Urgent, 4runner dead after 2 wks of no use

[Legender]

I'm sure you're aware... just because you change a fuse or replace something the codes won't automatically reset when you turn the vehicle back on. Either need to reset with OBDII tool or disconnect the battery for a bit and let it start over.
Hope you can get to the bottom of this soon.

 

[simple]

Relay is in the engine bay fuse box, look for the same-sized brightly colored relays - blue , green and pink - lined up next to each other. Blue is the ABS MTR and Green is the ABS SOL. Don't try to interchange these relays for testing purposes, the pinouts are different.

There is a bunch of harnesses going to the abs module, I would disconnect them all prior to swapping any relays/fuses. Re-connect the harnesses one by one and see if if anything blows.

If someone has a better way to do this I'm sure they'll chime in.

Okay, I'm tracking what the relays are. My local dealer has an extra MTR relay. Do you think it's worth picking that up and just swapping it out in addition to the fuse? I'm not sure what I'd even be looking for when I pull that relay as far as being bad or anything.

 

[earthrealm]

Good you have narrowd it down. when i had a solid abs light on my dash. it was a blown 40amp fuse that was the culprit, swapped it, and abs started working, making a buzzing sound when the brake pedal is depressed

 

[Seymore Butts]

Even if there is no power to the braking system, whether due to a relay, fuse, or even a complete failure of the pump+CPU, you should still retain braking functionality, even though it won't be with power brakes. The OP reports complete lack of braking using the pedal!

 

[AuSeeker]

Even if there is no power to the braking system, whether due to a relay, fuse, or even a complete failure of the pump+CPU, you should still retain braking functionality, even though it won't be with power brakes. The OP reports complete lack of braking using the pedal!

This is what puzzles me, I would think there would be some brakes only without power assist.

[MENTION=19984]simple[/MENTION] are you saying you have no brake pedal, as in the pedal goes all the way to the floor?

 

[simple]

This what puzzles me, I would think there would be some brakes only without power assist.

[MENTION=19984]simple[/MENTION] are you saying you have no brake pedal, as in the pedal goes all the way to the floor?

This has also puzzled a lot of the people that I’ve talked to. And yes, the pedal goes to the floor, and in drive, I idle along forward. Same in reverse. But when I step down on the parking brake, it engages and the vehicle stops.

I have not tried to pump the brakes to see if I get anything there. I also got a few 40a and 30a fuses from a junkyard today. I’m going to replace my 40a ABS MTR fuse tonight and see what that does.

I did talk to the dealer and the parts guy was able to locate an ABS relay for 70 bucks. But thought I might get it from a wrecked 05 in the junk yard. The fuse box didn’t have the 3 relays mentioned earlier, and I’m actually pretty sure that mine doesn’t either, because my fuse box diagram has 3 empty slashes where the blue pink and green ABS relays are. So maybe that’s an 03-04 thing or potentially a canadian 4runner thing?

 

[ElZilcho]

If the pedal goes to the floor there is a mechanical failure somewhere. I can't think of any combination of electrical issues that could cause this.

My opinion is to trouble shoot this from the other direction. Start with the mechanical issue and backtrack. Had it not been for the the dead battery (and some ancillary issues associated with it) the brake pedal would be the headline and not the warning lights.

 

[simple]

Welp, Good news and awful news. So the brakes do work, but they're super degraded and I have to really stand on the pedal to get the vehicle to stop. I was able to make the trip home without issue, listening to the ABS alarm the whole way.

I've also made things considerably worse on other ends. I think I fried something else. My check engine light is back on, my speedometer doesn't work, and I have a p0500. My VSC lights are no longer flashing which I take it is also a bad sign as that's probably fried too.

Before i swapped the 40a fuse for the ABS, I connected my car to techstream and got,
c1223
C1253
C1256
B2221
B1241

The fuse blew when I reconnected the battery and the battery sparked. I'm so awesome at this. Thats when the p0500 problems started.

So at this point I know I have to replace the Master Cylinder Assembly, it sounds like its actually not that hard. I called the Toyota Dealership and they quoted me 3k for the part. I didn't even ask about labor. That's clearly high, but there's not much I can do about that price.

If I decide to do it myself, looks like I can get a used one for about 4-500 bucks. And then I have to figure out my speed sensor issue.

What do you guys think? Is it worth it to try and replace the master cylinder assembly myself? I've changed out shocks and springs, changed pads, calipers, and rotors and have done other small jobs, so I don't know how this will pail in comparison.

Fudge me....

 

[Seymore Butts]

How do you know that you have to replace it? Just get the vehicle properly diagnosed before you throw more parts at it.

 

[simple]

How do you know that you have to replace it? Just get the vehicle properly diagnosed before you throw more parts at it.

