wheel speed sender output

[dnb]

What does the wheel speed sender "look" like electrically?

Does this drive the speedo (and odometer) directly, or is this fed from the ECU... (If it's from the ECU, then what does the ECU output look like?)

eg 5v TTL square wave with 8 cycles per prop shaft revolution...

Thanks

[spend]

Different variations have been used. LT77 box driving ecu + sensor on front of diff --> sensor on output of diff with signal split electronically to supply speedo & ecu.

I seem to remember you saying your car was a Serp/T5/BTR so probably the later 'sophisticated version' (way over my head!)

Dave

[dnb]

Thanks You're right with the serp/T5/BTR

[shpub]

The waveform is a sq wave that may or may not vary between 0 and 12 volts. It is not TTL. Can be very difficult to see unless you have a scope and the wheels are moving reasonably quickly.

Severl pages on this in the bible BTW.

[dnb]

Needless to say the Bible version 2 that I haven't got yet...

The problem's been solved now anyway - it wasn't the sender.

[red griff 500]

On the SD1 type, the voltage swings between @0.7V to @7v. It does this 5 times per revolution of the wheel (4 times per revolution of the sensor).The wheels do not need to be moving quickly because the output is held either high or low, and you can see it switch with a very slow speed.

Steve