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Discussion Starter #1
Hello,

Sorry for the long post. I have a 2008 M5 with 59,700 miles. The only thing I have done is install the Evolve AlphaN tune and BMC filters over a year ago. Recently, I tried to pass emissions testing but failed due to several systems being "not ready”. Therefore, I decided to flash back to stock tune and reinstall my MAFs since I had no issues prior to the install. However, two accidents occurred while the tune was installed. One involving considerable front end damage and one that involved a little damage under the front of the car. Perhaps the tune hid some faults from the body shop who repaired it.

Anyways, after reverting to stock I cranked the hair and got a full Christmas tree. I turned it off and restarted it. Everything but the increased emissions disappeared.

I have checked all my air box connections and they are tight. I stored the MAFs in plastic bags, inside a box with packing peanuts. I tried to clear the fault with the EvolveR software. It won't clear.

Fed up and after exhausting every single search combination I could think of in the forums and the web, I decided to take a drive 270 miles to a friend in Fort Worth who happens to be a service technician at the local BMW Dealership.

He ran his BMW diagnostic software and it showed a fault but I can't remember what the code was. However, I do remember it being the IAT in Bank 1. I think it said that the "IAT Bank 1, not plausible" but I can’t be sure. He looked at the readings for the two sensors and it showed Bank 1 to read the same as Bank 2. He tried clearing the fault but it would come back. He said it was a permanent fault, meaning something is wrong. He could see that the Bank 1 MAF was getting voltage so he thought the connection might be the issue.

When I installed my IAT for AlphaN I tapped into the wires rather than cutting and soldering or crimping. Therefore, approximately half an inch of insulation has been removed from wires one and three. I taped these up but high heat degraded the tap and my friend believes they may be touching and shorting out. He popped the hood and opened the rubber covering the wires in the MAF connector from the wiring harness. He removed the tape and spread the wires far apart. He then restarted my car and was able to clear the fault. He checked the readings and it seemed to show unique values compared to Bank 1.

Fast forward the next day, if I am remembering correctly, I start my car and I see the same increased emissions fault. I drive around 400 miles on my way home and the light stays. My friend says that I should try to clear the code with my EvolveR or do a battery reset. I tried to clear the code on the EvolveR but it won’t clear. The fault code the software read was 2AFB, Intake Air Temperature Sensor Bank 1. I looked at the wires and they were still far apart. I taped them up properly and tried again. No luck. Then I unplug the battery negative cable and wait an hour. No luck. I think the ECU might be hanging on to the fault because of bad adaptive data for the Air Fuel Ratio, I have no clue if that is even a thing.

The last think I tried was to swap the MAFs. Put Bank 1 into Bank 2 and Bank 2 into Bank 1. It still says the 2AFB; however, this could just be the permanent fault that isn’t going away. However, if I can somehow clear it then if it is the MAF I would imagine that it would switch to Bank 2 Inlet Air Temperature being at fault.

Anyone have any ideas of where to go from here? Any idea how to properly do a battery reset? Any help would be much appreciated.

TL;DR: 2008 M5 giving a 2AFB fault. Fault won’t clear. Friend was able to clear it using BMW diagnostic software but it came back. Tried swapping MAFs. Still gives the same fault for the same Bank.
 

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Use data logging software and look at the live readings on your IAT and compare bank 1 and 2. Just to see whether you get reasonable readings or pure garbage. INPA may be simplest way to go.
 

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Imagine that! Problems from splicing in to the MAF harness.......

Maybe that is why my lead technician(Alfa,Astin,Bentley,Ferrari,Lambo,Lotus,Porsche etc.) REFUSES to help me do it to my car. "You may end up having to install a whole new harness group and/or tracking down untraceable electrical problems."
Sound familiar?

I REALLY want to flash my Alpha N tune, but here is another in a growing list of problems.
"You can go back and forth no problems" is not a reality.

I asked an auto electrical connection mfg. firm to have a look at the "spade into maf harness" so as to avoid splicing. Laughed out loud "They say that is a stable connection?"

We need a watertight, stable connection for the iat that plugs into the existing harness or a blanking plug and new direct dme input.


People keep telling me to "keep my MAFS in good shape" :rolleyes:
WTF does that mean?
When one was giving bad data and causing an error, I replaced it.

What I planned when I bought this car was not to spend 5digits building an engine and then stripping and splicing a factory loom critical to performance ouich
 

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Discussion Starter #4
Hello rt7085,

Do you know if the EvolveR cable will work with the INPA software? I am thinking I just need to clear all my adaption data that was gathered while the IAT was in use. I tried to clear this data in the EvolveR software but it did not seem to work. The car drove the same with no noticeable difference.

The car runs great besides this annoying light.


Thanks.
 

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One Stop Electronics Cable

Not sure. I don't have such a cable. I guess it could work. They all work the same more or less. And I bet you have successfully used it on your car already. Why don't you plug it in on a (know good) working INPA install and test it. If not, get this one:

Car Diagnostic :: By Product Type :: INPA & Ediabas :: BMW INPA / Ediabas K+DCAN USB Interface - one-stop-electronics.com

Installation Instructions for INPA:

http://www.m5board.com/vbulletin/e60-m5-e61-m5-touring-discussion/213192-successful-install-inpa-ediabas-win-7-a.html
 

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Curious if anything ever came of this? I’m having same codes now. But I haven’t spliced into mafs. I do have a regular evolve tune with eventuri intakes.


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