Motive ELD causing ECM fault code.

1995 Pete 379 with Detroit S60 12.7 - with Opti-idle (post factory installation presumed). Peterbilt wiring diagram SK25038 for ECM reference.

Motive (formerly keep trucking) ELD device, connected with jumper harness from cab side data/diagnostic port - port also serves a Scan Gauge - 4 sensor display (oil/temp/road speed/assumed MPG etc).

The check engine light began lighting and staying lit, issue and frequency increased over time. This would disconnect the Scan Gauge. Plugged into a laptop which also had issues with connecting (Data Link error).

Puzzling and annoying.

Pulled ECM vehicle side connector, and on a hunch, tested the connectivity between the 30 pin ECM plug and the cab side J-port, specifically C1 and C2 on the ECM plug (J1587 datalink) and the J1587 +/- on the cab side J-port - which only has 4 wire input - 12V+/-, and datalink +/- .

With the Motive ELD plugged in, there was connectivity between (+) on the J port, and (+/-) on the ECM plug.

Disconnect (tried both solely the jumper, AND the cable connection into the Motive ELD black box) - and the connectivity reverted to (+) at ECM and J port, and (-) at ECM and J port.

Basically - if I'm understanding correctly, the Motive ELD black box is/was creating a short or interference between the 2 J1587 signal wires, feeding back into the ECM, and creating the fault code.

Having unplugged the main jumper port to the ELD, it removed power, and after a while I'm guessing it performed some form of power reset or reboot.

I test drove it not knowing whether or not I had solved the problem or not - and called Motive, who suggested reboot/power cycle the black box, and advised the Motive app update, and up to date interface (I'm using an old iPhone that is no longer supported for software updates) - and sent me a list of 'more compatible (newer) devices/OS etc.

Diagnostic toggle switch on the dash now shows SEL - Code 25 (No active codes), and CEL 56 (J1587 data link fault). I'll run it to the mechanic and plug in the laptop to clear the CEL inactive code, and monitor.

Wondering whether anyone else has had this issue, and documenting my findings in case it helps others.

TLDR? - ELD's blow goats, and technology is making us dumber, and life more difficult, whilst providing a massive revenue stream for companies invested into regulation in the name of safety and . . . never mind.

 

Interesting - it's not just me then.

I wish I had unplugged the Motive first before going any further, but at least I did prove the source of the fault to myself.