Hey, (long time reader, first time poster)

My main problem is I am losing communication with SLABS after traveling over 10 MPH and the 4 amigos come on, but I'll start from the beginning:

When i'm key on/engine off > I get code 0604 Front right sensor output too low. Only the ABS light is on at this point. When I turn engine on, still only the ABS light is on. After traveling over 10 MPH, I hear a chime and the 4 Amigos come on: ABS, TC, HDC, and BRAKE. At this point my scanner loses all communication with SLABS. After I shut the engine off and go key on again, i'm back to where I started. I can clear the code at this point and the ABS light goes off, but all 4 amigos always come back on after traveling over 10 MPH. Why am I losing communication with SLABS?

I have recently replaced the shuttle valve switch, did option B wiring, and replaced both front wheel speed sensors.

Any input will help.

Thanks,

 

 

hub sensor shouldn't affect communication with slabs. i've replaced a couple of hubs because of bad sensors and they didn't throw all those lights.
have you tried pulling the slabs unit and cleaning all of the connections going to it?

 

I do not know why you say it loses communication.
Communication with what ?
The chimes and amigos show after a few MPH as you experience, the ABS alone shows before the amigos at start/idle/crawling speed.
I see that daily because I run 2WD only, locked transfer case, no front driveshaft for at least 7 years.

 

I pulled SLABS out today. Opened it up and the board, solders, pins all look perfect. The connectors and connections also look solid. Grounds look good for SLABS and ECU.

What confuses me is I am able to read and clear codes in key on/igition off, but lose communication and am unable to read codes once I drive faster than 10 mph.

 

What kind of scanner are you using? Make and model? Anything less than Autologic, Testbook, or a Shop level SnapOn or other might get kicked out above 10mph because the car doesnt want you messing with ABS functions while driving.


Replace the sensor/hub, clear fault, test drive

 

What scan tool is telling you "lost communication" with SLABS unit? Whenever the ABS SLABS Unit has been cleared of any faults the ABS Light will illuminate upon startup and once it see's activity from all 4 Wheel Sensors the light will go out. It sounds to me the SLABS Unit is communicating properly as it's illuminating the ABS light upon startup, then when you move instead of the ABS light going out when it see's the proper activity it instead faults and trips the ABS, BRAKE, TC, and HDC warning lights.

If your scan tool is LR specific you should be able to verify the wheel sensor activity. I'd start by verifying the wheel sensors, and going from there. I've also seen some scan tools attempt to reset faults, but they never do, so whenever you drive the D2 the faults come right back even after things were repaired/replaced.

 

I'm using an Autel MaxiLink ML629. My master tech friend also used a Snap On Solus and had the same issue.

I think I'll take the consensus advice and just replace the right front hub/sensor assembly, clear codes, and go from there.

I'll be praying to the car God's a lot on this...

THANKS!

 

With my iCarsoft LR2 or my Nanocom I watch the actual wheel sensor output. Usually the results are instant on guessing which one is acting up. If you can view the wheel sensor output you can verify the sensor. Of coarse the plug to the sensor has to be in good shape. If it's cracked and brittle you can just use some butt connectors that have heatshrink on them and it'll be fine.

 

I had the same issue many months ago using a Delphi knock off scanner. Communication with SLABS drops at 10mph. My scanner reported a bad right rear sensor. I replaced it, and several days later, the lights came back. Replaced it with a different brand, and same issue.

Finally viewed the live data on my scanner for sensor voltage as I drove in an empty lot at 5mph. Live data showed it was the left front sensor that had fluctuating voltage. Replaced the left front sensor and have been trouble free since.

Live data is your friend!