Help, no power to thermostat!

scanboy · 11-07-2021, 11:32 PM

I have a 2007 e90 N51, got a code 2EF4 (DME: Map Thermostat) 4 months ago. At first I thought it was the thermostat, replaced it, still got the same code, thought the thermostat was defective, bought another one, same thing. I tested the first one I bought with a 12v, it worked, valve closed after couple minutes. I then check the connector to the thermostat with a voltmeter, I got no power when I cold started the car, the voltmeter flickered between 0v-2v. I checked the fuse (I think, cause I really don't know which one is for the thermostat), didn't find any bad ones.
Does anyone know if the e90 (N51 to be exact) has a relay to control the thermostat power? or do I have a bad DME? I'm really stuck, don't know what to do with this, the car is running too cold, only about 50 celsius (from the hidden menu). Any tips on this issue would be appreciated.

mweisdorfer · 11-17-2021, 11:33 AM

Quote:

Originally Posted by scanboy

I have a 2007 e90 N51, got a code 2EF4 (DME: Map Thermostat) 4 months ago. At first I thought it was the thermostat, replaced it, still got the same code, thought the thermostat was defective, bought another one, same thing. I tested the first one I bought with a 12v, it worked, valve closed after couple minutes. I then check the connector to the thermostat with a voltmeter, I got no power when I cold started the car, the voltmeter flickered between 0v-2v. I checked the fuse (I think, cause I really don't know which one is for the thermostat), didn't find any bad ones.
Does anyone know if the e90 (N51 to be exact) has a relay to control the thermostat power? or do I have a bad DME? I'm really stuck, don't know what to do with this, the car is running too cold, only about 50 celsius (from the hidden menu). Any tips on this issue would be appreciated.

Is the plug in damaged or the wires frayed near the plug in?

scanboy · 11-22-2021, 08:42 PM

Plug is good, I've tested with a voltmeter, both wires are good, I just don't get 12v when cold start (I assumed thermostat needs to be closes for engine to get warm faster, hence there should be 12v to the thermostat, or am I wrong?)

11-07-2021, 11:32 PM	#1
scanboy Lieutenant 16 Rep 458 Posts Drives: E90 Montego Blue+Black Int. Join Date: Sep 2007 Location: Torrance iTrader: (0)	Help, no power to thermostat! I have a 2007 e90 N51, got a code 2EF4 (DME: Map Thermostat) 4 months ago. At first I thought it was the thermostat, replaced it, still got the same code, thought the thermostat was defective, bought another one, same thing. I tested the first one I bought with a 12v, it worked, valve closed after couple minutes. I then check the connector to the thermostat with a voltmeter, I got no power when I cold started the car, the voltmeter flickered between 0v-2v. I checked the fuse (I think, cause I really don't know which one is for the thermostat), didn't find any bad ones. Does anyone know if the e90 (N51 to be exact) has a relay to control the thermostat power? or do I have a bad DME? I'm really stuck, don't know what to do with this, the car is running too cold, only about 50 celsius (from the hidden menu). Any tips on this issue would be appreciated.
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11-22-2021, 08:42 PM	#3
scanboy Lieutenant 16 Rep 458 Posts Drives: E90 Montego Blue+Black Int. Join Date: Sep 2007 Location: Torrance iTrader: (0)	Plug is good, I've tested with a voltmeter, both wires are good, I just don't get 12v when cold start (I assumed thermostat needs to be closes for engine to get warm faster, hence there should be 12v to the thermostat, or am I wrong?)
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