2009 sprinter ABS lights wont turn off - help please!

[pinguheed]

Replaced front discs, broke sensor
replaced sensor, lights wont go out
Mechanic plugged in to Snapon sureTrack diagnostic -
Fault codes are 4418 - speed signal implausible
4428 -L6/1 Left front rpm sensor- gap between sensor and rotor is tool large
Above has been rechecked etc and quality sensor has been used.
Also the offending sensor sends fluctuating signals at standstill when the other 3 are stable at zero.
Mechanic seems to think its the ABS pump? Im not so sure as why would it suddenly just give up

Suggesrtions please are much appreciated....its already cost me £225 and got nowhere

 

[LostKiwi]

Forget the ABS pump.
Did you check the gap with the new sensor?
Did you fit a genuine sensor or a cheapie?

 

[pinguheed]

Sensor cost 55 so not a cheapo but not genuine

 

[pinguheed]

should i replace with genuine part??
Also do you know what the gap size should be?
thanks in advance

 

[Kev555]

check sensor gap on opposite side

 

[pinguheed]

Can anyone give me some advice please?, ive now replaced entire front hub- fault lights still coming up.
How do you 'check the gap'? A more informative answer would be very helpful

 

[Kev555]

Sorry Pinguheed was away for few days there. I meant check the gap on between the sensor and rotor on opposite side hub if you didnt know what i meant. Set of feeler gauges might help on checking gap if it isnt too wide. If the gap is right then it possibly a cheap sensor as Lostkiwi said or possibly sensor wiring on vehicle side faulty (stretched or broke during fitting?) Double check part numbers on sensor you got is compatible with new hub. Non genuine parts suppliers can supply a lot of ill fitting crap sometimes