Can I drive with a malfunctioning ABS?

July 30, 2009 10:04 PM

Is it dangerous and/or damaging to my car to drive with a malfunctioning ABS module?

I have a 2000 VW Beetle. Several months ago my brake pedal started making "sproingy" noises and sort of jerking/kicking back when I braked at slow (10 mph) speeds. I took it to the dealership and they replaced one of the ABS wheel sensors, and told me that if the problem continued I would probably have to replace the whole ABS module. It's still doing it, but over the last couple of weeks it has been getting much worse and more regular. The brakes seem to be working fine, but it's unnerving and annoying to have my car making noises and jerking every time I come to a stop. With 75,000 miles on it, I'm reluctant to keep pouring money into my car, especially the ~$1,500 it will cost to replace the ABS. Is this something I can just ignore?

posted by Dilemma to travel & transportation (18 comments total)

My ABS control unit went wonky on my car, but I didnt have any noises or jerking. I drove it for a while with no issues for several months (except for my speedo not working occasionally). I'd imagine you'd just have no ABS.

You can try getting the module repaired which costs from $200-300. Most places will give you a refund if they can't repair it.

I went with modulemaster - others on the car forum i frequent recommend them. (I have no affilliation).
posted by wongcorgi at 10:14 PM on July 30

Another recommended company is BBA reman

Also FWIW, a new ABS module for my car (BMW) from the dealer was only $800 (+labor to code it to my car). Either your dealer is trying to rip you off, or VW modules cost way more.
posted by wongcorgi at 10:18 PM on July 30

Several months ago my brake pedal started making "sproingy" noises and sort of jerking/kicking back when I braked at slow (10 mph) speeds.

Let me get this straight: ABS is kicking in when you're not in a slipping/skidding situation? ABS produces pedal vibrations and buzzy noises while it rapidly pulses the brakes, to avoid locking the wheels in a skid. Is this what you're feeling?

It seems to me that this is an unsafe condition for your car to be in all the time. If you're on dry pavement, your braking distance is going to be reduced by this unnecessary pulsing of the brakes. Also, I'm not sure how durable ABS mechanisms are, but I assume they're not built to be used in every normal braking situation, every day.

I'm curious: Can you disable ABS altogether?
posted by knave at 11:17 PM on July 30

Correction: ...your braking distance is going to be reduced increased...
posted by knave at 11:18 PM on July 30

You should step back and take a look at the question: Is it dangerous to drive a car with malfunctioning brakes?

You need to suck it up and fix this. Is it safe to drive for a couple of days? Yeah probably -- it doesn't rise to the level of a ball joint breaking and wheel falling of at speed -- but you should find someone who can fix it for a reasonable price, take the car to them, and get it dealt with. If it gets worse and fails completely, you could find your brakes locking up in a low-traction, hard-braking situation, which can have serious consequences for you and others on the road.

$1500 does sound like a lot, though. So before you go back to the dealer, find a good mechanic and have them take a look and give you an estimate. You should be able to get this fixed for less than that.
posted by dseaton at 11:23 PM on July 30

With 75,000 miles on it, I'm reluctant to keep pouring money into my car

Really? If you take care of it, your car is hardly middle-aged. You're not so much "pouring money into it" as you are replacing things that will eventually go bad over the life of the vehicle. If you were to get a new car, you wouldn't be solving this problem so much as postponing it at the cost of a new car payment and higher insurance rates.
posted by toomuchpete at 11:32 PM on July 30

wongcorgi: I've looked online, and it appears that the VW units do cost more (about $1,200). To have it repaired, I noticed that some places require you to remove it yourself and mail it to them. Is there any way to get it repaired but have someone else remove it? (I know nothing about cars.)

knave: Yes, that's what I'm feeling/hearing.

Just to clarify, my brakes aren't having any problems, even when the pedal feels like it's fighting back. My car still slows and stops just fine.

Do cars really need ABS? I know they used to not have them.
posted by Dilemma at 11:42 PM on July 30

Some vehicles have a button which simply switches ABS off; I don't have access to a full owners' manual for your car, but this webpage has an excerpt and makes it look like there might be a switch on the dashboard (marked 13 in that manual) labeled "switch for anti-slip regulation".

