So the saga continues,
I've replaced:

1. EGR Valve
2. Fuel cap
3. Air Mass ( For the F**k of it, don't ask why )

Bosch service centre tells me it could be the fuel guage and pressure sensor ( obsolete )
They also said the vaccuum hose needs to be replaced which they haven't ( I have no idea why )


Anyways, anyone know the part number or wher I can source the fuel presure sensor?

1999 SL500

Thanks in advance.

 

The EGR valve has nothing to do with the EVAP system, so that part change is as much a puzzle as the air mass sensor replacement.

If I were going to continue playing Parts Roulette in lieu of actual diagnostic work -- something I personally would not do -- I would focus on the vacuum line attachment points and ignore the fuel tank pressure sensor. Note that the sensor is not a fuel pressure sensor, since it measures vacuum within the fuel tank.

You might go to the "Tech Help" forum at peachparts.com and do a search. Years ago that forum had no fewer than four professional Mercedes techs participating on a regular basis. I expect you will find EVAP system leaks have been discussed many times and may get a better idea where to place your next Parts Roulette bet.

 

Thank you Bob

I am anxiously awaiting for the CEL light to come back on, it's been quiet for the last few days.

 

Just wondering if you ever got this sorted out and how? I have a 98 same issues. Replaced cap, purge valve, gas tank sending unit, ran smoke test and replaced hose under front fender, still get CEL and 0445 code.

 

I had that on my 94 SL320 and it turned out to be charcoal canister letting bits get stuck in purge valve I cleaned it out and tested that it did seal I put an inline fuel filter in the hose coming from the canister never got code again

 

Yes, it was a bad hose and also my gas cap had to be replaced again as the one purchased from the dealer was the wrong one.