Engine diagnostic indicator lamp on E320

[kustomtony]

My car is a 2001 petrol E320 Avant garde. I drove it to work this morning and all was fine, started it to come home at 4pm an the Engine diagnostic indicator lamp stayed on. when i got home i popped the bonnet and had a general fiddle, unplugged things and pluged them back in etc, then i noticed the washer bottle was low so i refilled that. i then started and all was fine with no light on, just test driven it and all seems to be good, no malfunctions on the display......so fingers crossed.
So what could that have been??????? is this a common fault???

 

[BlackC55]

There will be a fault code logged. You need to get it on a Star really

 

[Alan M]

The light coming on means that something was detected to be outside the normal working parameters. For example if there is a single misfire this will be noted by the ECU, but it may not generate a code or engine light until it has detected say 6 misfires. If you then switch the car off, and maybe it was a loose plug lead and you re seat it, when you restart the car the ECU will be monitoring and if there is no misfire it will turn the light off, but the code relating to it will be stored and reading this will give a clue as to why the light came on and help determine what repairs are required to prevent further problems.
Hope that helps explain things a little.
ps not saying your fault was leads or mis-fire - only the codes can tell you what it might be

 

[kustomtony]

Thanks mate, thats has explained it........all seems to be fine at the moment. gotta mate coming round over the weekend with a fault code reader, he reckons he can clear any logged faults.