You could check your owners' manual and see if your car has such a switch, and your manual's description of what it does, as it might disable ABS.
posted by Mike1024 at 12:10 AM on July 31

Just to clarify, my brakes aren't having any problems, even when the pedal feels like it's fighting back. My car still slows and stops just fine.

Do cars really need ABS? I know they used to not have them.

Have you ever driven a car without ABS?

The problem is not straight line stopping distance. Under some circumstances, that can actually improve without ABS. But, for the most part, straight-line stopping on hard surfaces is identical for ABS and non-ABS brakes.

What anti-lock braking allows you to do is maintain control of the car during sudden braking. It allows the steering wheel to have some effect. If you're doing 60mph on clean dry tarmac and slam on the brakes without ABS, no amount of turning the wheel will deflect your path in the slightest. You'll plow straight on forward. If the road is sandy, or gravelly or wet, the speed at which you observe this effect drops drastically. On ice, without ABS, you only have to be going about 10mph before it's impossible to steer during hard braking. Or, alternatively, if you swerve at speed before braking without ABS, you'll likely spin right the fuck out.

With ABS, you can steer and brake simultaneously. Neither is as good as one on its own (you split available traction between steering and braking). But, it does allow you to, say, brake and swerve away from the deer on the highway.

Now, if you're an experienced driver of non-ABS vehicles, you can mitigate all of this considerably. If you don't know what you're doing, the difference in safety between ABS brakes and non-ABS brakes is the difference between day and the dark, gooey center of a galactic-center black hole.

On the other hand, that jerking/fighting is the ABS system engaging. If you braked hard on ice, that's precisely what you should get: BAK BAK BAK BAK BAK BAK BAK BAK, with the pedal slamming into the bottom of your foot. So, what you're actually getting is ABS all the time. If you drive like a granny, this may not be an issue. If you're drive fast, at the edge of traction, through curves and need to moderately adjust your speed, having the ABS system kick in at the wrong time can send you into a spin.

I'd get the sucker fixed. Your brakes are operating abnormally. That's never good, dude.

Some vehicles have a button which simply switches ABS off; I don't have access to a full owners' manual for your car, but this webpage has an excerpt and makes it look like there might be a switch on the dashboard (marked 13 in that manual) labeled "switch for anti-slip regulation".

No. You are dangerously confusing "traction control" with anti-lock braking. The traction control system does use the ABS system to do its job. But on no modern car I know, other than race-prepared vehicles, is there a switch to turn off ABS. The reason that there's no switch is that ABS brakes are categorically better than non-ABS brakes in all foreseeable road driving situations.

Only a race car driver, during an actual race, is better off without ABS.

Also, I'm not sure how durable ABS mechanisms are, but I assume they're not built to be used in every normal braking situation, every day.

They're plenty durable. It's just a solenoid-actuated valve in the path of the hydraulics. You press down on the pedal, it pulses open and closed, regulating the pressure. The ABS system releases pressure; it doesn't produce it.

It does have a service life, like everything else, and you are shortening its lifespan by overusing it. But, it's not designed to be expendable (like an airbag or bumpers or whatever). They're designed to let you drive your car on ice all winter and sand all summer, if that's what you do.

I'm curious: Can you disable ABS altogether?

You can yank the fuse. You'll return to non-ABS mode.

And if you're used to driving an ABS car, you will have learned the wrong driving techniques to handle the "new" brakes under difficult conditions.

Although, really, given the number of people who call into CarTalk and freak out about "this loud pounding sound, like my car's being shaken apart, when I hit the brakes hard, what's wrong!?!!!1oneeleven", I don't think most people learned any techniques for handling under difficult conditions.
posted by Netzapper at 1:06 AM on July 31 [5 favorites]

Dilemma writes "Do cars really need ABS? I know they used to not have them."

