traction sensor signal lost...

[stevieturbo]

The old P8 ecu used to record wheel speed only when TCS was active ( at least I think it did, as I know I had issues with it at one point many years ago )

But the S series definitely logs wheel speeds all the time

The only time Ive lost signal on mine, is if a sensor has broken, or when launch control is active. When it's active for some reason it substitutes the calculated driven wheel speeds onto a single wheel instead. Once launch de-activates, normal wheel speed logging is resumed.

[nikfruit]

You mean activate, or the time you are using it?
Because i have it always active but sometimes using it..

[nikfruit]

I need to solve this problem because I activate data log by undriven wheel motion . So no switch for toggle because now I use ana2..before I was toggle on the switch of data log and never stop indicating the vss signal.so when loosing the vss signal no boost correction appears by gear pwm modifier.

[stevieturbo]

So exactly what is the problem again ? And what steps have you taken to try and fix it ?

And has anything changed ?

[nikfruit]

I edit the above post

[stevieturbo]

Yes, but that doesnt answer my question.

[nikfruit]

So exactly what is the problem again ?= The problem is that the ecu sometimes stop indicating the vss signal. And what steps have you taken to try and fix it ?= I didn't try to fix it because I don't know how.

And has anything changed ?

the change is that I deactivate the log switch because I use the ana2.

[nikfruit]

I edit on your post

[stevieturbo]

So do you lose speed signal on logging ? ( upload a relevant datalog )

Do you lose speed signal on real time display ?

Do you lose signal on all 4 wheels ? Or just one wheel ?

When viewing diagnostic screen, is signal lost completely or are pulses still counted ?

Are there any specific circumstances it happens ? Is it the same every time ?

[mefmotorsport]

Mine does something similar, Just using GT101 on front underiven wheel, picking up on back of 5 wheel studs. It works fine then suddenly I loose the pulses (software count stops on UDL), If I stop the vehicle for a few seconds then when I move off its all working again, perfect! as soon as I get up to say 70-80mph it just stops agian.

Ive checked the wiring of the sensor, cant see how it can be faulty, why should it fix itself after stopping. Its as if the pulses build up and overload it! maybe I'll increase the gap as the stud ends dont protrude much above the surface of the hub.

But, since I want to install full traction control, I need to do all 4 wheels so I'm trying to get some abs sensors to work using using the built in wheel bearing pulse generator, using the JBPerformance dual VR circuit board that I bought a couple of years ago, its looking good on the oscilloscope on my test setup, nice square waves, will try it on the car once I get the correct/suitable fitting abs sensors.

Martin