AMC Tech Case – Rat Race
This Mercedes E350 came in with a no start condition, radio inoperative, and a host of other electrical issues. We weren’t the first to work on this vehicle, it was clear that many hands had been in here before, and apparently given up without success.
The highly skilled AMC Service Techs Kyle and Scotty collaborated, were able to trace the fault, after a good day of diagnostics, and interior disassembly, to a electrical wiring and fiber optic cable issue, located inside one of the wire chases. As these chases run from the front to the back of the vehicle, much of the interior had to come apart to follow and find this issue.
Seems the friendly rodents had been at work in a big way. Wires for the CAN Data bus were chewed and shorted, and the fiber optic cable apparently served as one rodent’s tasty snack. The general diagnostic outline, start with signs and symptoms. Then by carrying out a systems report on the Mercedes XNTRY diagnostic computer, identifying affected systems, which lets you know the CAN bus is down. Using a digital oscilloscope to look at the actual data bus signals is the follow up to this.
The hard work is measuring data bus resistance, individually removing each item from the BUS, then measuring resistance on the wiring harness of each item until the fault is identified, to confirm if it is a wiring or module fault, hence the wholesale interior removal. And you can’t stop at just one fault, as there may be more than one problem on the data bus devices.
Kyle has a solid service background, but this was his first big job doing high level diagnostics on a late model Mercedes Benz, and using the spiffy Mercedes XNTRY diagnostic computer. I am very proud how Scotty and Kyle worked as a team to diagnose, isolate, and ultimately correct this service challenge.
Teamwork is what we are all about here at AMC, you don’t get just one of us, you get over dozen folks working together to make it happen for you, and your car.
Earning your trust, every time you turn the car…that’s what we do…every day…for the last 30 years. Click here see what our happy customers have to say about us and our service at AMC Customer Reviews.
If you have questions, or if we can be of further assistance, just call us at (207) 882-969, we’d love to meet you, and your car!
Bruce and the AMC Service Team