It varies by implementation. However many cars rely on the ABS system to provide power assist (my buick was like this, the abs pump went and we lost assist) even in nonlocking stops. So if it fails you could be left without assist. If that happens unexpectedly your first stop is going to be quite a bit longer than normal possibly causing you to rear end another motorist or blow through an intersection.
posted by Mitheral at 1:12 AM on July 31

I feel your pain- the same thing happened to my '98 Volvo last Summer. I found a web site providing super-clear instructions on replacing the control module, and I was able to find a replacement at a junkyard for $100 (vs the $400+ for a new one) 20 minutes later I was back in business. It was dead simple.

It might be worth poking around online for various combinations of '2000 VW Beetle ABS Module replacement howto'. $1500 does seem like a lot (and that's coming from me as a Volvo owner!)

(IANACM - I Am Not A Certified Mechanic.)
posted by usonian at 3:33 AM on July 31

GET IT FIXED. The ABS module in your Beetle is designed to communicate with other modules in your car's network. Restore that function since its failure could be causing problems unseen to you. The data that is useful to the ABS module is likely useful to other control modules and their proper interaction is an absolute necessity. This isn't just jamming something in the door to keep a window up. This directly involves the safety and functionality of your vehicle.

Unfortunately, replacing it yourself is not an easy thing to do. You'll have to use a VW computer to bleed the air out of the system and code or program the module.
posted by Jon-o at 4:10 AM on July 31

A friend of mine has had "random ABS issues" for the last year or so that the mechanics kept telling him they couldn't figure out, but it was probably okay. Last weekend he totaled his car when the system failed completely on the highway. I wouldn't screw around with it.
posted by olinerd at 4:32 AM on July 31

Yeah, I have to agree with everyone that you should get this addressed ASAP. I drove my dad's old Jeep around for a couple of years with an ABS that had been recalled unbeknownst to me. I had a few instances of what you've described, but ignored the problem (stupidly). One day, half-way through a cross-country trip, the brakes locked up and I had to pulse the emergency brake to stop the car. My heart was pounding and my hands were shaking, but looking back I consider myself *extremely* lucky that it happened on a flat stretch of highway, instead of during that hailstorm the day I crossed the Rocky Mountains.

I ended up leaving that car in Ohio at a junkyard because it was 14 years old and had 150,000 miles on it, and I couldn't afford to pay the $1500 to get it fixed when the car was worth probably $500. I rented a car to get home.
posted by fancyoats at 5:19 AM on July 31

i had the same problem with my subaru legacy. the dealership had difficulty ascertaining what was wrong, so i just yanked the fuse and drove without abs for a year or so until the car developed another annoying and expensive problem to fix.
posted by lester at 6:46 AM on July 31

Some vehicles have a button which simply switches ABS off; I don't have access to a full owners' manual for your car, but this webpage has an excerpt and makes it look like there might be a switch on the dashboard (marked 13 in that manual) labeled "switch for anti-slip regulation".

That's traction control! No car that I know of has an ABS on/off switch.

It will be fine to drive, as long as you consider that you don't have ABS. In certain situations, as others have stated nicely above, braking could be compromised.

Go to an independent shop, source used parts, and you can probably cut the price in half. With my BMW, I had a stability control sensor go out---$1000 at the dealer to replace---and I found a European parts specialist online, found BMW's own how-to, and replaced it myself with a used part for $150. Just do some digging. There will be Volkswagen experts out there who will be glad to help out. Find a Volkswagen forum and seek some help.
posted by luckypozzo at 7:29 AM on July 31

Do not pull the fuse to stop the pulsations as a stop-gap.

Modern braking systems are designed with the understanding that ABS is better than human reactions for every reasonable use case of a road-going car. This means that, under hard braking, the brake booster is "spring loaded" to force the braking system into engaging ABS in a panic stop. This means that if you disable the ABS, the design of the system will make it much harder to modulate the brakes, even if you know what you're doing. This "problem" of modern design has been repeatedly verified by people who pull their ABS fuse for track days during One Lap of America.

Fix the problem, do not pass Go, do not collect $200.
posted by TheNewWazoo at 9:15 AM on July 31

Thank you, hivemind, for talking some reason at me. You've convinced me; I'll get it fixed!
posted by Dilemma at 1:56 PM on July 31