[charlesleo74]

Background: my brother gave me a 2005 Sienna LE van and it’s been a project finding out what needs to be fixed. The car sat around for a year, but they didn’t treat it too kindly either. Still doesn’t explain some of these things that I’m seeing.

Just wondering if you had any ideas or guesses as to why this would happen and if so, any solutions.

Problem: at a very slow crawl when I step on the brake the pedal intermittently jumps and jerks suddenly at me in succession as if there was some back pressure. Interestingly, it doesn’t seem to do this if I’m moving faster and come to a normal stop. Only when it’s coasting. Haven’t determined if it’s due to uneven surfaces, but it’s happened on relatively flat ones too. It also makes a HORRIBLE grinding/creaking noise only when this happens. ABS light doesn’t come on except when you first start the car (which is typical.)

What I’ve already done:
1. Checked the brake fluid levels. Been staying steady all along.
2. Bled the brake lines.
3. Replaced the front rotors and pads.
4. Replaced the drums, cleaned the hub assembly, and replaced the shoes.

I was hoping this might solve the issue, but it’s still doing it. It doesn’t happen often (1 out of 5 times going slow) but it scares the heck out of me. I’m starting to think it might be related to the ABS but the noise is baffling. It does feel like a crappy ABS kicking on (I hate it when my Prius Prime does this.) Parking brake works great. Brakes in general seem to be working fantastic.

Questions:
1. Could I disable the ABS/VSC by pulling the 64 and 65 fuses in the engine fuse box to test if it’s ABS related? Anything bad or would it be just like driving an older car pre-ABS? I’m assuming that if it stops this problem, then it’s ABS related.
2. Would my ODB scanner pick up on whether ABS was ever triggered?
3. I don’t recall seeing any dashboard lights when this, but is this typical of older Siennas?
4. I read somewhere that someone else had struts that were worn out and that this caused their vehicle to rock which led to this issue, but I’m not hearing it if I go from 35 to a normal stop.
5. Any other ideas as to what may cause this?
6. Is there an easy way to clean the ABS sensors if this is the cause? (I realize I can replace them but was waiting to hear back first.)

Thanks!

 

[3Wheelerguy]

Sounds like ABS is kicking in. Seeing that it sat around I can only guess that the trigger ring on the front CV shafts broke or debris is in there. Unless you have a good scanner it will not give you ABS codes. Yes you can disable the ABS. Unplug a sensor will trigger a code and system is diabled and you have 'regular' non ABS braking.

 

[charlesleo74]

The sensor is behind the trim so I was just looking for a quick fix (don’t have a garage unfortunately.) You think it‘s fine to just remove the fuses for now?

 

[slothman]

you need a GOOD scanner that it going to read ABS.

Could be ABS module, or sensors etc. Either way, not safe to drive it this way. For you, or others. Either get a good scanner to diagnose or take it to a qualified shop. End of story. Please stop driving the car.

 

[charlesleo74]

Sounds like ABS is kicking in. Seeing that it sat around I can only guess that the trigger ring on the front CV shafts broke or debris is in there. Unless you have a good scanner it will not give you ABS codes. Yes you can disable the ABS. Unplug a sensor will trigger a code and system is diabled and you have 'regular' non ABS braking.

I hope it’s not the CV/ring. I want to say no because other than this one very intermittent issue, it’s running like a champ. I might just replace the sensors, get a magnet, air gun, and some good light in there to better see what’s going on.

again, brakes are all working and are completely new as I just replaced everything myself. In reading more it’s starting to sound like just contaminated abs sensors or debris in that ring.

and fyi driving around without ABS is perfectly fine. For us older folks that had cars back in the 80s and 90s and lived in the cold Northeast with several feet of snow, our form of ABS was pumping on the brake pedal—something I still can’t get out of the habit.

 

[charlesleo74]

I’d also argue that if this issue was consistently repeatable, it might me a broken cog/CV. For example, if it was a cracked CV it would likely kick in the ABs at every slow stop from a slow coast. More likely to think it’s a dirty sensor or loose connection, or metal shavings in that CV.

Another way to look at the ABS fuses is that if it were so dangerous to lose that, then there wouldn’t be fuses for them in the first place. They’re melting on people all the time and it’s not directly causing accidents. It’s obvious that fuses go bad and it’s not the end of the world… so pulling them I wouldn’t think to test down a long driveway shouldn’t do any harm.

