[hcip]

I have problem in BMW 3series with cooling fan not running
I scan with PASoft and it appear the code 279D cooling Fan error

this bmw was diagnosed before by BMW service personnel and they told that the ECU/DME is faulty

I have a used DME with exactly the same number and I try to installed it,
but the car didnt run the engine , I swap the EEPROM ST95080.

what file do I need to transfer in donor DME to run the engine?
is there any possibilities that the DME was really faulty when the only problem is cooling fan?
there is no any indicator light glow in the cluster even the Check engine indicator

Thanks in Advance for any one who can help me

[CATAHA]

I have problem in BMW 3series with cooling fan not running
I scan with PASoft and it appear the code 279D cooling Fan error

this bmw was diagnosed before by BMW service personnel and they told that the ECU/DME is faulty

I have a used DME with exactly the same number and I try to installed it,
but the car didnt run the engine , I swap the EEPROM ST95080.

what file do I need to transfer in donor DME to run the engine?
is there any possibilities that the DME was really faulty when the only problem is cooling fan?
there is no any indicator light glow in the cluster even the Check engine indicator

Thanks in Advance for any one who can help me

AUX Fan problems as follows
Temp Sensor (lower rad hose, Cylinder Head)
Temp Wiring
Fan Fuse
Fan Fuse(PWM) on fan
Fan Wiring
Fan
Fan Relay
A/C
IHKA Controler
DME
So..... Which one of those have you tested?
Have you tested them all?

Also very important factor Volt meter is your TRUE tool
When having right tools and when not having right tool for the job
BMW Scanner 1.4
W I L L---N O T---G O I N G---T O---H E L P---Y O U---T O---F I X---T H I S---P R O B L E M

and too eliminate future Q/A
look on this forum
Rheingold / INPA
TIS
WDS
Mitchell On Demand
AllData

[hcip]

Never checked yet the coolant Temperature sensor and engine temperature sensor,
the cooling fan has already change with a new one, the AC compressor works when the aircon switch is on in climate control. only the cooling fan doesnt works and the temperature gauge in cluster was indicated an overheat

I have no other tools for BMW except the GT1.

Thanks

[CATAHA]

Never checked yet the coolant Temperature sensor and engine temperature sensor,
the cooling fan has already change with a new one, the AC compressor works when the aircon switch is on in climate control. only the cooling fan doesnt works and the temperature gauge in cluster was indicated an overheat

I have no other tools for BMW except the GT1.

Thanks

May be that's your problem
"temperature gauge in cluster was indicated an overheat"
Temp Sensor or Wiring

GT1 Will work too, to show and activate things
Not that long ago.... i had to look at the car (X5) fan would work ALL the time.. and not communication to battery etc..... it end up been power cable

[hcip]

May be that's your problem
"temperature gauge in cluster was indicated an overheat"

I mean the temperature indicator has up to overheat when the engine run a few minutes, but it goes to zero when engine is cold

I will check on Monday the coolant temperature in a lower radiator hose.....
will keep you update on monday night

Thanks

---

another question
What do you think if I swap the 28F800 flash IC from the original DME to the Donor DME?
do you think the engine will run by the donor ECU?

see the attached picture

[Node]

Somehow I would say you think too difficult here. Following KISS principle and taking into account information from WDS, namely:
"The electric fan is activated by means of a power output stage directly on the fan motor. The motor control unit activates this power output stage by means of a square-wave signal with duty factors (variable pulse width) between 10 and 90 % thus controlling the various speeds of the electric fan. Pulse duty factors less than 5 % and greater than 95 % do not trigger activation but rather they are used for fault detection purposes. The power output stage features its own positive and ground supply."

and following some basic logic I would say the course of action here is very simple. There should be a function in diagnostics to active the fan via activation of DME unit outputs. If you can activate it, then problem is elsewhere and may well be temperature sensor. But I can't see how BMW service personnel can be that stupid and not check that.

So lets assume it does not activate. Then there can be a fault in the fan, wire between DME and fan and DME output. Now ask yourself how DME can know if there is a problem with a fan? The wire is only output so I can only see one possibility: DME is not able to output square-wave signal onto it. Voltmeter now becomes very handy, though even simplest oscilloscope would be much better.

Disconnect control wire from the fan and measure if there is any voltage on the control wire at the fan. Measure it in both DC and AC modes (measure in AC mode after setting 50% fan speed with diagnostic program). In DC mode you will see if there is any voltage, in AC mode you will see whether there is square-wave signal. If your voltmeter is a better one and capable of measuring RMS, you should see AC voltage change as you change fan speed and that means duty factor on the wire with diagnostic equipment.

If you see zero volts in AC, that means there is no square-wave signal on the wire. Then check what you in DC. If zero, its either DME, short to ground or broken wire. If you see something like 12V in DC, its either DME again or short to some voltage. If you see some other voltage it may strange short to some other wire.

So then check the same directly at DME output and preferably after disconnecting that wire from DME. If its the same, then DME is clearly faulty. If not, then wire.

All this takes not more than 15 minutes and gives you final answer. I would assume it was done by BMW service guys and they saw that DME is at fault. Only basic logic is required to determine it.

Regarding inability to start the car after replacing DME, its due to ISN mismatch. I don't know where its stored and don't remember if it can be aligned using diagnostic equipment but I think it should be possible via service functions. However even you can't start the car you should still be able to activate the fan using output testing via diagnosis. Thats the second way to ensure the problem is within DME.

[bmwcare]

This is not a DDE/DME fault (99.9999%)

Test wiring and fan.
If DDE faulty and fan is good then usually fan runs at 100% speed.


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[Node]

He said he already changed the fan, but the new one could be faulty as well...

[bmwcare]

He said he already changed the fan, but the new one could be faulty as well...

The basic method of testing is:
Check wiring and fan...
Basic multimeter tests first on supplies/grounds


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[hcip]

Thanks Node, I will check it tomorrow