Based on other threads with pretty much the exact same issue. The short that’s blowing my 40a fuse is supposedly from a fried ABS computer. Those codes I pulled with Techstream.

But you are right. I’m looking at calling my insurance tomorrow and see if my comprehensive coverage will cover freak accidents like this. That would make it easy to just drop off at the dealer.

 

[Seymore Butts]

Let me save you a call to the insurance company: no chance.

I think your problems are way too complicated to diagnose on a forum.

 

[Ncbenz]

Before you go an replace the master, get the power brakes working again. Without power brakes on a hydro boost system the pedal will go really low. The power steering fluid is actually the coupling between the pedal and the master. So when there is low ps fluid your pedal will go very low before you hit the master cylinder.

 

[simple]

Before you go an replace the master, get the power brakes working again. Without power brakes on a hydro boost system the pedal will go really low. The power steering fluid is actually the coupling between the pedal and the master. So when there is low ps fluid your pedal will go very low before you hit the master cylinder.

Then wouldn’t my steering be very heavy? I figure my power brakes don’t work because that 40a ABS fuse keeps popping

 

[Ed_C]

Odd seeing "B" (Body) codes on the list, quick google results in tailgate related switches.

What does techstream show for battery voltage with the engine running? Toyota ECUs act screwy when voltage is low.

How is the rodent population there? Something may have been snacking on your vehicle wiring.

If a properly working ABS modulator etc. loses power while the vehicle is running, it should still allow you to brake normally except no ABS. Before replacing any electrical components need to find out why they're getting short circuited in the first place (why I mentioned the rodent thing). You need to get a factory service manual and electrical wiring diagram and go through the diagnostics sections, they do show what connectors etc to probe and what the results should be. What you could try for the time being is disconnect every electrical connector to the modulator and see how the brakes work. Do it somewhere without a lot of traffic and other obstacles.

There is no power steering fluid flowing through the brake system,Hydroboost is a GM design for vehicles that couldn't produce enough vacuum @ idle for regular vacuum brake boosters.

 

[simple]

Thanks again to everybody who has commented. Everyone has been very helpful and insightful.

So significant progress has been made. I ended up risking it and getting a used Junk Yard ABS system for 400. Ended up having a mechanic do the install since it was only 300 and that was worth not dealing with the install pain myself. So I'm 95% back. The lights are all gone, brakes are normal, and running techstream does not show any open codes despite about a 15min drive home. The p0500 is gone and my speedometer and ODO now work.

My only remaining issue is my VSC. When I turn the key to 'On' and it does the lamp check, the VSC lights work. Thats more than I got before I replaced the master cylinder assembly. I initially thought I may have blown the lights on the cluster itself, but know now that's not the case. However, I can't get the VSC lights to illuminate when I press my VSC off switch, or when I shift into 4lo or lock the center diff.

Any ideas on what to look at here?

 

[Drunner97]

Thanks again to everybody who has commented. Everyone has been very helpful and insightful.

So significant progress has been made. I ended up risking it and getting a used Junk Yard ABS system for 400. Ended up having a mechanic do the install since it was only 300 and that was worth not dealing with the install pain myself. So I'm 95% back. The lights are all gone, brakes are normal, and running techstream does not show any open codes despite about a 15min drive home. The p0500 is gone and my speedometer and ODO now work.

My only remaining issue is my VSC. When I turn the key to 'On' and it does the lamp check, the VSC lights work. Thats more than I got before I replaced the master cylinder assembly. I initially thought I may have blown the lights on the cluster itself, but know now that's not the case. However, I can't get the VSC lights to illuminate when I press my VSC off switch, or when I shift into 4lo or lock the center diff.

Any ideas on what to look at here?

Pull the grey plug off the master (it's the smaller one) then turn the rig on and see if the vsc light illuminates. Should trigger the abs, vsc, and trac lights. If you need a pic I can go snap one.

 

[Drunner97]

This one. That should disable all the nannies and trigger your lights.

Sent from my Pixel 2 using Tapatalk

 

[S p a r k y]

Dude that sux, hope you get it all going soon! Did the new cluster arrive back to you?

 

[simple]

This one. That should disable all the nannies and trigger your lights

Great call! When I unplugged it, the lights illuminated and stayed on, but I when I plugged it back in, I can’t get it to turn off via the VSC Off switch. Or when I shift into 4wd with center diff locked.

 

[AuSeeker]

Great call! When I unplugged it, the lights illuminated and stayed on, but I when I plugged it back in, I can’t get it to turn off via the VSC Off switch. Or when I shift into 4wd with center diff locked.

Test the switch, with all the electrical issues you have had the switch may be bad and stuck in the on position.