 

[slothman]

I hope it’s not the CV/ring. I want to say no because other than this one very intermittent issue, it’s running like a champ. I might just replace the sensors, get a magnet, air gun, and some good light in there to better see what’s going on.

again, brakes are all working and are completely new as I just replaced everything myself. In reading more it’s starting to sound like just contaminated abs sensors or debris in that ring.

and fyi driving around without ABS is perfectly fine. For us older folks that had cars back in the 80s and 90s and lived in the cold Northeast with several feet of snow, our form of ABS was pumping on the brake pedal—something I still can’t get out of the habit.

No. you are not understanding.
Your brakes will not work properly the way they were designed without the ABS. Stop avoiding the obvious issue. This isn't a car from the 80s or 90s. Everything works via computer controls.

If you get into an accident, YOU will be at fault, end of story. (moderator edited)

So as I said, get it fixed professionally, or get the PROPER ABS scanner. It's not the pads, and not the rotors !!!!!

 

[charlesleo74]

(Moderator Edited)

I have a ”proper” scanner. I obviously know it’s not the rotors, pads, hubs, and drum brakes because I completely reinstalled them myself.

I’m not going to pay $1,800 for something that can easily be cleaned or replaced with a new $20 sensor… That’s nothing to do with being cheap. I’ve seen plenty of ”professionals” that will take your money and are complete idiots. If you want a job done right, you have to do it yourself (unless you’re a complete moron.) Cars aren’t rocket science nor is it illegal to ask questions and get opinions from others on here… Have you met any mechanics recently??? Lol…

 

[BillG]

My van did this when the wheel bearing was totally shot. At slow speed braking, there would be an awful grinding sound from the front, right wheel. I had replaced the full hub/knuckle/bearing assembly with aftermarket (Moog) parts. My pads and rotors were freshly replaced at that time. My ball joints were replaced at the same time due to the bolt snapping. My half shaft was 2 years old and the rest of my front end (other than control arms) were 2 years old. My wheel speed sensor was only about 6 months old too. Well, the brand new aftermarket bearing assembly wore out in a few months and, when I would slow speed stop, the knuckle/hub assembly would shift and the ball joint would grind on the corner of the rotor.

 

[charlesleo74]

That sucks…

I’m fairly certain it’s front left which is why i replaced the rotors, calipers, and pads first.

I don’t completely trust aftermarket parts, but given the age of the vehicle and crazy costs, if I can DIY it without a lift and have the time I’m changing it myself.

Just bought direct fit for an entire exhaust system (3 catalytic converters) off of Amazon for $1k. Mechanic did the replacement for me for “free”—he sold the three old catalytic converters as the cost Of his service. But then he beaned me for a new rack and pinion and power steering pump at $2k… (felt I owed him this much since most mechanics wouldn’t work with parts that I bought.)

The parts suppliers are awful around here. A nearly same entire exhaust would run about $3k. A typical mechanic would charge $1,500 for $4,500 total. But I managed it for $1k.

He wanted $1,900 for new calipers, pads, rotors, and rear drums… My first time doing it but took about 1.5 days as I was extremely careful. Now I wonder how mechanics can rip people off (it’s just the going rate) on something so simple.

Also replaced my steering clock wheel in <2 hours (again first and hopefully last time.) $28 part but suppliers around here want $350-$500. Then a mechanic would probably add another $400 to this price tag…

If this whole thing was brought to a mechanic, I’d probably be pushing $8,000 in repairs already when used equivalents are around $5k and at least come with working sliding doors lol. The math wouldn’t be worth it. But I suppose at least I can say a lot of this is new.

I just took it down my driveway (usually enough to trigger it) and it did it about once in 10 paces back and forth.
Thinking I’d buy two front replacement sensors for $28 and replace them (could clean them but if there’s something wrong…) while I’m at it and inspect the sensor shaft/exciter wheel and clean it of debris. Hopefully the wheel isn’t cracked and the issue goes away. If not, it might be a trip to the shop for new CVs which around here is probably pushing $2k.

But yeah I was looking at drum hub replacement as they’re attached to the sensors. Doesn’t seem too bad of a job but still annoying after all this work. Mechanics and supply shops are awful in MA. I’ll see if replacing/clearing the front ones clear the issue first. I figure any mechanic worth their salt would want to replace those sensors (and all the brakes if they had the opportunity) regardless being almost a “classic” car lol.

