ABS Light Question

Truck in question is a 2003 Xtra Cab 4WD V6 5spd

Friday I installed Icon UCAs and Coilovers. I disconnected the ABS sensors up front to make room to work in there. Also replaced front and rear brake lines with stainless braided lines (extended line in the rear). Noticed the Orings on the ABS speed sensors were in bad shape.

Upon reassembly of the front end, I simply reinstalled the ABS sensors with the bad o-rings. On the test drive (checking out the new shocks), the "Brake" light in the dash was flashing once every 30 seconds or so. Brake fluid level was good, and brakes were working well.

Next day, I pulled the ABS sensors and installed new O-rings from an assorted O-ring kit (non-OEM knockoff), and then reinstalled the sensors. These newer Orings appear thicker, to the point that the sensor doesn't seem to seat fully. Now I have a solid ABS light on the dash at all times, but no more flashing of the brake light on the dash.

Called the local parts counter and got the OEM O-rings (96723-19021) ordered, and they'll be in tomorrow. I'm assuming the ABS light is due to the improperly seated sensors. Is there anything else I should check or rule out, or am I likely assuming correctly that it's the sensors not being seated properly?

Haven't ran the scan tool to check for ABS codes, but perhaps I should do that next?

 

Check the condition of the wires! you may have pulled one of the wires out of the connector by mistake or the wire is frayed or broken not making a solid connection.

When I was looking into my abs issue i found a video that showed the blinking sequence will tell you what sensor is having the issue. I hope this helps a little.

 

Sounds good, and will do. The truck is at the allignment shop (needs an allignment after the shocks and UCAs went on). Once I get it back I'll inspect both sensors and wires and report back.

 

So I managed to get the light to go off. I did two separate things, so not sure which cleared the light.

First I pulled both front sensors once more, wiped them clean and tried resetting them with the OEM O-rings. Unfortunately the Orings I got from Toyota were clearly too large of a diameter. So I put the aftermarket thicker O-rings back on. I was able to work the O-rings farther up the sensor, beyond the groove they like to sit in, and this allowed the sensors to seat more fully into the knuckle.

Then I hooked up the scan tool. No codes thrown, oddly. Still clicked "clear ABS DTC codes". Then disconnected scan tool and took a 10 minute test drive with no ABS or flashing "Brake" light on the dash.

Hoping I've actually solved the issue.

 

Bump

Ok so I've got a new braking issue that I can't help but feel is ABS related.

When I begin to brake (to come to a stop), the brakes feel normal for the first ~70% of the braking process, then when the vehicle reaches like 3-5 mph, the brakes seem to let go (brake pedal gets soft and goes to the floor (or close to it), then it suddenly regains its pressure after a couple seconds of the "oh shit" feeling. Then it brakes really hard. This is all one consistent pedal application (not pumping the brakes).

My ABS light isn't on, but I can't help but feel like this is related to the wheel speed sensor dilemma I was having earlier in this week (see above posts for details on that) interestingly the brakes were working perfectly with the ABS light on, and this new issue arose once I got the light to go off.

I did try bleeding the brakes and got minimal air bubbles out. The brake pedal feel is really good at first, so I don't believe this is a simple inadequate bleeding issue. Also in all the brake work I've done to the truck over the past week, I've not let the fluid in the reservoir drop below the minimum line. Could me having swapped out the front and rear brake lines allowed air from below into the master cylinder, or abs pump perhaps? Can a bidirectional scan tool actuate the ABS pump in a first gen Tacoma to get the air out of the ABS pump if that's the case?

 

Figured it out:

Went to O'Reilly's and bought two assorted box of oil filter O-rings. Scrounged 1 O-ring out of each box that was the perfect size, used QD electrical connector cleaner on the tip of the speed sensors, reseated them with the new O-rings, and all is well again with my brakes.

 

That is a crazy issue (low speed/B pedal drops)
Way Glad you figured out

those teeth in ABS ring just weren’t reading sensor magnet?
Once you added that oring the sensor position was to spec?

 

My money is on the pedal getting soft again in your near future. I don't think it has anything to do with the ABS, as that system either works or throws a light and doesn't work. My money is on a failing booster (unless you have recently replaced that) or master cylinder. How did you bleed the brakes after your recent work?

 

Hmmmm^^^

 

I'm guessing yes and yes. Maybe there was a spec of dust (or more likely metal flake) in the tip of the sensor?

Apparently the ABS system and those wheel speed sensors are highly sensitive to their positioning relative to the abs ring in the hub. I'm just glad I got it fixed because now I can go romp the truck with my new fancy suspension without worrying I can't stop lol

 

Grabbed the wife and had her pump the pedal while I went around all 4 corners (typical RR, RL, FR, FL pattern).

Hoping you're wrong, but that fear is in the back of my mind. Just strange that it all coincides with me doing the front suspension work and removing those ABS sensors (and the original Orings falling apart in the process).

 

Also isn't it strange that with the wrong O-rings it created the weird braking sensation every brake application and then after the correct O-rings were out on it didn't do it at all on a 60 mile shakedown drive? Maybe I'm just being optimistic because I don't want to deal with the master cylinder or booster though

 

I think the o-rings and abs stuff is just a red herring.

You probably haven't pushed the brake pedal during normal use as much as you did to bleed the brakes the old school way... The boosters and MC's don't last forever.

I can't recommend the Motiv power bleeder kit w/ a 3rd party adaptor enough. It's so much better. My friends who wrench borrow it all the time to bleed their brakes for flushes, etc.. all blown away by the pedal feel afterwards.

 

I have a motiv bleeder, just never could figure out how to use it right. I wonder if it's because I don't have the right adapter (or any adapter at all). It's been sitting in a cabinet in the garage since I tried using it once and made an absolute mess everywhere. Does Amazon carry the adapter?

 

oh man, yeah,

$37 SMOTIVEPRO 43mm Master Cylinder Bleeder Adapter Compatible with Toyota and Lexus

Amazon.com: SMOTIVEPRO 43mm Master Cylinder Bleeder Adapter Compatible with Toyota and Lexus : Automotive

Makes a HUGE difference. They just shouldn't sell the unit with the universal adapter. I make it work by using a hole saw that was the same size as the MC lip, and cut a grove into it, but it was still touch and go. The adapter makes it so much better. Just make sure you have some stuff on hand to connect it to the tube on the motiv. I think I had to run out and get something for that, but I don't remember if it was just a hope clamp or a threaded brass fitting...

 

Thank you I will definitely give this a whirl

 

Red03
I didn’t buy that b-ass one^^^^but some cheap Amazon hand held trigger pump one
Took me 3 separate uses(freakin $30 of b fluid)to figure out how to use
Trick I finally learned, was to pump the trigger till pressure gauge read 30…..THEN release the caliper bleeder screw
Sorry if this is known to u and others
But once I figured process out was easy peasy….no bubbles all 4 corners

BTW
Did u bleed LSPV as well?
Or have a delete?

 

I didn't bleed the LSPV nor did I delete it, but perhaps I should. I think have the same hand held pump as you also (have that and the Motiv tool). I've not used the handheld to bleed but did use it to pull old fluid out of each corner and pull clean new fluid through

 

yep there is a bleed screw on LSPV (oldsilver pointed out to me after my 1st failed attmpt to bleed taco's b system)

 

Interesting. I've got the Motiv adapter on order, so once that arrives I will rebleed the system, to include the LSPV, for good measure