Hello,

I own a 1998 V70 base model. I have been experiencing unusual issues with the ABS system.

It started acting up when I would apply the brakes while turning sharply, like turning into a parking spot. When I did this, the ABS would activate.

Now the ABS is activating often, when I am in a stop/start situation with heavy traffic, slowing down for a stop light, it will kick in when I get to a low speed. It also sometimes activates when i am not touching the brake pedal, I can hear the system pump and when I apply the brakes I can feel that the system is active.

Has anyone had experience with this? I do not want to buy a module if this will not fix the issue, and I am too cheap to pay for the overpriced dealer diagnostic, but is that the best bet? I have my local wrench check the sensors and he said they were OK and suggested the module next, but could not guarantee that it would work.

Any help or suggestions would be helpful, Thanks for your time,

Barry

 

Start by researching teh ABS system. My understanding is the V70 will allow you to pull codes on the vehicle using no scanners. My 740 is a 1990 model, so I don't have that luxury but cars a couple of years later do.
Hint, I have been working on my own cars for 20 years and after 12 months, I have finally reached a good understanding of teh ABS system in my car and have the ability to diagnose and fix my particular model. So expect it to take some time.
Why not pay the dealer to diagnose it? They will have the correct tool for the job, the experience and the workshop library to identify the problem.
Throwing random parts at something always costs more in the end and unless you have the knowledge required, you are going to have to either pay someone or spend teh time to learn it yourself.


Regards, Andrew.

 

why were my comments deleeted. they were fact and the public should know i didnt swear and can back it up

 

They were deleted because you made 8 posts saying the same thing in various posts. You were slamming Volvo's and quite frankly after reading 8 of the same thing I deleted them.

 

i only wish i had stopped by this site before i took a bath on the 01 v70 turbo that took my *** to the cleaners. this site is very helpful in letting people now yo better have lots of money to always be fixing the beast. now i am sure volvo makes great trucks and more likely the new ones when bought new and kept uner warrenty ,traded in ,and buy again you will be fine. but i had NO idea they were this bad. if you read what is written here how can you not fell this way. if you are a family guy living paycheck to paycheck a used volvo is not for you. i paid 9500 for an 01 v70 turbo. 2 weeks later headlight are going taillights are going abs mod going. i was way over my head and should not have bought this car. back in the shop cost me 130 for the volvo dealer to tell me i should part ways with this car. the dealer said that! like i said if you are an enthusiest and have money go for it. but if you dont buyer be ware. i do not want anyone to go through what sound like several have. i got 2200 for it on a trade in.

 

hopefully that is a more fairer comment to make

 

Did you have a full inspection done first?
Second You over paid for the car to begin with.
Third I think you got a Lemon one they are not all like that.

 

Aside from the insignificant additions my my initial inquiry .......

I am wondering If anyone has had a similar problem with the ABS actuating when it is not supposed to? The system kicks in under light braking, the wheels are not locking up and it only happens at slow speed. I am just looking for some idea if a replacement module would fix such a problem, or if it might be an individual wheel sensor? It costs approx. $150 for a diagnonsis and i would rather not do that if i can get away with it repalcing it with a used part for a fraction of the price.

Thanks for any help I can get

 

When the ABS module went bad in my sons 850 we didn't notice anything like the problems you are having, it just simply stopped working. It sounds like yours is going bad, but maybe at a slower rate than a complete failure.

I still think that most likely it is a module going bad and replacing it could fix the problem. Go to www.bbareman.com and do some research and maybe contact them to see if they can give you any additional information.

 

The module in my wifes 850 activated like that when it went bad.

 

The module is rarely a problem in any computer system, it is usually bad information in or power supply/ground issues.
More than half of the troubleshooting problems in the greenbook for ABS on a 740 for example, are to do with bad sensors and wiring. About a quarter are ground/power supply issues and maybe two or three fault charts go back to the module itself.
They either tend to work or not. When they don't work they light the warning lamp, if it's intermittent it is likely a sensor or wiring. Power supply/ground issues tend to make the ABS system disable itself. The ABS comupter has a very good self diagnostic process on initial start up that also looks at the ABS pump. If it doesn't like information it gets from teh pump, the ABS computer's grounds or positive power supplies coming into teh module or ABS pump, it disengages the system and lights the lamp. Intermittent faults like sensors are dealt with by keeping the system active and only warning if intermittent faults by flashing teh lamp.
I would certainly not buy a module as I don't think it's the issue.
I would however, pay to have it diagnosed by a specialist in ABS systems if you are not competent to do it or don't feel you could do it.
It will not cost any more than a brand new module and you will be certain a critical safety system is functioning correctly.

Regards, Andrew.

 

On the 850 and up since 1996 the ABS modules go bad all the time. The solder joints for the pump motor and ABS sensors crack and make the faults like which are described in this and many threads about the ABS problems.

They rarely have a bad sensor unless someone has left the wire untied and it has rubbed a wheel or the car has hit something that cut the wire.

The modules can be rebuilt for about $100.00 or it can be opened by someone and repaired that can remove the module and open it and resolder the joints. There is a walkthrough about repairing it as well on the forum.