W208 No 5V power to MAF - PLEASE HELP

[ClayDog]

Hi to all of those with superior wisdom than I!

I have a '01 CLK 230. The management light has been on and garage have tried everything from replacing breather hozes to valve solenoids and eventually today the MAF sensor - with no luck!

Now they have said there is no 5 volt supply to the MAF sensor (apparently pin 48 on the ECU). They want to change the ECU (And wiring loom because of POSSIBLE oil ingress!! )

PLEASE can someone advise on whether they think it's the ECU. Should pin 48 have 5 volts on it, and if it is just the 5V supply voltage that is missing, can I daisy-chain the 5 volts from another sensor or control unit to test it?

Thanks

 

[Cole@MBS]

welcome claydog

Yes pin 48 should see 5 volts, my main concern is that model is prone to oil in-gress from the cam sensor, then yes, new loom etc needed!

 

[BlackC55]

You are one of many......

 

[Cole@MBS]

Just to add, the ECU can be washed out, done a few now!

 

[Cole@MBS]

Evening olly! your on here late!

 

[BlackC55]

Just leaving work now.

Trying to fix that poxy a-class.

I think the MSM is fried. Only £1100!

What a week.

 

[Cole@MBS]

Just leaving work now.

Trying to fix that poxy a-class.

I think the MSM is fried. Only £1100!

What a week.

Tell me about it mate!!!!

 

[television]

I used to have good weeks and bad weeks,, now I just have weeks that are all the same

 

[ClayDog]

Hey Sam thanks for the reply

Cam sensor has already had a mod connector on it. Really no sign of oil ingress to me!

So do you reckon a new ECU is needed if I can't get 5 volts off that pin? Reckon it's worth trying to nab 5 volts off one of the other 5 volt supplies? The sensing part of the circuit seems to be working, as the engine chases for revs when you start her, until it takes the default setting.

I'll give it a go to wash the ECU out. You just use electronic cleaner?

Ciao

 

[Cole@MBS]

Nicking 5 volts from some other place will throw up more codes, it all done by resistance, the ecu will detect that fact!

 

[television]

I will take a look at the circuit.

The PCB in the ECU could have an open circuit track

 

[television]

What I would do here is to apply a 5volt from an external source, this is standard practice for me and see what happens