shimmy

Hey everyone,

First post here. I'm new to Mercedes, but not new to turning wrenches. I come from the BMW world, so I'm used to having a bit more info at my fingertips. Long story short, my wife's '15 GL550 lit up like a Christmas Tree with ABS/Traction Control Inoperative/"Pre-Safe Functions Limited" warnings on Friday. Pulled codes, which indicated an issue with the left front speed sensor, so I installed a new one, but no luck. I traced the wires back from the plug and found a break in both wires leading back to the main harness.

I know splicing them will likely not resolve the issue, so looking for a part number for the harness which the speed sensor plugs into. I've tried finding it on Nemiga Parts, but the drawings/descriptions are pretty generic. Any help would be greatly appreciated.

-Shimmy

rapidoxidation

I'm curious why you suppose that repairing the wires wouldn't fix the issue?
Of course you'll also be looking into what compromised them in the first place, yes?
I'd start with fixing the wires and reinforcing (extra sheathing?) if needed to protect them.

As a new Mercedes shadetree, you'll want a copy of WIS/EPC (the Mercedes repair manual and parts catalog). Ebay has it all day long for about $20. It's a pretty steep learning curve but you'll find your part number there.

shimmy

Thanks for the response and information re: WIS/EPC.

I'll be attempting to repair the wires with splice connectors which include solder, however knowing how finicky European cars can be when it comes to sensor values, I'm not terribly optimistic that the splice connectors will resolve the issue. If they do, that's great, but given that this is our family hauler I'd rather install a new section of harness anyway.

Have already been wondering how it happened. The wires broke near a zip tie that mounts to the inner side of the fender directly below the coolant reservoir in an area that presumably doesn't see much movement. Can't tell if it was pinched during a previous repair and finally broke, or if the zip tie from the factory just finally wore through the Tessa tape/sheathing/wires.

shimmy

Update: Got the wires spliced this morning, and vehicle back on the ground. Took it for a quick spin. Warning lights on dash have all gone away, but my generic code reader is still showing C0031 and P061A after erasing codes. Have been advised by a different group that those should go away in a few hundred miles, presumably as the computer acclimates to the new readings. Will report back.

shimmy

Update: Been about a month, and a few hundred miles. I've been pleasantly surprised that there haven't been any issues with the ABS Sensor since. Thanks for the advice, everyone.

rapidoxidation

I love it when fixes get updates. Thanks for coming back!