Question about 1998 Volvo V70
Thanks Ginko for your quick response. I did as instructed. Battery disconnect for approx. 1/2 hr. Reconnected, set time on dash, checked ODB codes with my 'Scanguage' and none found. ABS light still on. What should I try next?
This solution is for every car owner with an ABS problem (e.g. Brake System Warning Light).
1)ABS warning light comes on occasionally while driving, warning light turns off next time you start the car, eventually the light comes back on if you drive long enough
2)ABS light comes on seconds or minutes after starting or even moving your car
3)ABS sensors have been replaced, ABS controller has been replaced, and ... the problem returns, sometimes soon, sometimes later
4)ABS warning light refuses to act up in front of your mechanic
5)ABS mechanic has no idea what is wrong
6)ABS brake have no leaks to be found, the brake fluid levels are normal and the brake pads pass inspection but the light comes on
My solution will not solve all ABS system warning light problems, but it may solve very many and save many dollars.
This solution just isn't Standard Operating Procedure in our day to day service repair shops as it is time consuming fault elimination. Why is it overlooked, who knows? It should also, in my experienced opinion, be the absolute first thing checked, by the book, before any sensor, control module, brake fluid, brake bleeding, whatever your mechanic suggest... the list goes on for some car owners. The point is, if this isn't checked first, all bets are off for the DIY or even the certified mechanic.
To get my point across to every car owner and MECHANIC will require GREAT effort on my part otherwise this information will be ignored. Now, back to my point, unless this check is made before any car "computer" throws an error code is taken into account, then that error code can be misleading. No ABS red warning light on the dash of all cars or trucks everywhere can truly be CERTIFIED in testing if this process isn't first completed. The odd exception might be the ABS control unit was on fire, you drove the brakes down to metal or some other freak accident. Here's where I say, "for just $9.95, you, can buy this instruction book". Nope this is FREE and will save many people from having nightmares considering the millions of car owners.
Have you ever heard, "A chain is only as strong as its weakest link"? Well, in the real world, ABS errors are almost always misdiagnosed in first repair attempts. The very first thing that should be performed is a visual inspection inside the engine compartment and brake area. Unless there is an obvious loose wiring harness plug, a lost kitten, distorted/bent brake lines, worn out rotors or brake pads, or something else screaming for your attention; then close the hood and step away from the vehicle and put down that silly diagnostic computer. So, now that the hood is closed, we are going to jack up the car and take off a wheel. Once a wheel is off, we need to disconnect the brake caliper and hang it to the side out of the way. Yes, this is usually a painful, very greasy and dirty process; front wheel and four wheel systems are even more fun. Start with the front wheels and work your way around. Now, and only now is it possible to check each Wheel Bearing Torque value. However, just checking the torque with a push and pull of the rotor disk isn't always sufficient. The hub axle bearings and bearing seats need to be inspected, bearings repacked and then precisely torqued. And when I say precisely, in some rare cases that can mean putting all the parts back together, driving the vehicle, tearing the wheel back down and checking the torque settings again. In some cases; hub, axle and wheel bearing assembly just can't maintain this torque value and still rotate properly because just one of the 3 parts may have some flaw, and this leads to rotor movement. It is also very easy for an experienced mechanic to get it wrong. So, it is good to do it right the first time but that also does not mean it always can be done correctly the first time. As good as any mechanic or auto production line worker may be during assembly of these components, all of these bearing components will never "seat" the exact same or show identical performance. They just try to do their best with what they have.
Basically, the ABS electronics are not the weakest link in most cases. If you have proven beyond doubt that the axle bearings are as close to 100% of factory torque settings and the bearings are healthy and lubed, then the weakest link has been removed. Only then should an ABS error code be used to diagnose a possible electronic component failure. All that this axle bearing nonsense means to those still wondering is that the ABS sensor ring will no longer be deflecting off axis as it spins or sits inside the rotor hub. If the hub/ABS sensor ring tilt off axis just a fraction of an inch on some vehicles, the gap between the sensor and ring is affected, and this will trip the ABS warning light. These ABS systems were designed to operate within a specific set of tolerances and unfortunately the bearings in your axles will not always cooperate. A pot hole here, a curb there, too much hard cornering and braking; sometimes that is all it takes to just slightly loosen an axle bearing and have virtually no noticeable effect.
That is my 2 cents the ABS problems, thanks for reading.
Posted on Apr 15, 2009
99% probability it is a bad ABS module. Extremely common on these Volvo's. Speed sensor would probably show up on your generic scan gauge, ABS module would not likely show anything. You can get your module rebuilt by sending it in to a number of places. Do a google search for Volvo ABS Rebuild. Victor Rocha is a reputable source for this.
Posted on Apr 06, 2009
ABS problem is mostly on the sensor, check all the sensors for damage, if its all ok check your abs control module check the wiring and the terminals. spray some wd-40 on it then let it dry for a couple of minutes. the return ,if same problem occurs maybe your abs module is not working well
Posted on Dec 10, 2014
Wheel sensors are most common to go bad. they are easy to check. Just unplug jack the car up and have someone spin the wheel, use a oms meter to check miliamps. You see these wheel sensors are like Minnie generators, they send a signal to the module which tells that the wheel is turning. Make sure the tone rings are clean, a leaky wheel seal will cause a dirty sensor. Good luck. If you check these and they are good then go to the module
Posted on Jan 04, 2015
I agree 99.9%. my dealer charged $hockin$ for 2 wheel speed sensors, then changed story and wanted to charge kick a$$ for another abs control module. I said i would pay so long as the thing worked. it didn\'t! After a long story and fighting back and forth on man hours spent, i finally got the car same way it went, minus the new stuff that stupid joe gets billed for. Last week a backyard mech suggested to check the wheel bearing! Well, come over to my place, i said... many cans of beer one saturday later, the fella blew my biscuits away! He fixed it! just 2 new wheel bearings, new set of brake pistons and voila! i got me a new buddy and problem fixed!
