Anyone have experience with ABS code 48?

'98 SR5, v-6 auto, 4WD with ABS. 172K on the clock. About 2 weeks ago I started to get an intermittent ABS light. First only on the freeways, now will happen randomly on just about any road/speed. Many times by the time I got home the warning had self-canceled, but I did manage to pull a code 48 (open or short in rear diff lock circuit). Just to fill in the blank here, for those w/ABS when you lock the rear diff the ABS auto-disables. I have the shop manuals, and followed the troubleshooting guide. It states to first check relay box 1 (the big fuse/relay box in the engine bay). All fuses/relays OK, and I've never done (modded/added) anything there. Next is JB1 (the fuse box on the drivers side behind the dash), all is OK there, the gauge fuse specifically is OK as are all the others. Next is JB3, up and behind the instrument panel, about 6 plugs and 4 gazillion wires go there, and all plugs appear snug and tight. Next is 'another' JB3 which from the shop manual drawing looks to be behind the center stack air vents...not sure how difficult to get behind there so I've passed checking it for the time being. Haven't been able to test the ABS yet (dry roads, no dirt roads nearby, etc), but I did test the rear diff lock today and it seems to function as before (i.e. needed to drive forward a bit, gentle turn on the wheel to get it to engage, got the dash light to stop flashing, and got it disconnected OK...).

So seeking any advice anyone may have that might help solve the problem before I take it to the dealer and have them likely start throwing parts at it until they can solve it.

W/in the past year-ish I did do the Tundra front brake upgrade, and it all went well until I snapped a caliper bolt (dumb on my part), and ended up messing up an ABS sensor fixing it, but a new sensor solved that issue, and never any other ABS-related issues until this one camp up, so makes me believe they're not related.

AND...for those who would 'helpfully' suggest I either 1. ignore it or 2. pull the fuse...don't even bother. ABS was one of my 'must haves' when I purchased the truck. I consider it a critical safety feature on a p/u truck w/a relatively light rear end. I wanted it, I got it, I paid for it, I want it to work. End of that part of the story.

Thanks!

 

My ABS light is on all the time since I hung my calipers up by something not strong enough the 1st time I did my brakes 3 years ago. And when the caliper fell it yanked on the sensor and now the light won't go off. How do you replace the sensor? Did you do it yourself? I see where it's at. Then this last weekend I did the tundra upgrade and locked my new brakes up going 65 mph and the anti lock brake system worked just fine. I would like to get the light to go off though.

 

I had both of your symptoms - I had to replace my right front ABS cable from the lower shock tower ABS sensor connector all the way into the engine bay. I picked it up on eBay. The wire got small cracks in it over time from movement/rain/salt. There were three cracks in it total and were making the wiring brittle and cracked. Hard to see, but you could tell they were there if you flexed the cable and looked really closely at it. Run your fingers over the entire length and feel for cracks in the insulation/covering. My symptoms were the familiar "ABS braking" noise from only the right front when I went over speed bumps in my neighborhood. Since I was always going so slow, the braking was minimal. Once the cable went in, my ABS light went off and stayed off. You may want to get your cable from Toyota. I know it is more expensive, but the cable I got was about 2" too short to follow the original path to the engine bay. It has been working for a year now with no issues even if it was not a perfect fit. I suspect the left one will need to replaced at some time in the future. Good luck.