Mass Air Flow (MAF) Sensor and O2 sensor Adaptation Limit

[BMW1999M3FL]

I have a question - I posted it in an earlier thread. Here I provide more Information. Thank you to those who answered.

My 1999 E36 M3 has 210,000 miles. Check Engine Light (CEL) code was reading (Peake research tool) 16 08 (booklet: Air Mass sensor). I took it out and cleaned it with proper CRC MAF sensor cleaner; and let it air dry for at least 1 hour; cleared the code. It returned at every other start up. I got confirmation from Autozone as well as my own INDY mechanic who I trust fully that it is MAF sensor. So I bought a new german one Pierburg for around $200 (but not the OEM for nearly $500). I installed it, and the Air Mass code did not come back after clearing it. However, I drove for 10 miles or so, and a new CEL code displayed: 16 E3 and E4 (booklet: O2 sensor adaption limit cyl#1-3 and 4-6, respectively). I cleared the codes, and it comes back but not immediately like the MAF code. It is random and comes back intermittently.

I have two questions (especially since this is the first time I see O2 sensor adaption code; as before it was just the MAF code).

1. Could it be that the non-OEM MAF sensor is causing the issue? Is it worth buying an OEM MAF sensor before proceeding?
2. What would be best to do to address the O2 sensor codes? Smoke test for a possible air leak? any other ideas?

Please let me know if you have experienced this or know what may be the problem. I thought at first that the new MAF needs to calibrate, but the codes are coming often now. I have read elsewhere that MAF and O2 codes may be related, and some said NOT to rush to change O2 sensors since the problem may be elsewhere (as in a leak etc).

BTW: Car had intermittent hesitation when MAF was faulty, but it drives super smoothly now with the new MAF (even with the O2 codes on).

Thank you in advance,
NN

[Eric93se]

Its 100% the aftermarket mafs. I've been through this, its probably more of a m52/s52 issue, the aftermarket sensors are not following the OEM voltage output. If you can't buy new then buy used, Siemens.

I thought my car was running good but its totally not!

[BMW1999M3FL]

Thank you so much Eric!! This is very helpful!

[BMW1999M3FL]

THANK YOU THANK YOU THANK YOU!!! You are 100% accurate. As soon as I read your very confident message (especially since you've been there), I went online and bought a brand new OEM Siemens MAF sensor. Since it took 5 or so days for shipping, I decided to try a little experiment. I cleared the codes and unplugged the aftermarket (Pierburg) MAF sensor and drove for a couple of days (that was a bit nerve wracking since it hesitated a few times at the traffic lights). The only code that appeared was obviously the MAF (code 16 08). I thought perhaps this code may possibly prevent the other codes (16 E3 E4) from being triggered, but I found that not to be the case; when I plugged the Pierburg sensor back on (without cleaning the 16 08 code), the E3 and E4 codes came back on (not immediately but after a couple of days; although it drove a lot smoother than without the MAF sensor). This was even further reassurance that it is Pierburg MAF that was triggered these codes (exactly as you mentioned; possibly a voltage output mismatch).

I installed and plugged the OEM Siemens MAF sensor a week ago, and there have been no more codes after I cleared them. So many thanks Eric93se!!! I wanted to wait for a week to be sure no codes came on before I wrote this thank you message!

The mechanic that I bought the Pierburg sensor from was very kind and accepted the return and refunded me! It is a win win and a learned lesson! Your two sentences saved me a great deal of agony especially if I ended up having to diagnose an air leak that did not exist!

[Eric93se]

Awesome!

Blows my mind how aftermarket manufacturers can make such a colossal mistake.

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Earlier e36's use a different mafs so I would guess they are copying the old sensors output profile.