CV Joint = ABS Fault?

[goldsabre]

I had my ABS light come on the other day and the computer voice telling me.. "automatic braking system is faulty, please consult Renault dealer bla bla bla..." I searched the forums and found some very useful info on how to check the connections etc but to no avail. I then discovered a thread on testing the ABS sensor with a digital multi meter. When I got to the front drivers side wheel I noticed a load of grease around the rubber gator and splattered on the inside of the wheel which I never noticed before!!! Could this be linked to the ABS fault?

[madnoel10]

Most probably. The wheel bearing has a magnetic ring which spins past the ABS sensor - if the magnetic field is blocked then no signal is generated. If you connect a multimeter to the sensor and spin the whell you should get a pulsed voltage read out. A clean up and a new boot clip and a repack of grease may solve the problem.

[Phaeton]

Originally Posted by madnoel10

If you connect a multimeter to the sensor and spin the whell you should get a pulsed voltage read out. A clean up and a new boot clip and a repack of grease may solve the problem.

Sorry bit of a thread hi-jack, I didn't think you could test ABS pickup's with a Multi-Meter I thought they produced a sine-wave which could only be detected by a 'proper' machine.

Alan...

[madnoel10]

The effect of the magnet passing the coil of the ABS sensor should produce a small fluctuating voltage - down in the millivolt range. It a rough and ready check.

See link below for some info.,

http://www.topbuzz.co.uk/maintenance...esting_abs.htm

	Ignition Coils Ignition Coils An ignition coil (also called a spark coil) is an induction coil in an automobile's ignition system which transforms a storage battery's 12 volts to the thousands of volts needed to spark the spark plugs. This specific form of the autotransformer, together with the contact breaker, converts low voltage from a battery into the high voltage required by spark plugs in an internal combustion engine. In older vehicles a single (large) coil would serve all the spark plugs via the ignition distributor. In modern systems, the distributor is omitted and ignition is instead electronically controlled. Much smaller coils are used with one coil for each spark plug or one coil serving two spark plugs (so two coils in a four-cylinder car). These coils may be remote-mounted or they may be placed on top of the spark plug (coil-on-plug or Direct Ignition). Where one coil serves two spark plugs (in two cylinders), it is through the "wasted spark" system. In this arrangement the coil generates two sparks per cycle to both the cylinders. The fuel in the cylinder that is nearing the end of its compression stroke is ignited, whereas the spark in its companion that is nearing the end of its exhaust stroke has no effect. The wasted spark system is more reliable than a single coil system with a distributor and cheaper than coil-on-plug. Where the coils are remote mounted they may all be contained in a single moulded block with multiple high-tension terminals. This is commonly called a coil-pack.

[goldsabre]

Cheers for that. I did at first suspect that a wire had been pulled off during a recent service as the light came on about 50 yards down the road from the service centre!!! I am taking it to a Bosch service centre tomorrow to have a diagnostic and get them to have a look at the cv boot. Hope it's not too expensive!!!

I'll let you know the outcome...