Brakes: 850: ABS & Traction

[G33M4N]

I have a '96 850R and it has an intermittent, but regular, ABS/Traction issue.

Randomly, and quite often, the Traction & ABS lights illuminate on the dash. As an aside, when they randomly light up, they knock Cruise off if I'm on the motorway too.

Sometimes, the ABS unit will also trigger/vibrate for no reason at slow speeds, even if I'm not braking. It will also randomly activate if I am braking at slow speeds as well.

I've checked the rings, replaced two of them, cleaned the sensors and it's still playing up.

Am I correct in thinking the ABS unit itself needs looking at? If so, what's the process involved for this?

Thanks in advance!

[winsox]

have you still got the airbox fitted in the car ?

Do you lose speedo ?

[G33M4N]

Originally Posted by winsox

have you still got the airbox fitted in the car ?

Do you lose speedo ?

Standard airbox fitted.

Don't lose the speedo.

[winsox]

Originally Posted by G33M4N

Standard airbox fitted.

Don't lose the speedo.

Make sure that the HT lead is clipped into the holder if its not it can interfere with ABS sensors.

if its not this you will probably have the Dry joints in the ABS module.

You can remove the black plastic control section and still drive the car whilst its being repaired.

You wont have speedo or Cruz as the signal from the ABS is used for speed. (there were some that didnt but only a few)

[Willow place]

Will disconnecting the control section extinguish the ABS light ?

[Cookeh]

Originally Posted by Willow place

Will disconnecting the control section extinguish the ABS light ?

No, it will trigger it.

[Simmy]

Originally Posted by G33M4N

I have a '96 850R and it has an intermittent, but regular, ABS/Traction issue.

Randomly, and quite often, the Traction & ABS lights illuminate on the dash. As an aside, when they randomly light up, they knock Cruise off if I'm on the motorway too.

Sometimes, the ABS unit will also trigger/vibrate for no reason at slow speeds, even if I'm not braking. It will also randomly activate if I am braking at slow speeds as well.

I've checked the rings, replaced two of them, cleaned the sensors and it's still playing up.

Am I correct in thinking the ABS unit itself needs looking at? If so, what's the process involved for this?

Thanks in advance!

abs unit will need resoldering they get dry joints its one of the most common repairs on the 850s folowed by failing heater matrixes and rust on the wings

[DaveNP]

Dry solder joints in the ABS unit is a common failing, it is where the solder cracks on the circuit board causing a poor contact, from personal experience and looking at it on the web it's often the pins for the socket where the connector plugs in, which makes sense as the plug would vibrate when the car is used and cause fatigue failure in the solder. You could try a bodge fix which is to wedge something (like a bit of folded thin card) between the connecting plug and the body of the ABS unit, it pushes the plug enough to one side to make contact again.