Tracs /abs/wheel bearing

Hi, my tracs / abs light comes on now and again, when i stop the engine and restart it goes out , must be the 20mph check. However this only started when i heard a wheel bearing noise, only faint but definately there. Car has just passed its mot and i cant feel any play but it must a dry bearing. At first i read the forum and thought the abs ecu wanted re soldering and it might yet, but first i,am going to change the rear bearing hubs(both sides) and see if it puts the light out. My theory is that a slight vibration is setting off the sensor. Although the steering is perfect. However you would expect that with a rear wheel bearing. By the way car is a 97 v70 20valve with 106000 on the clock. Any views would be welcome. Cheers ian.

Hi Ian, First thing to do is get the error codes pulled. You really will be stumbling around in the dark until you can see what caused the ABS light to come on in the first place. If there are no error codes then one possible explanation (and your car is around the right age) is the ignition electrical contact unit. These wear and can misbehave giving this ABS light (as well as no horn, indicators or lights).

Abs/tracs light 

Cheers brian, i dont have a code reader or know anyone who has. I am not going to the dealer. You might be right about the switch, when i was out this morning, i started up and the lights came on, stopped and started again and they went off. The bearing needs changing anyway so i am going to do both sides at the rear along with discs and pads. I will then change the switch, i dont have any probs with horn lights etc. Many thanks for replying brian.

Hi Akabo, Your car doesn't have sensors on the rear hubs so wouldn't waste time on the bearings unless you can feel play . Symptoms sound as though the control board needs resoldering. Vibration even in the front wheels wouldn't give the symptoms you mention.

My fathers 95 850 had a front bearing away (bigtime) and it had no impact on the abs system at all. However my car a 98 s70, has a fault with the abs, light comes on at times, mainly when driving or after sitting idleing for a long period, ie traffic jams. Think its either the front left abs sensor or else the main abs control unit, suspect the unit as no one including Volvo can get a code out of it :(

I expect like many before you and many after you, your ecu has dry joints.... I would deffo get the codes read and swap whatever sensor is highlighted for one known to be good before wielding the iron tho...... Cheers Jod

High Ian, try this ,I had the same prob on my 04v70d5 take out the centre caps in your wheels(front) you will see a bolt about17mm check that both of these are tight!!! one of mine had come loose and was trigering the the fault abs tracs ect, hope this helps kind regards Adey

High Ian try this, ihad the same problem on my 04V70D5 a nice bloke gave me this tip and it cured it. Take out the center caps in your front wheels, you will find a 17mm bolt, this atatches to the drive shaft, check to make sure they are tight, might be a long shot but it cured mine!!! hope it works for you kind regards Adey

Hi. I have a 98 C70 T5 with 107000 km on the clock. Sometimes the cluster ABS/Tracs light flashes (one or two seconds only) but systems continues to work perfectly. Concomitantly with the flasing of both lights, the amplifier of the sounds stops working (the soud systems continued to work, but with no sound). One or two seconds latter, evething returns to normality. After reading forum topics, i think that it looks like the ignition switch. Can anyone help? Tks.