Posted on Jan 04, 2013
2002 silvaredo abs light stays on
Posted on Aug 01, 2011
Most of the peep here have great ideas and knowledge, I however side with ' atp1962 ' I have fixed many others on domestic vehicles that were absolutely plugged up with grease/ oil and lets nit forget that they are magnified....meaning the sensors collect tiny bits of metal particles from grinding pads into nothing but metal to metal, hence the sensor " groves" become plugged up.
I don't prefer the WD40 concept but love using starting fluid which is an alcohol based cleaner that evaporates quickly. Also use air pressure to then blow anything sticking to the sensor off till it's as clean as new.
It is true that bad wheel bearings can cause these pesky problems, but You'll hear the Howling of the bearing or by shaking it briskly if it's loose.
Just remember to start w/ the simplest approach first for it will usually save $$$$ and time.....and less grey hair.
Posted on Feb 04, 2015
Make sure the scanner you are using is capable of scanning ABS codes on your particular vehicle. I can't tell you how many times I had to rescan a vehicle using my scanner and found an ABS code. Retrieve the code and let us know.
Posted on Jan 16, 2015
You will probably need to find a mechanic that has a good scan tool. It should have little cards that they change for your car. this will tell you what component is damaged. had similar problem with a Suzuki and it took a few different mechanics to find one with the right tool. if light stays on you most likely have a bad part.
Posted on Nov 27, 2014
More than likely speed sensor on the passenger side front hub, ( AUSTRALIA) not sure LHD. HAD THE SAME PROBLEM IN MY XR8 BOSS 5.4 FORD FALCON UTE ( pick up ). $ 65 WITH LABOUR....Kipper
Posted on Nov 09, 2014
Apply scanning tool to establish the real cause
Posted on May 06, 2014
The knowledge you share really changes me in life, I sincerely thank you for what you have done, surely your blog will help more people.
Posted on Jul 18, 2019
Does any one why the ABS, brake and light come on and off when slowing down and when stop no light in BMW X3. I have change the rear sensors, brake pad and sensor, O ring in rear, transfer case gear and oil but the problem persist. Is not giving any code on scanning. Although I notice when reversing the back parking sensor beep funny and at time it beep even you are off the rear gear.
Posted on May 28, 2018
You need a abs scanner to check for codes. You can also reset light. The regular brakes will still work. The function of abs is to keep brakes from locking up and causing a skid in emergency braking. This will keep your vehicle easer to control.
the most likely problem is a wheel speed sensor. Have it scanned and you will know what the problem is. You will need a abs scanner a regular obd scanner will not work.
Posted on May 30, 2017
A OBD2 scanner will not read ABS codes unless it specifically is listed in the specs of the scan tool.
Posted on Jan 11, 2017
Head on over to advance automotive and they will check your obdII abs codes and tell you why it is on for free
Posted on Jan 06, 2016
Hello, did you get your issue solved?
Posted on Jun 26, 2015
You need a special scanner for abs which can be purchased at autozone or maybe they can do it for you. My guess is wheel speed sensor brakes will work fine just not the abs
Posted on Apr 15, 2015
35 years as a Volvo tech and most of the answers posted here are complete bs. If you have a code for a right rear wheel speed sensor that keeps coming back 99.9% of the time it is the ABS computer. This problem dates back to the early 90's. There is a circuit on the board in the computer that goes bad. Check codes. If it is RR wheel speed sensor replace the computer.
Posted on Apr 15, 2015
Abs motor is clog.
Posted on Mar 11, 2015
Almost all Volvo abs lamps are on because of a faulty abs module if vehicle has good wiring to abs wheel speed sensors. I am not sure the long post is supposed to help anyone but provide a vent for frustrated fixya members.
Posted on Feb 03, 2015
I don't know why its not setting a code, but maybe your reader isn't advanced enough to retrieve it. It sounds like you have done most everything a person would expect I do find the other answer of proper torque on the wheel bearings interesting however here is my simple check, sometimes because of worn wheel bearings perhaps your tires aren't quite worn equally and these things together can aspirate the problem so before spending money look at your tire tread and check the air pressure if a wheel is slightly smaller then the other one and especially after a corner the imbalance in induced voltages in the sensors will trigger the abs light. My own vehicle set a code when the pump failed.
Posted on Nov 04, 2014
Resetting your "computer" or ECU won't do anything to clear ABS fault codes. Nor will scanning your codes with a standard OBD II reader. You need to goto a good independent volvo shop (or the dealer) which can read your ABS codes ; and send you hunting in the right direction.
Posted on Oct 21, 2014
RESET YOUR COMPUTER, BY DISCONNETING THE POSITIVE CABLE AND THE NEG CABLE AND HOLD THEM TOGETHER WITH BLACK ELECTRICAL TAPE FOR 5 MINS. AND THE COMPUTER WILL REST IT SELF. It's the easiest fix and most mechanic's will tell you different. All they want is your money, as I have a '91 Lexus LS 400 with just about 500,00 km's and hasn't failed me..
Posted on Oct 21, 2014
Your abs pump is bad replace it 200.00 dollars
Posted on Oct 10, 2014
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Posted on Jan 02, 2017
SOURCE: ABS light stays on
one guy say to take it to a brake place and have them scan it .
you also can call auto zone or advance auto and see what they say and see if they have a way of scanning it
Posted on Feb 06, 2009
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