ScottR

Hi

I'm new to this forum and new to 964s, so hello!

I got my 964 end of Feb this year and am enjoying it

However, I seem to have an ABS problem. I've tried a few forum searches but can't seem to find ABS problems the same as mine, so here goes:

My ABS works intermittently!

Generally, if testing it either doesn't work at all or it works for the first one or two tests and then won't work.

The wheels lock up and it goes into a slide - I'm assuming the ABS should kick in at this point!? This has got me into a bit of bother, so am keen to fix it!

I have no warning lights to suggest there is a problem.

It's just been a through a full service and no faults show up on the diagnostics.

I've had the ABS relay replaced.

The control unit has been tested on another car and is OK.

I'm told the sensors look like they could do with being replaced - but why would it work and not work? Is there any way of testing the sensors for sure before buying new ones to no avail?

So, can anyone shed any light/point me in any direction?

Cheers
Scott

RicardoD

Kent,

Do you have a C2 or a C4?

Ricardo

colo964

Having bad sensor probably will show up on a diagnosis. Having dirty sensors might not unless the car is rolling.

I've pulled my sensors and had about 0.5 cc of metal filings on the ends of the magnets.. Cleaned them with a Qtip; it's a free inspection. Give it a shot.

ScottR

It's a C4

ScottR

Oh OK - so it IS possible to pull the sensors, clean them and put them back? The garage told me that they'd pretty much ruin them by pulling them so I'd need new ones?

Sten

They're held in by a small hex headed (Allen?) bolt. There are usually only two possible problems removing them:-
1. The head of the bolt corrodes so your Allen key won't fit (pass the Dremel and replace with an ordinary bolt)
2. The sensor is corroded into the housing.

If you're going to take them out, give them a good dose of penetrating fluid a few days before. While you're in there, check that the teeth are all stiil there on the ring around the cv joint. If you measure the resistance of the sensor, it should be in the range 800-1200 ohms. Use some copper grease when you refit them.

ScottR

OK, thanks.

I think mine are quite corroded, so that may be the problem. But I'll have another look and see what's what.