speedo, mileage, trip computer not working

[andy_p7777]

My car is a 2002 172 with abs

Replaced all 4 abs sensors and cleaned the rings up with fine sand paper the rings are fine just a small corner chipped off 2 of the teeth front n/s which doesnt look like it would affect it...

Clocks work fine done the dancing dials trick.

also stereo wont increase with speed

plugged my code reader in for the 1st time the other day and it said

"PO500 vehicle speed sensor A malfunction"

is there a way to reset the ECU?

Anybody had the same experience?

 

[Sean6545]

Look for broken/rotten wires in the connectors in the relay box behind the passengers headlight.

 

[andy_p7777]

just checked the loom in the engine bay and all seems well. is there a certain relay for the abs system anywhere that i could check?