Two codes, big problem

c131frdave · 01-10-2018, 12:38 PM

I'm trying to get my car through emissions testing. I've had two codes that I can see with my MHD scanner since November, but there has never been a Check Engine light until just now. I've had the ! with a triangle since November, but when the Illinois emissions people scanned the car a few days ago, they didn't have any DTCs. I assume with the Check Engine light, they will have a DTC and I'll fail.

Codes are:

2EF4 - DME: Map thermostat, mechanism
3100 - DME: Boost-pressure control, deactivation

Now, I still have boost, so I'm not sure what the second one is about. Would these DME codes throw a Check Engine light? Why would it suddenly appear after three months?

From searches, I think the first one is a failed thermostat, which sucks because I've already replaced the water pump and it was a horrible experience. The second one scares me- do you think that came in just because of the first one?

Any help would be greatly appreciated.

RocketSurgeon · 01-10-2018, 01:11 PM

Ok, the ! symbol generally just means you have the door open.
-3100 is just a limp mode code that comes up with lots of other codes. It might not necessarily be active at the moment, but limp mode was triggered at some point.
Your other code looks like a thermostat code. It could be the thermostat, or it could be the wiring harness for it. It's pretty common for the wires to get pinched.

01-10-2018, 12:38 PM	#1
c131frdave Enlisted Member 8 Rep 38 Posts Drives: 2007 335i Sedan Join Date: Feb 2016 Location: Lake in the Hills, Il iTrader: (0)	Two codes, big problem I'm trying to get my car through emissions testing. I've had two codes that I can see with my MHD scanner since November, but there has never been a Check Engine light until just now. I've had the ! with a triangle since November, but when the Illinois emissions people scanned the car a few days ago, they didn't have any DTCs. I assume with the Check Engine light, they will have a DTC and I'll fail. Codes are: 2EF4 - DME: Map thermostat, mechanism 3100 - DME: Boost-pressure control, deactivation Now, I still have boost, so I'm not sure what the second one is about. Would these DME codes throw a Check Engine light? Why would it suddenly appear after three months? From searches, I think the first one is a failed thermostat, which sucks because I've already replaced the water pump and it was a horrible experience. The second one scares me- do you think that came in just because of the first one? Any help would be greatly appreciated.
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01-10-2018, 01:11 PM	#2
RocketSurgeon Lieutenant 263 Rep 459 Posts Drives: 2008 135i Manual, CBR650F Join Date: Jan 2017 Location: NC iTrader: (0)	Ok, the ! symbol generally just means you have the door open. -3100 is just a limp mode code that comes up with lots of other codes. It might not necessarily be active at the moment, but limp mode was triggered at some point. Your other code looks like a thermostat code. It could be the thermostat, or it could be the wiring harness for it. It's pretty common for the wires to get pinched.
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