one front speed sensor or two?
 

Good morning,

new to MBWorld... wanted to say thank you all in advance for any help or suggestion you may have.


HISTORY:
this all started a week ago. car was parked all day. started it in the eve and started to drive away but acceleration just died. pressing the gas had no effect. car would not move then ESP light came on. i parked and googled the issue. found a video explaining how to turn off ESP. turned it off then was able to drive home.

can someone tell me how many front wheel speed sensors there are on a 2014 W204 C250?
should there be one or two?

the dealer told me "both front wheel speed sensors need to be replaced" i purchased 2 sensors from the dealer and decided to replace them myself. I started on the front passenger side and replaced that one with no problem. but when i got to the drivers side... i see that there is no sensor there. there isnt even a threaded hole for mounting the sensor (like there is on the passenger side). what i do see are the brackets that hold the sensor cable... as if there should be a sensor there, but with no threaded hole for mounting (no hole at all) how can there be a sensor on that side? why would the dealer tell me that both need to be replaced?

im so confused

UPDATE:

used my own OBDII scanner to read codes (after i changed the pass side sensor)... got 2 codes: replace right front speed sensor & replace left front speed sensor

erased codes with scanner

warning lights on dash will not go off: SYSTEM INOPERABLE. SEE OWNERS MANUAL; ESP LIGHT; TRACTION CONTROL LIGHT; ABS LIGHT

read codes again... 1 code: replace left front speed sensor (but there is no left speed sensor)

There is a sensor for each wheel......

I had the left front speed go bad, cleared the fault and all was OK for next 60mls but then fault returned. I spoke to an indi garage who said they would only use OEM parts and replace both fronts. I bought 2 from MB and fitted left front , cleared historic fault code all seems to be good. Have the spare if the right fails. The original fault was C0031. W204 2013 54k miles. Reading other forum comments it seem only OEM sensors work for long term service. Took about 3 hours to change but nice warm weather last weekend.