Anyway around reprogramming an ABS unit

No problem.
This has me stumped.

It’s like you have 2 issues.
A bad abs unit and hydraulic issue.

Do you? Maybe.
But that would be super rare to have both problems “at once”?

 

Well this is my 3rd ABS unit counting my original. I’m all honestly I thought I knew brakes but this Tacoma has 100% proved me dead wrong.

 

Wow……I missed the 3rd “ABS unit” part.
Now I’m really stumped………

 

Sorry. I’ve been that way for 4 months now. Thought I knew but guess again. Lol Yeah I was wrong. Not the first won’t be the last.

 

An for the hydraulic part I’m not sure about. My brake booster is air and my master cylinder is just brake fluid. It doesn’t have hydraulics hooked up to it. But once again I might be wrong. Lol

 

What is the plug-in that goes to the side of the master cylinder? Where does it go and watch it do ? It’s like plugged in to the side of the reservoir.

 

might have missed but for the wheel sensors, are you sure you put them in the right spots? Also did you ever change any wheel bearings? May be unrelated but I had issues with the same code we had swapped in 2 left wheel bearings and the sensors did not like that. we replaced the harness and sensors and it only went away when we put in the correct right. We did it as its easier to carry 1 wheel bearing off grid than 2 which will work just won't work with the ABS. Try replacing the harness too if testing that if you have not.

Figured toss that in there if you find your ABS is fine. We went back and forth for a few weeks before just going back to OG setup format (net new wheel bearing again).

 

Well now I’m even more freaking confused. LOL. Well I didn’t change anything but the wheel speed sensors. I honestly thought I put everything in right.

 

They only go in “one” spot.
Once they are plugged in, the go to “separate” pins on the Skid Control ECM.
You can not really get them in the wrong spot.

 

Ok then. I got them right. Well at least I hope I do. Lol

 

The brake fluid level sensor.
The brake light will come on if the fluid is low.
The same brake light as the E-brake uses.

 

Nothing wrong with hoping…..
I’ve done lots of thing based on “Hope”.
Sometimes it works out ok. Other times not so much

 

Th

Thank you. I figured it would have been another relay or something like that I didn’t know about

 

I’m about to Fred Flintstone this son of a gun.

 

ok lets not confuse you any further if you only replaced the sensors and they are all in the right spot then you should be good to go on that front.

 

I’m semi invested in this now.
I’m going to go back and read through all the post.
See if we missed a a clue or two.

Dm93 is going to be the head on this operation.
He does this for a living.

Me? No, no me.
I just fix stuff once it’s broke.
But sometimes guys like me, who know just enough to to be dangerous, can point out the obvious that gets over looked. Or have ideas just dumb enough that “work”.

Anyways, I’ll see what ideas I can add to this.
Let me read over it all again.

 

Guys I definitely appreciate the help I really do.

 

Start with what we know and when it happened.
We know you have ABS codes, and that the ABS module is activating the ABS.

This all started after hitting a BIG pothole.
(Was the pot hole hit with the right wheels?) - (You have codes for those wheels)

Also, did you replace any wheel speed sensors?


With fuses installed:

C0210 - Rear speed sensor RH circuit
C0278 - OPN/Short in ABS Relay Circuit
C1235 - Foreign object front FH sensor
C1241 - Low/High Battery voltage

Without fuses installed

C0278 - OPN/Short in ABS Relay Circuit


What to try (maybe)?
Your scanner has the ability to read wheel speed and wheel direction.
I’d start with a short drive while monitoring those data pids.

 

Never hurts to check voltage drop with a load (in this case a headlight) on the circuit although usually this isn't necessary as most of the time a bad circuit wouldn't even light a headlight even though it may still show battery voltage on a meter with no load applied.
Being the circuits load test good I can see no reason the C0278 is setting other than a pin fitment problem or faulty ABS module although I still think the low pedal is a separate issue.

Well I mean we can't rule out the master cylinder without being able to cap off the lines and see if you have a firm pedal.

Excellent reacp and good suggestion.

I would assume this would be obvious but I have to ask at this point, there are no obvious fluid leaks anywhere correct?

 

A little more digging and I looks like pulling the ABS fuses doesn’t kill the ABS unit completely.
There’s still a power at pin 46.

Does this make a difference? Probably not.

Also, when all the fuses were installed.
Did the ABS come on instantly when the brake pedal is pressed?