Hi, here comes the solution, or hopefully a big part of it:
Yesterday after assembly of new Mahle thermostat (with proven 15 Ohm heater resistance), the 2ee5 error was still present. Since I changed also waterpump, damned plastics hose (Mike you we're right, the hose was also broken at the O-Ring groove) and jockey, I had 6 fault codes in the ECU. At the jockey I found a wrong plug coding issue. @MickeyMini helped me with information about the jockey versionning, but also with a schematic of X6821. I then recognized, that all the actuators on the X6821 string were showing up with acitvation fault codes.

Jockey connector coding issue

This morning measured voltage at orange wire of vanos exhaust solenoid, at orange wire at the jocky and also or wire at the thermostat. Even with car running, voltage was just 3.3V (this is btw also frequently reported by others). That led me to looking into the fuse box, and I found the F4 20A Fuse blown. Replaced that one, and after that, 6 of 7 of my ecu fault entries were history.
And 12V are back on the orange wires of the X6821.

Today I could also watch the map thermostation in action

- Without the 12V supply on the heater element, the thermostat opening happened at 112°C
-With map thermostat functionning again, the opening occurs beginning 105°C (Idle)
-When driving and giving high load, or some consequent gas pedal pushes, or 4000 rpm constant, the thermostat acts in the way to pull the temparature towards 90°C
-Bleeding the cooling system with thermostat opening at 105°C is much easier, than with non-function map thermostat opening only at 112°C, when everything is already boiling around
-Btw, a vaccum cooling system filler and also a air pump with pressure gauge was very helpful. With applied external pressure onto the system, I could press the air around the waterpump small enough, so that the cooling circuit goes round instead of just boiling mixture in the block and head

But even with such tricks, I find this car difficult to bleed.

So in the end, I think the failed map thermostat (#1) blew the F4 Fuse when it died. Why the Febi thermostat (#2) had no heater resistance, will remain a mystery. The Mahle (#3) finally does the job, and nicely came with the cable adapter from 2x2 onto 1x4 connector, which I dont need but was nice to see, and maybe I will reuse the 2x2 pin plugs later to replace a damaged one, since that plug type is widely used on this car.

So thanks to everyone who helped me during the course. I spent 3 consecutive days at the car, partly because I was also doing valve stem seals. But now am a happy man again, because ECU has not been helled and I dont need search in the wiring harness for Gremlins

BR,
ICE

 

15.5 ohm on a new Mahle at the heater. Let’s see how long this lasts

 

Outlet of thermostat going to left port at the cabin wall

http://de.minifans.info/parts-catalog/R56/Europe/One-N12/L-N/mar2009/browse/heater_and_air_conditioning/water_hoses/

br, ICE

 

I talked to Febi support some minutes ago and they stated that at the heater pins 11-14 ohm is measurable and specified. Temp sensor should be 5100 ohm at 25C.

and I will definitely check again for correct pipe in/out as you stated

Will also replace the electrical jockey and water pump, parts are ordered

thanks
ICE

 

i would check waterpump jockey wheel and coating on pulley also water pipes on these cars the hot from thermostat feeds top of radiator and top of heater matrix if wrong way around will play hell with the cooling, as far I know the thermostat heater is a simple heater neg and positive , the orange wire is constant 12v and white wire ecu switched earth

 

Hi all,

this morning I tried to measure the heater element in 3 ways (resistance, system voltage with open switched earth line and 12V externally supplied looking for current through the heater), but with every method the conclusion is, that the febi thermostat I replaced 3 weeks ago has a defect on the way to the resistor coil. And it’s been defective at least immediately after the first ignition after repair, because I wanted to see if the 2EE5 was gone but nope it was still present

ordered now a new thermostat, and the first thing I will do when it arrives, measure heater element resistance before building it into the car. Then putting the connector plug onto it and measure again

only if that all positive, then start mounting it into the car

BR, ICE

 

HI,
So today I went a bit further. Tried to measure the resistance of the heater element in the map thermostat with multimeter but always got infinite ohms. Maybe a diode in the thermostat preventing to be measured like this or the new thermostat from FEBI is crap.

Then went on with oscilloscope. I measured between orange and white lead wires in parallel Arrangement. For resistance measurement i cut the connector off, but for the scope measurement connected the leads to DME wires again and the scope in parallel.

This video shows what happened.

Scope measurement

The signal changes at coolant temp of 112°C. At 110°C the Radiator Fan Turns on. But beyond 112°C the temperature is Not dropping. Only after revving to high rpms, the tempuretaure finally drops and the osz signal changes below 112°C.

Given the recent repair history, I think in following directions:

Maybe, the map heater Is already dead
Maybe, there is still air in the coolant circuit
Maybe, the water pump is dying

What I don't understand:
At which temp should the map heated thermostat opening occur, and at which temperature should the mechanically thermostat opening without heater element, just by the coolant temp and the wax happen?

I always thought, the pure mechanical thermostat opening should take place at 105°C, and the heater element driven opening is for openings ar lower temp like 95°C, but when Motor load is suddenly increased.

So why the heck it does not cool down even when 115°C are reached
Strange to me.

Thanks if you can support me here a bit

BR,ICE

 

Can the heater element be activated by INPA or ISTA+ ?

BR, ICE

 

Its a temp controlled system. No need to drive it, it will heat up just fine sitting in place. Raise the rpms with foot on throttle if you want to get there quicker than letting it idle....

 

Some

more info

 

Thanks BigPhil, you are right that N14 wiring does not fit mine
Thanks flightops, yes, without o-scope there will be no proper further diagnosis on this
l
It would be interesting for me to learn what the key word "Activation" in the description of the fault code 2EE5 means actually. The error does not light up the MIL.

As far as I think I understood, the MAP Thermostat is basically a standard wax/spring thermostat with opening temp of 105°C. The MAP function is, that if the DME sees the temp is already near to 105°C, and it can be seen that heavy load is requested, then the hater element melts the wax although the temp at the element is still below 105°C. Therefore, the risk that inside the channels in block and head the coolant is going to like 120°C before the wax element opens is reduced.

To check If this system still works, I should speed around with scope in the car and wires in parallel to the plugs. Or If I want to do it in my garage, I would need to cheat the temp reading.

Would you also think like that ?
|
Best rlegards,
ICE

 

Heater is PWM powered ....

 

Thats what B49, “ecm switched earth” means in the chart that mike posted. Mike tends to know what he’s doing with respect to these cars…

ECM (DME) pulls to ground to control the circuit, like most ecm controlled circuits do.

I measure that sort of thing with a multimeter and a ’scope to confirm proper operation when chasing down a fault. multimeter to confirm system supply voltage, scope to confirm ecm control signal.

 

Wiring schematic

 

This wiring diagram is the wrong one for your engine - yours is N12, that diagram is N14 turbo engine