Speed Signal

[jamie]

I have noticed a few posts concerning errors related to the Speed Signal.  For reference, I scoped it today and found it to be 10Hz at 1mph, the picture shows the signal "held" when car was at around 50mph.  (2000 3L with 17" wheels, assume its the same for all wheel sizes and adjusted at the speedo side via tech2).  Interesting as it suggests a slight error with Speedo reading 50mph and signal suggesting 51.9mph  


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[Marks DTM Calib]

Is it realy only 6V peek.....

[Marks DTM Calib]

Ow yes....what does it read when stationary...?

[TheBoy]

The MID is set with pulse/km (the 5 digit number if you hold both S and R for a second or 2). Presumably speedo get same signal?

[jamie]

It can read around +12V!!, 0V or 6V at standstill.  I can understand why it can be high or low.  Strange though why it swings up to 12V at standstill sometimes and sometimes 6V  

So its not possible to really check with a DVM, a capacitor, LED and a couple of resistors could make a simple go/nogo tester.

[Marks DTM Calib]

It can read around +12V!!, 0V or 6V at standstill.  I can understand why it can be high or low.  Strange though why it swings up to 12V at standstill sometimes and sometimes 6V  

So its not possible to really check with a DVM, a capacitor, LED and a couple of resistors could make a simple go/nogo tester.

Blimey.....they let the output float....surprised there is not a weak keeper on the output or at least one of the inputs!

[jamie]

Or of course, mine could be damaged, but the swing is good enough for everything to work.

I will check the signal today on another car, if possible.