W222 S350 EML & MAF

[flat6buster]

Have had local garage replace my MAF as EML was illuminated. EML came on day or two after they serviced it. They used a Bosch replacement MAF. Two days later EML came on again. They say it must for some reason be incompatible and we need to try an MB unit.

I am starting to doubt some of what they say for one reason and another. plugged in my ACME £9.99 code reader and it says P0111 error code which shows as Intake Air Temperature Sensor 1 Circuit/Range.

Question is would the intake air temperature sensor be part of the MAF? Or is it a separate part?

Is there a possibility they cocked something up at the service to make the EML come on?

I am just a bit weak in confidence with these guys and I don´t want to tunnel into a "throw parts at it" without asking the Sage Counsel of MB Club UK!

Thanks in avance.

 

[Supernoodle]

I don't know that engine, but everything else I've seen has a TMAF, ie includes the intake temp sensor. To be sure you can disconnect the MAF, if you get an error that says Air Temp Sensor 1 Open Circuit, that will confirm.

Why was MAF replaced in the first place?

 

[flat6buster]

Thank you. I guess that was the error code the garage read originally. Just seems of that Bosch make the mercedes part and they used a Bosch one yet it doesn't work. Oh well. Thank you for the help.

 

[Supernoodle]

If the original error was for the temp sensor too, I wouldn't just try another. Id be checking wiring, connectors and doing some checks first.

Temp sensors are effectively just resistors, they are easy to test and investigate and even simulate with a variable resistor.
Even your cheapo diag tool should be able to show the sensed air temp value too.

 

[flat6buster]

Thank you. That means turning the engine on with the diag tool in? Is that ok to do?

 

[Supernoodle]

Obsoletely, that's what they are designed for.

 

[flat6buster]

Thank you will post tomorrow!