Interesting writeup, thanks! All of PACCAR (NA and EU) swapped to the Cummins system with the 2021 emissions updates, I haven't seen anyone dive this deep into it yet! One note - in NA, PACCAR has been using heated DEF lines since the DEF lines were introduced (2010). I'm not sure if EU used them be...

Hey Ben, We teach an NVH class to our dealerships. Our warranty department has a preferred NVH tool that they pay claims for using but it's not the PS NVH. However, we use the PS NVH to help explain what the other tool is doing and the logic behind it. We have had success using the DrewLinq and the ...

thank you for the replies. i now have a better understanding of how this works. i will now try to duplicate this issue while reading data to see if i can narrow it down. Feel free to upload your recordings and/or post some screenshots if you're struggling with this one. A few of us here know J1939 ...

Hey Steve, If you haven't heard of it before, you might take a glance at SAE J2497, also called PLC4Trucks. The heavy duty trucking industry has been using PLC for communication between tractor and trailer ABS systems for quite a while. It seems to be very reliable. I didn't realize that a similar P...

It seems like this may just be a Temperature Sensor with a PWM output. I've seen datasheets for the TMP05, TMP06, MAX6666 or MAX6667. They all have similar outputs that look very close to what we have here. However I tried using their formulas to calculate temperature data from the DAF recording you...

Dominant voltages can be determined by the signal dropping close to 0V with threshold levels being different for the master and slaves. Quite why that is I’m not sure but it will allow a lot of variation in signal levels hopefully making the network more robust. As an example the master must drive ...

Hey Steve, I've seen people recommend utilizing the high-impedance probes a few times on CAN Bus signals. I'd love to see a write-up from Pico about these probes, specifically it would be nice to have something that is comparing screenshots showing the effect on the trace between a standard probe an...

I also tried the 1-wire serial decoder with it triggering on low and high. Great minds think alike I suppose! Yes, the first few pulses are unique (when compared to the rest). I concur, it's likely bus initialization. Do you have any idea what the temperature might have been when you captured this r...

Further digging into the "odd PWM" area, a few more things confirm that it's data. First of all, we see the same two messages repeating over and over. If you zoom in on that section, it will be clear what I'm referring to. The first positive pulse is always the same length (around 100 ms). I suspect...

Hi Ben, The signal prior to the PWM is indeed temperature data from the pump unit to the emissions controller. I believe it may be a communication language that is proprietary to Bosch but I'm not sure on that. When a Bosch SCR emissions system is first turned on, it enters a standby phase where it ...