Date registered: Jan 2018
Vehicle: '04 S500 4Matic
Location: Toronto, Canada
Mentioned: 4 Post(s)
Quoted: 44 Post(s)
ABS engaging all the time
I had a similar problem before but since replacing my brakes it's been OK. Over the last couple of days I have started to get the vibration/hum through the brake pedal at low speeds. Even without my foot on the brake I can hear the pump running from time to time. It's getting really bad.
Tonight I plugged in the SDS setup and went for a drive monitoring the RPM values from the speed sensors.
The front left was always a little bit off and would be slower to react to changes in speed, but nothing substantial. After a little while the reading from this sensor would say '--' instead of a value. Only very briefly, but it was doing it.
There are no codes or errors in the ESP module though.
Do you think it's worth replacing this sensor, or is this potentially normal behaviour?
A few months ago I had an airmatic error for the front left harness on the strut. The mechanic re-seated the strut harness and ABS sensor. So I wonder if that is related?