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Paul M ASE Master
Paul M ASE Master, ASE Master Tech
Category: Mercedes
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Experience:  ASE Master Tech 20+Years
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I am getting a message on my 99 E320 Engine Fan and showed

Resolved Question:

I am getting a message on my '99 E320 "Engine Fan" and showed a fan in the center. The message started popping up intermitenly when I would start the car when the outside temperature was hot (around 80 degrees). The temp gauge would move up and then the message would go off once the car was running. I took it to my shop and they had never heard of the message "engine fan". They kept the car to check it out, but, the day was cool so the message never came on. They said they could replace the fan for $500+and SEE if that was the problem.
Then, if that didn't fix it they would change something in the electrical system and that would cost $250+. So, it appears I may potentially pay a good amount of money and still not be sure that will fix it. I'd would appreciate your intput.
Thank you,
Barbara
Submitted: 4 years ago.
Category: Mercedes
Expert:  Paul M ASE Master replied 4 years ago.

Hello and thank you for using Just Answer

 

did they verify the fan is running? I found a reported case of the Fan Control Module n76 causing this code and also causing the fan to run constantly.

 

I am attaching this report below:

 

Vehicle Application:
2000 Mercedes-Benz E320 3.2L
Customer Concern:Cooling fan runs continuously with the key on, display in the instrument cluster shows; 'Engine fan - visit workshop'.
Tests/Procedures:1. Check all fuses. Inspect connections on the Engine Coolant Temperature (ECT) sensor and A/C pressure sensor on the receiver-drier.

2. Connect a M-B fully functional compatible scan tool and retrieve/record/clear DTC's in the Powertrain Control Module (PCM), Signal/Activation Module (SAM), Automatic Air Conditioning (AAC), and Instrument Cluster Module (ICM).

3. Attempt to access the activations menu in the scanner under the PCM. If available, use a scanner to activate the engine cooling fan and control it using the scan tool. If the fan is not controlled, check voltage signals at the Fan Control Module (FCM) (N76) located under the left front headlight behind the bumper.

4. Use a Digital Multimeter (DMM) for voltage testing at the connector on N76. Pin 3 Red/Black (RD/BK) should be battery voltage (B+) at all times. Pin 6 Black/Red (BK/RD) should be B+ with the key in the on position (#2). Pin 2 Brown (BN) should be constant ground. Pin 5 Yellow/Blue (YE/BL) should be the control signal from the PCM, depending on the control signal from the PCM the voltage will vary between 2v (low speed) and 11v (high speed) approximately. If voltage is high above 10v all the time, disconnect the connector to eliminate the possibility of feedback voltage from the N76 module and recheck command voltage on pin 5.
Potential Causes:A/C Pressure Sensor
Defective Coolant Sensor
Defective Fan Control Module N76 - Faulty fan control module N76.
Trouble Code - Stored DTC.
Tech Tips:A fully functional Mercedes-Benz compatible scanner is required to be able to clear DTC's in the control modules and eliminate default activation of the fan.
Diagnostic Codes:None

 

let me know if you need more information

 

thanks

 

Paul

Customer: replied 4 years ago.


The message ONLY comes on when the outside temp is around 80 and the car has been sitting in the sun. Then after the car runs it will go off and then click on again later. It is not a constant "engine fan" message when the key is turned on.

Expert:  Paul M ASE Master replied 4 years ago.

in this case it is quite possible the engine fan is setting the code.

 

where they able to test the operation of the fan?

 

sounds like everytime it gets warm enough and the fan wants to run is when you are getting the message

 

did they verify the fan is running or not? also did they verify it is getting the power signal?

 

they should not need to guess whether it is the fan or the control... either the fan does not operate (they can power the fan directly to test this)

 

or it is not receiving the power signal to come on.

 

ask your mechanic if the fan runs? and if not did they try powering it? also did they check for voltage signal to the fan when warm?

 

it is most likely going to be the FAN MOTOR itself.... or the FAN CONTROL MODULE

 

they need to perform the tests I mentioned

 

click here to view the wiring schematic of your fan circuit

 

let me know what they tell you

 

thanks

 

Paul

Customer: replied 4 years ago.

Your answer souunds logical to me! Now, how do I get back to you without having to pay again? Also, can you approximate cost of repairs for either of the the fan or the control module? I see you are from Newington so your estimate should be close.

Thanks.

Expert:  Paul M ASE Master replied 4 years ago.

We can continue communication through this thread. you receive a message to your email any time I respond to your questions and there is a link there to bring you back into the question.

 

I do not have any pricing on the parts

 

but labor on the fan should be around 1.5 hours

 

and for the Fan Control Module labor would be less than 1 hour

 

just curious where does it tell you I am from newington?

 

Paul

Customer: replied 4 years ago.

Your profile. Actually if you have 20 years experience you may now be living outside CT. Your profile lists your education with Newington being the first and having a CT license.

Expert:  Paul M ASE Master replied 4 years ago.

Oh ok... I just never had any one mention it before so was wondering.

 

anyway yea you should just verify the FAN MOTOR does run when power is jumped to it. and then you know the motor is good and the problem is most likely in the FAN CONTROL MODULE

 

remember to click accept so I get credit for my answer

 

Positive feedback is greatly appreciated

 

thanks

 

Paul

Paul M ASE Master, ASE Master Tech
Category: Mercedes
Satisfied Customers: 4681
Experience: ASE Master Tech 20+Years
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