 

[fibber2]

While I agree that the OP should get his van fixed properly (either with everyone's help here or professionally), let's keep the discussion civil. Thanks.

 

[BillG]

That sucks…

I’m fairly certain it’s front left which is why i replaced the rotors, calipers, and pads first.

I don’t completely trust aftermarket parts, but given the age of the vehicle and crazy costs, if I can DIY it without a lift and have the time I’m changing it myself.

Just bought direct fit for an entire exhaust system (3 catalytic converters) off of Amazon for $1k. Mechanic did the replacement for me for “free”—he sold the three old catalytic converters as the cost Of his service. But then he beaned me for a new rack and pinion and power steering pump at $2k… (felt I owed him this much since most mechanics wouldn’t work with parts that I bought.)

The parts suppliers are awful around here. A nearly same entire exhaust would run about $3k. A typical mechanic would charge $1,500 for $4,500 total. But I managed it for $1k.

He wanted $1,900 for new calipers, pads, rotors, and rear drums… My first time doing it but took about 1.5 days as I was extremely careful. Now I wonder how mechanics can rip people off (it’s just the going rate) on something so simple.

Also replaced my steering clock wheel in <2 hours (again first and hopefully last time.) $28 part but suppliers around here want $350-$500. Then a mechanic would probably add another $400 to this price tag…

If this whole thing was brought to a mechanic, I’d probably be pushing $8,000 in repairs already when used equivalents are around $5k and at least come with working sliding doors lol. The math wouldn’t be worth it. But I suppose at least I can say a lot of this is new.

I just took it down my driveway (usually enough to trigger it) and it did it about once in 10 paces back and forth.
Thinking I’d buy two front replacement sensors for $28 and replace them (could clean them but if there’s something wrong…) while I’m at it and inspect the sensor shaft/exciter wheel and clean it of debris. Hopefully the wheel isn’t cracked and the issue goes away. If not, it might be a trip to the shop for new CVs which around here is probably pushing $2k.

But yeah I was looking at drum hub replacement as they’re attached to the sensors. Doesn’t seem too bad of a job but still annoying after all this work. Mechanics and supply shops are awful in MA. I’ll see if replacing/clearing the front ones clear the issue first. I figure any mechanic worth their salt would want to replace those sensors (and all the brakes if they had the opportunity) regardless being almost a “classic” car lol.

DIY is the best, except that you have no one else to blame when something is screwed up and repairs ONLY seem to be required in Winter.

Before replacing sensors (for $28???), I would figure out what the actual source of the grinding sound is. It's not likely that the sensors are causing the grinding. It should be easy (look for shiny metal) to figure it out. I would suggest using Denso sensors, if you're already having issues with the ABS system. No point in throwing money at the problem by replacing potentially good sensors with cheap aftermarket replacements.

Replacing the rear hub/sensor is "super easy" except when you're in New England. I watched a YT video of the guy doing it. He hit it twice with a dead-blow and it fell right off. Having never done it before, I started with a regular hammer and a block of wood. Then, just the hammer. Then, a 2.5 lb. sledge. I finally broke out the cold chisel with the sledge to wedge it between the backing plate and the hub. I polished the heck out of the friction surfaces and put anti-seize on them, but, I assume I'll never have to do the job again.

 

[charlesleo74]

DIY is the best, except that you have no one else to blame when something is screwed up and repairs ONLY seem to be required in Winter.

It’s fun when I have the spare time. Not so much in the winter but repair prices on an old vehicle is insane around here.

So I got out the FR sensor. Was just careful about it. The sensor was caked in metal particles so I cleaned that off. Also sanded the surround outside area with some paper to catch debris in the hole. The inside of the exciter looked like it had bee sitting on the bottom of the ocean. Just dark pieces and lots of rust. I figured if this was a mechanic, they’d hit up with a brand new CV on both sides. Honestly, it was so full of stuff that I had no issue going in with a screw driver, swabs, a pen magnet, and brake cleaner. I cleaned it up pretty good actually—not factory new but it was pretty good improvement which made me think that a new CV won’t be necessary right now.

BUT, then I went to tackle the driver’s side. Spent a few hours just trying to get the bolt freed. Applied penetrating oil on several rounds, but it’s still stuck. Hammered it, filed it, even carefully torched it (sits on rubber), even used my impact wrench, etc. Looks like someone might have stripped it at one point. Either way, I gave up and put the wheel back on. Took it for a spin and it’s still doing it.

