If you're output voltage on the alternator is correct, then I would suspect that there is a common thread amongst those faults.

I downloaded ISTA but its not detecting my car when I plug it in, still need to troubleshoot that. Decided to buy Pro Tool in the meantime while I figure that out.

Update as of last night, the light is gone. This after clearing codes in Pro Tool. Wake up this morning, went for a drive and the light is still out. That said, im still interested in doing some trouble shooting.

What voltage should I expect from the alternator?

*Edit*

I'll also add that filling up my washer fluid took care of the exclamation mark in the triangle.

[e91Owner]

Originally Posted by Fiasco

What voltage should I expect from the alternator?

*Edit*

It should be nominally 14V. The range is +/-0.5, IIRC.