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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8330
Experience:  I am ASE Master Truck Certified.
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On a 1995 freigtliner with a3406E engine the engine has

Customer Question

on a 1995 freigtliner with a3406E engine the engine has begun to derate I believe the problem is possibly in the coolant level sending unit it has a 4 wire connection is there a way of testing sending unit or wiring harness to see if this is the cause?
Submitted: 2 months ago.
Category: Medium and Heavy Trucks
Expert:  Cat Man replied 2 months ago.
Thanks for asking your question. I will try and help you out.
Does the red or yellow check engine light come on while drivng?
Customer: replied 2 months ago.
the red shut down light comes begins to flash and engine will derate while driving or shut down completely .
Expert:  Cat Man replied 2 months ago.
Since the light is coming on. I would like to pull the flash codes by using the cruise control switches. If you have never done this. Here is how.Use the following procedure to retrieve the flash codes from the check engine light:
Turn the ignition key switch to the On position/ Engine OFF.
Turn the cruise control ON/OFF switch to the OFF position.
Move the SET/RESUME switch to either position. Hold that position until the yellow lamp begins to flash.
The yellow lamp will flash in order to indicate a two digit flash code and the SET/RESUME switch may be released. The sequence of flashes represents the system diagnostic message. Count the first sequence of flashes in order to determine the first digit of the flash code. After a two second pause, the second sequence of flashes will identify the second digit of the flash code.
Any additional flash codes will follow after a pause. These codes will be displayed in the same manner. Flash Code 55 indicates that No Detected Faults have occurred since the ignition key switch has been turned to the ON position.Let me know what two digit code you get and I can tell you what the problem is.
Customer: replied 2 months ago.
I have attempted to retrieve flash codes and there is a problem there as well nothing works on the cruise
Expert:  Cat Man replied 2 months ago.
I see. Thanks for the information.
It's possible the low level sensor is your problem. However it could be many other things.
It's best to have the ECM read and checked for codes. It's the best way to verify since the cruise procedure does not work. I am sorry. I wish there was another way.Please reply back if you need more help or have more questions. I am happy to assist.
Expert:  Cat Man replied 2 months ago.
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.

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