VW Polo 9N P0501

[ruffles1986]

I have a VW Polo from '03 1.4 16V engine code BBY, i am going crazy whit this car. The car have MIL on, and always same DTC code P0501 Vehicle Speed Sensor Range/Performance, i can erase the code, but after run some meters MIL came on again and same DTC code obviusly.

Always in Dashboard the speed is shown correctly, i meause value by OBD and is correct, but i measure value in engine control unit and there is the problem... the speed work well to 39km/h but after the speed is 0km/h the car give some pulls and MIL came On.

I check the wiring diagram and the speed sensor give signal to dashboard from Pin 6, and dashboard give signal to ecu by Pin 5, then if speed work in dashboard i asume a working sensor.
The mysterious is always speed cut at 39km/h and after go to 0km/h, if a reduce the speed the speed came again in engine ecu values, i try to disable cruise control because in some cars this work from 40km/h... but problem persist.

I replace the engine control unit and now i stay in the start point... MIL on again

some help please?

[ruffles1986]

I have a VW Polo from '03 1.4 16V engine code BBY, i am going crazy whit this car. The car have MIL on, and always same DTC code P0501 Vehicle Speed Sensor Range/Performance, i can erase the code, but after run some meters MIL came on again and same DTC code obviusly.

Always in Dashboard the speed is shown correctly, i meause value by OBD and is correct, but i measure value in engine control unit and there is the problem... the speed work well to 39km/h but after the speed is 0km/h the car give some pulls and MIL came On.

I check the wiring diagram and the speed sensor give signal to dashboard from Pin 6, and dashboard give signal to ecu by Pin 5, then if speed work in dashboard i asume a working sensor.
The mysterious is always speed cut at 39km/h and after go to 0km/h, if a reduce the speed the speed came again in engine ecu values, i try to disable cruise control because in some cars this work from 40km/h... but problem persist.

I replace the engine control unit and now i stay in the start point... MIL on again

some help please?

Is possible do DTC off in this ecu?

[maajkii]

what ecu is it??

[voltechcar]

pass pm, try

[ruffles1986]

what ecu is it??

Marelli 4MV

[ruffles1986]

finally i found the fault when i am near of go crazy... the speed sensor output from dashboard also goes to radio, the car have installed a aftermarket Radio-CD LG, and the radio by same pin have an output for Remote ON, this perturbed the signal.