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So I recently posted about tackling my three amigos, below are the faults I had.
ABS Codes.
This past weekend I did "Option B" bypassing the shuttle valve and replaced both front wheel speed sensors. Still had the lights on after that so I went to my local Midas and had them reset the codes today but they came right back as soon as I started it up. They seem to think the SLABS unit is starting to fail because the SRS light is also on but shows no faults. Should I look into replacing the SLABS unit? I figured by bypassing the shuttle valve it would at least eliminate that code.
Did you replace or meter out the shuttle valve switches? You don't bypass the shuttle valve switches with Option B, you bypass the weak internal connection that is a known weak spot that fails. Whenever I perform an Option B I always replace the shuttle valve switches. Sure they "could" be fine, but they're nearly 20 years old and only cost 50.00 and I'd rather do the job once and be done with it for nearly another 20 years.
You have to make sure you choose a good ground for the Option B as well or it will not work. The bolt that holds the AC line down works, but it needs to be metered and tested.
Did you replace or meter out the shuttle valve switches? You don't bypass the shuttle valve switches with Option B, you bypass the weak internal connection that is a known weak spot that fails. Whenever I perform an Option B I always replace the shuttle valve switches. Sure they "could" be fine, but they're nearly 20 years old and only cost 50.00 and I'd rather do the job once and be done with it for nearly another 20 years.
You have to make sure you choose a good ground for the Option B as well or it will not work. The bolt that holds the AC line down works, but it needs to be metered and tested.
I metered out both switches and both responded correctly 3ohms open 2ohms individually closed and 1ohm both closed. It looked to me as if the previous owner had already replaced the whole shuttle valve assembly because it was clean as a whistle inside (that or its been sealed very well and never opened since it left the factory).
I used that same bolt and like you said, checked the ground when finished and it was fine. I was very careful to sand down around the bolt to remove some paint for a good ground connection.
So im kinda at a loss for why I would still be getting a code for that even after Option B. Im going to a LR rally here in Florida this weekend and I spoke with someone who said he's brining his Hawkeye so I can get a better reading on the codes. Unfortunately I was hoping I could knock this out before the rally so I could have some fun on some of the trails.
Check the wheel sensor connectors in the engine bay for front left and right and clean them up. You can do a ohm test to for acceptable values per RAVE
Check the wheel sensor connectors in the engine bay for front left and right and clean them up. You can do a ohm test to for acceptable values per RAVE
when I hooked up the new ones I sprayed the connections with electrical cleaner and used a cotton swab to get any dirt out. I ohmed out the new abs sensors before I installed, I want to say they ohmed out at 1ohm. I read up on another forum that there’s a way to rotate the wheel and test the voltage on the sensor side of the connector to make sure they are working but I haven’t had time to do that yet.
when I hooked up the new ones I sprayed the connections with electrical cleaner and used a cotton swab to get any dirt out. I ohmed out the new abs sensors before I installed, I want to say they ohmed out at 1ohm. I read up on another forum that there’s a way to rotate the wheel and test the voltage on the sensor side of the connector to make sure they are working but I haven’t had time to do that yet.
Try to disconnect the plug from the slabs and test each sensor ohm reading from there. All 4 should be close to the same and would tell you if one has bad wiring or connection
Try to disconnect the plug from the slabs and test each sensor ohm reading from there. All 4 should be close to the same and would tell you if one has bad wiring or connection
Ill give that a try this weekend and see what I come up with, Ill also have access to a nanocom this weekend so hopefully that will pinpoint exactly what im looking for. Ill follow up after the rally this weekend with the results. Thanks!
The front wheel sensor cables often crack/fracture and fail due to continuous steering movement which gives an 'intermittent' 3 Amigos reading on the diag tool. It's best to replace the sensors and cables back to the plug and socket. Doing Option B in isolation I have found sometimes isn't enough without replacing the modulator shuttle valve seals which often leak out some of the brake fluid causing electrical faults.
04-23-2018, 05:56 PM
SLABS (ABS) Faults.
