2008 RS Starting Problem

greg99

New member
Heads up for Roadtrek RS owners. I recently purchased a 2008 RS Adventurous from American RV in Grand Rapids MI. On the day of pickup, after I took it for a test drive it wouldn’t start. It was towed to the local Sprinter dealer (Hoekstra Specialty) and they found a loose connection between the ECU and TCU and could not reproduce the problem after reseating the connector at the TCU. I had driven it for about a month and 1500 miles with no issues and then had the same problem occur again. The Hoekstra facility in Troy MI had it towed in and found the same problem with the connection at the TCU. Their assessment is that the installation of the coach wiring/inverter under the drivers seat by Roadtrek resulted in stress on the wiring bundle at the TCU which resulted in the problem. They relocated the TCU to relieve the stress. While not an issue in this case, they also decided to move the ECU (under the hood) from where Roadtrek had relocated it when installing the second coach battery (down low where it is exposed to road spray) to a location higher up that is not exposed to road spray.

In my case, a key indicator of the source of the problem was the lack of a gearshift position indication on the dash display, indicating that the gearshift position was not being received from the TCU. This prevented engine start, the starter is not engaged. Just a heads up if you see this happen on your unit.

Kudos to American RV and Hoekstra, both have been great to work with and they have both provided great service to get the problem resolved. Hoekstra consistently gets good reviews as the place to go for Sprinter service in Michigan and I agree.

Greg McHugh
2008 RS Adventurous
 

sailquik

Well-known member
TCU= Transmission Control Unit.....what monitors and shifts all the functions in the NAG1 transmission.
ECU= Engine Control Unit (Module)...the main engine mangement computer that reads all the sensors and modifies the boost/fuel flow/and all the other engine management functions.
It responds to the Throttle Position sensor/module as far as sensing how much power is being
asked for and modifies all the "adjustables" to meet the power demand while keeping the emissions low.
Roger
 

Altered Sprinter

Happy Little Vegemite
This may be reverential to the above,not sure.

Mercedes ran into issues on the NCV aftermarket conversions with bundling wiring as it previously cut out interference with some hertz ratings Euro reference.

What happened as a result of bundling hot spots were being created with voltage fluctuations which resulted in false signals being sent to the ECU hence the above,,of which under certain conditions the units were mysteriously catching on fire.

As aftermarket wiring re-installations, versus Mercedes OEM wiring set alarm bells off Mercedes worked with the aftermarket up-lifters, 'no liabilty on Mercedes either'.
Solution was earthing off at certain body points with out looped or twisted bundling and in doing so by incorporating load resistors, to prevent sporadic warning messages to appear on the dash units or ECU storing false codes, that in effect resulted in LHM or fire damage etc.
I posted pictures on an older thread a long time back, but not sure if this is what went wrong in the UK,as to the above post , but sort of rings a bell.
Richard
 

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