Checking for an ABS fault today, I thought that I would take the car for a drive whilst logging the speed signals from each front sensor. In the advanced measuring blocks there are two sets for each sensor, on the first ones the speed was indicated as expected to the cars actual speed, the second set showed 1 or 2km/h constantly, regardless of speed. Why?, and what am I missing?

Might help if we knew exactly what kind of ABS module you had.

-Uwe-

It was on a MK I Octavia. In the advanced blocks where you tick what you want measure there are two distinct groups of speed from the two front and two rear sensors, i.e two groups of four. What speed does the second group measure? These were giving the constant 1 and 2 km/h. Are the blocks available dependent on the type of module?

What speed does the second group measure?

Not sure. I've seen lots of ABS modules where all four "wheel speeds" in the second group read 255 km/h with the vehicle at a full stop. I've never really paid attention to that group with any vehicle while it is in motion.

Are the blocks available dependent on the type of module?

They certainly can be, yes. If you want us to do any digging, we'll need details.

-Uwe-

MVB 002 shows the start speed on these ABS modules, which means the 1st speed signal that was received by the control module is being shown there. The current speed is always in MWB 001.

A current version of VAG-COM "should" tell you that in the group heading.

Thanks, that has answered my question.

A current version of VAG-COM "should" tell you that in the group heading.

It didn't, but then I was selecting from the advanced blocks (ticking the check boxes), next time we have one I will have a look in the normal blocks and see what the headings are. It did its job as I was after more data to verify that the RH speed sensor was at fault even though we had replaced it before last July. We did replace it again and the customer reported that all aws OK.

Am I glad that the only integrated circuits in my car are in the alarm, radio, CD changer and the interior lamp dimming relay.

In the Felicia auto scan file I have added address word 41 for the diesel electronics.

That is a very impressive piece of software.

It didn't, but then I was selecting from the advanced blocks (ticking the check boxes), next time we have one I will have a look in the normal blocks and see what the headings are.

Will take that as a hint and see if we can find an easy solution to show the description in adv. meas. blocks too.

In the Felicia auto scan file I have added address word 41 for the diesel electronics.

Thought we added that before 607.3, but you're right that was right after. However, the next version will have that address listed by standard - thanks for mentioning.

That is a very impressive piece of software.