Not sure how to remove this frozen and partially stripped bolt now. At a complete loss. I suppose drilling is the only option? Just wondering if the penetrating oil I used is garbage.

Oh, and although it shows ABS fuses, there’s a clear plastic lid over those areas and I actually can’t even see if there’s a fuse in there. The whole row looks empty. So there goes that idea… I wish it was like a newer vehicle which has an ABS/traction button which quite frankly I turn off.

 

[sixto]

There’s a newer vehicle that lets you turn off ABS from the driver seat? Maybe traction control but not ABS.

Speaking of which, and I’m talking hypothetically, will the car run with the ABS pump unplugged? Will the system revert to regular hydraulic brakes with no ability for clumsy responses to wheel sensor input? There can’t be any other warning lights to illuminate or drive features to disable.

Sixto
‘04 LE FWD 207K miles

 

[charlesleo74]

I suppose I’m confusing it with my Prius Prime’s traction control then.

As for your other question—better left to someone who has tinkered with it before. But realistically, people AFAIK can drive with failed ABS sensors. It’s not like it cripples your car. So I assume it would be similar. I was just looking for a quick way to tell if it was the ABS kicking in.

As for removing that bastard of a bolt, I just watched Todd on Projectfarm and ordered up some Gibbs and a bolt extractor set…At the very least I own some new tools lol.

 

[Brian60]

Problem: at a very slow crawl when I step on the brake the pedal intermittently jumps and jerks suddenly at me in succession as if there was some back pressure. Interestingly, it doesn’t seem to do this if I’m moving faster and come to a normal stop. Only when it’s coasting. Haven’t determined if it’s due to uneven surfaces, but it’s happened on relatively flat ones too. It also makes a HORRIBLE grinding/creaking noise only when this happens. ABS light doesn’t come on except when you first start the car (which is typical.)

Do you get the grinding noise when turning the wheel or just when braking? What about accelerating? I had a similar bad grinding noise and vibration with braking, accelerating and turning the wheel. It was worse at slow speed. Took it to a shop and they replaced both struts but did not completely resolve. Turned out to be a bad front axle.

 

[charlesleo74]

Ouch. It's only when braking above 5 mph but no greater than 10 mph. Seems to be left turn mostly coming from the left side. Grinding noise might be an inaccurate description. Rapid clunking which appears to be common with ABS. Also, other people with faulty ABS sensors are reporting almost identical issues. It really does feel like an ABS issue.

Interestingly enough, it was triggering at one point when I was going in reverse and braking but ever since I replaced the drum assembly, that has completely stopped.

Not to say that it can't be something else, but I just need the bolt extractor to get here and some time to take that wheel off again and clean the sensor area. Who knows too - might even see a crack in there. I bought some aftermarket sensors and will also install them. I'll still keep the old ones around just in case. If I had to take it to a shop they'd probably hit me with replacing those as well as the entire CV.

 

[charlesleo74]

Update: Still can’t get the left ABS sensor out. Bolt extractors came and bolt extractor chewed up the head. So I took my favorite heavy duty screw extractor and worked on it then the screw extractor snapped off into the bolt… Couldn’t even make a dent on the broken off screw extractor.

So I called up my mechanic and admitted to cheating on him with myself… Have to take it in this week or next.

Have to say, there’s a little bit of a winding type of noise AFTER what I assume is the ABS kicking in and the car comes to a stop. Seems to be a relatively common problem overall with these sensors just getting dirty. I’m hoping this is the issue but it really could be a wheel hub failing. Someone else mentioned it in this post:

https://mechanics.stackexchange.com/questions/88027/feels-like-abs-kicks-in-when-braking

 

[tackdriver56]

Sorry to see that you broke a screw extractor off in the hub.
a) My '06 Sienna had the same low-speed ABS activation, which was annoying, but didn't really hurt anything.
b) The root cause was rust flakes forming between the sensor body and the hub casting. They increase the distance between the sensor and the tone ring, reducing the signal amplitude, so the computer thinks the wheel is stopped and activates the ABS.
c) I was able to remove the bolt, but the sensor was rust-welded into the hole. I had to destroy the sensor get it out of the hub.
d) after cleaning the hub and hole surfaces down to bare metal, I coated with anti-seize, and installed the new sensor, which completely solved the problem.
e) if you are able to remove that stuck bolt, (maybe by welding onto it? Or annealing it with a torch and drilling it out completely, re-tapping) you should be fine, following the above.
f) you could also consider buying a compatible salvage-yard hub/knuckle, but that's a lot of work to swap.
h) if you haven't yet destroyed the sensor, you can simply put up with the low speed ABS activation. IMHO, it's merely an annoyance, rather than a safety hazard.
Keep us posted!

