Diagnosing ECU code 5 IAT sensor

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• May 10, 2011

• #1

My '07 M8 has been flashing the code 5 for awhile now. It runs just fine, but I want to make it go away. The resistance checks out to the manual's specs and I have tried 2 other sensors on sleds that don't throw codes. I have checked the wiring and it seems to be fine. I get a 623ish ohm reading on the harness plug which is the same as one of the other sleds. Any ideas?

 

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• May 12, 2011

• #2

Does anybody know how the sensors are wired? It seems as though they share a common ground. That may be my problem and it would help to know a bit more about the wiring. The diagram I have just shows that one side is grounded, nothing more.

 

D

DPalmerM10

Active member

Premium Member

Jan 7, 2008

154

31

28

Crescent,OR

• May 12, 2011

• #3

Start your sled, then hold your reverse button for 15 to 30 seconds, that will make it stop sending code. :face-icon-small-coo

 

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• May 14, 2011

• #4

Cool I will try it. Is this the same as wiping the codes on a car? If there is a problem the code will come back eventually, but it might just be a fluke? Thanks for the info.

 

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• May 14, 2011

• #5

Just remembered my reverse has been stripped. I'll try and figure out if the wiring exists enough for it to work

 

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• May 16, 2011

• #6

I tried the reverse button deal and the code is still flashing. I'll keep plugging away at it.

 

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• Jan 6, 2012

• #7

Ok, so I cut off the main sheath and stripped the heat shrink at the sensor ground splice to figure out why my IAT throws a code.

1. Connection from plug to splice. OK
2. Connection from plug to ECU plug. OK
3. IAT sensor ohm's out fine
4. Plugged sensor into harness plug and punched through the wires near the actual sensor with my meter and checked again at the splice and the ECU. OK

ECU issue? What else could it be?

 

M

mutti_wilson

Free Member

Feb 20, 2008

109

22

18

La Center, WA

• Jan 9, 2012

• #8

Found an 07' ECU in the area and swapped it out and no codes. Gonna get it reflashed to the 08' map and see if that fixes it up.