DTNA Solutions  Service Solutions  Freightliner

 SS 3125-FTL XMC 20amp and 5amp High Side Drivers (...

SS 3125-FTL XMC 20amp and 5amp High Side Drivers
(Digital Output) Load Sensing 
NOTE: There is now XMC software that will correct for the body builder optional LED lights being
illuminated dimly with key on lights off (note this option ordered through a 353-XXX data code) ,
so using a resister in parallel with the affected circuit is no longer required.

For the XMC1 (Model Year 2023 vehicles) software package 81Z-008, this is now available to the field
via Diagnostic Link update. A customer with an XMC and the 81Z-008 software package can now
connect to Diagnostic Link and they will get a message at the top of the screen about an XMC
software update being available. Updating the XMC to the newest software fixes the glowing LED
issue only.

For the XMC (Model Year 2024 vehicles) software package (81Z-010), this is now available to the field
via Diagnostic Link update. A customer with an XMC and the 81Z-010 software package can now
connect to Diagnostic Link and they will get a message at the top of the screen about an XMC
software update being available. Updating the XMC to the newest software fixes the glowing LED
issue only.

Applicable Vehicles
New Cascadia and M2 Plus vehicles with XMC Modules

Symptoms
Customer accessing 20 amp or 5 amp high side drivers (digital outputs) from the expansion module
(XMC) can experience unintended functionality (such as LEDs illuminated dimly) when the ignition is
on. Depending on how the feature is written for the output driver, customers may also experience
unintended functionality with other interlocks such as doors open (wakeup) condition.

Issue
The XMC 20 amp and 5 amp high side drivers, use load sensing on their digital outputs. Customers
installing a consumer (such as an LED) that uses very low amperage (typically less than 1 amp) can
encounter unintended functionality from the XMC output (example as stated in the symptom LED
on very dim).
This is due to the Internal diagnostic design of the XMC for load detection (dtc's) with the higher
current outputs, during an off condition.

Solution
When encountering an unintended functionality of a 20 amp or 5 amp high side drivers, as a result
of a low current consumer being used, resistance can be added to the circuits to eliminate the
sensing voltage being observed by the system. The adding of a 3W 100ohm resistor between the
power source and the ground, hooked in parallel the consumer will be enough resistance to
eliminate the unintended condition. The image below provides an example of how the resistors
would be added.
NOTE: Engineering is targeting 2024 XMC to have programing within the module that would allow
for the turning off of the load sensing feature (open loads). Currently the programming would only
apply to the new XMC modules moving forward and would not be backwards compatible

Labels :

Electrical

New Cascadia

Add tags



2 Kudos

Comment