 

[charlesleo74]

I have an update that it may have been solved!

But first to reply, the main issue is that I wasn’t sure if it was crud in the knuckle giving off false readings. It could Have been the the ABS pump (unlikely), the bearings/hub (possible although it would drive funny perhaps even squeal), a faulty sensor, worn struts when braking causing a misreading, cracks in the Exciter, or possibly something wonky with the CV.

What confused me is that there’s no ABS light coming on when this occurs. Maybe 2005 and earlier models didn‘t show the lights coming on when it was activated?

Yeah I could probably live with it, but knowing how my family took care of their stuff and I have two little kids under 4, it wasn’t something I wanted to chance. I did think about hitting a junkyard but I keep thinking the next step will be something quick then it turns out to be a whole day over one stupid bolt lol.

Appears that most of the time it’s simply related to gunk on the sensors or in the exciter which leads to misreading. It’s so close to the CV joint in the knuckle that liquids can get up in between and on an older car lead to metal flaking and rust.

I’m almost positive now that this is the case. I ended up removing the sensor by cutting the stripped hex head off with a plunge saw. However the bushing was completely welded to the bolt, so I ended up cutting the boot of the ABS with the saw towards the bushing. I was hoping to be able to reuse the sensor, but the boot really frayed—might be reusable but I have a generic that I had lying around in case it was the sensor. It took forever with vice grips and penetrating oil, but I finally managed to remove the bushing.

As for the stem of the bolt, it’s still sticking up. I kept trying to hit it with penetrating oil and tapping it with a hammer. Sanded the heck out of the area. Still NOTHING. Probably did this a dozen times today. Finally I just torched it with a regular propane torch, let it cool a little, then hit it with more oil. It seemed to suck up the oil but it’s still not budging. Will let it sit and wait longer. I’m not betting on this. Probably going to have to drill it out and tap it…

As for the exciter, it was FULL of metallic shavings and rust buildup. I took a screw driver and got in there, cleaning each gear and hitting it with brake cleaner and a pen magnet. Took forever (while waiting on the built oil) and then I took a pass with qtips.) I finally decided I’d spray some penetrating oil in there for extra measure. It’s not thick like dielectric which can collect junk but wet enough it probably will get shot out the hole in the back.

Now the sensor had shavings all over it. It’s funny because people report the sensor breaking off. For me the sensors have been easy and the bolts have been the nightmare. This last one I pried it up gently with two small screwdrivers then hit it with penetrating oil. Waited, then gingerly went around it working it up. I’m keeping the sensor just in case,but put it off to the side for now.

The generic replacement unfortunately is too short. I made it work by reusing the old cable hangers. Also checked to see if turning the wheel would stretch it too much. I just popped the sensor on the knuckle for now, then just zip-tied it to hold it in place. It’s not a good seal by any means nor is it secure to drive, but should keep junk out for now until I get more time to try getting the bolt out again or tapping it.

For sh1ts, I took the car up and down the driveway to test it about a dozen times. I figured the ABS light would be lighting up because the wonky (and temporary) zip tie but it never did. I’m shocked. Or maybe those lights didn’t light up with these models. Maybe the sensors have more leeway than I had imagined because I thought they were super sensitive to the slightest movements. Appears that just the gunk causes this issue in many cars, mostly older ones. I still don’t know 100% but I almost always trigger it and this didn’t. As for the noise, I did hear a faint“winding noise” when braking, but am beginning to think this might Just be related to older struts or something else when the car shifts its weight,

The lesson I’m taking away is that with newer and older vehicles, it’s probably worth removing the sensor every couple of years, quickly blowing it out with an air compressor, taking a pen magnet to it and giving the rotors a quick spin, then reseating the sensors. This should just be part of general maintenance and it is safety-related as well as fuel economy. It’s also something I’ll consider looking at if I ever buy a used car in the future.

Now if i have taken it to an average mechanic, they probably would‘ve hit me for new brakes and drums ($1,900), new sensors ($800), new knuckles ($1,000), new hubs ($250) and quite possible new CVs ($1,000.) Granted this turned out to be a total PITA with the bolt, but the money I saved on this 2005…