V70 Brakes: Anti Skid Service Required

[supaFlaj]

Hi guys,

I know this has been discussed alot, but my situation is different.

Volvo V70 D5 164hp 2003 year
Yesterday while driving on motorway, 10 minutes after starting, at about 80 mph suddenly Anti Skid error came up with amber triangle and ABS light. When stopping I turned off the car and after turning it back on, error disappeared, triangle disappeared, but the ABS light stayed on until I drove for a few meters, the it disappeared also.

Today same story happened on the exactly same location on motorway and disappeared when doing the same as yesterday.

I noticed that when the error pops up there is a slight change in temperature and the fog appears on the road.

Does anyone have some ideas what could be the reason for such behavior?

[cheshired5]

https://youtu.be/77sntnVpyvI

[supaFlaj]

Thank you, I will check those things later today.

This could be it, because I also get some strange feeling in the brake pedal, when streering is turned fully left and brake is applied.

Will report back.

[petey]

I'm not saying absolutely what that is, but I suggest it is the pump as that's exactly what I used to get.

When the under bonnet temperature got over a certain level, to the point that in the summer on my route home, it was ALWAYS come on at the same point in the traffic jam, the light would come on. By default, any ABS failure will always stay on until at least the next power cycle.

When it cooled down, one of the two worded warnings would go away, and once I reached 5 miles an hour or so, it would all go out.


The actual problem, if I am correct, is that there is insufficient voltage across the pump in the ABS unit. One fix is to remove the ECU from underneath the valve block, cut open the ultrasonically welded case and test for dry joints on the circuit board.
The other option, and pending mileage, the more likely one, is to remove the pump magnet pack / cover, making sure that the bush on the end of the rotor stays between the pump elements in the valve body. Almost certainly, you'll see carbon dust everywhere as the brushes will have failed.
Then pull the rotor out, using a puller, remove the bearing, and then you can get to the brush plate with its brush retainers. 20 notes and 3 days later, I received my existing brush plate with new brushes soldered in and it all went together and never a problem since.

(I happened to have a scrap VW Touareg hanging about, and like most of the German cars, it uses a very similar ATE ABS unit. The VW spec has a bearing at both ends of the rotor, unlike the Volvo one which only has a bush in the magnet pack / cover. I simply liberated the rotor and magnet pack, obliterated the part number on the outside as that seemed a little unfair on the next poor sod and bought myself another 200,000 miles of trouble free ABSing.)

[supaFlaj]

Originally Posted by cheshired5

https://youtu.be/77sntnVpyvI

Thank you, this worked, left side was unscrewed for 4 rounds, I have tighten it and tomorow I will take it for a test drive.

[supaFlaj]

Unfortunately, the error reappeared. Later I found out, that because the bolt was unscrewed for a few months it affected the reluctor ring for ABS sensor. The ring was cracked and when replaced, the error message went away.