CEL on and flashing low gaz light... now CEL still on

[MrSpace]

my low gaz light was flashing, I wen tout to check the gaz cap, it was fine..

then the light was off, rolled a little more, ti went on again with the CEL

now the low gaz light is ok, but the CEL still on

any clue?

I'm going to the dealer tomorrow, I just hope this is not due to my colder spark plugs or the new FPR

Etienne

[benzaddict]

When the check engine light comes on in conjunction with the fuel reserve light flashing it indicates an evap system leak, usually major(dtc p0455). With a minor evap leak(dtc p0442) the reserve light doesn't flash. If you checked the gas cap and it was tight, make sure the seal isn't leaking. A common place for leaks on W202's is the fuel expansion tank that sits in the right rear fender well. It incorporates the fuel filler neck and has several hoses attatched to it as it feeds into the main tank. Let us know what your dealer says, good luck.

[MrSpace]

thanks for the help, I have appointment for thursday morning

hope they have time to check it

Etienne

[sf280]

My car did that about a month ago because the cap was loose. It took about a week and then the CEL was magically off. You might want to wait a few more days to see if it goes off.

[ryhi]

i got the same problem today =( what was your outcome? is there supposed to be a release of air whenever u take off the gas cap after driving? i dont get the air releasing...

[ryhi]

what are other problems that might be causing the gas light to blink and CEL to come on?

[jnolte]

go to the gas station, fill er up and put on the cap tight.

If that dosent work then the seal on the cap may be faulty


if thats not the case its something more serious and you should have the stealer look at it

[ryhi]

do i have to fill up or can i just tighten it? i tightened it but the lights remain

[jnolte]

Originally posted by ryhi
do i have to fill up or can i just tighten it? i tightened it but the lights remain

no beacause there could be air in the system now. You need to filll it up to push it out. The car might think there is a leak. If you take off your gaz cap when ur not filling up your car, u can get a CEL sometimes.

[crazy00c230k]

i had that problem and it was something wrong w/one of the sensors in the fuel tank

[ryhi]

pulled the code today and i got P0455 Evaporative Emission Control System Leak Detected (Large)
mechanic said pressure isnt building or something. he said it could be a loose gas cap or a leak in one of the hoses

[martattack]

Could also be a fuel tank pressure sensor.

[REST_89]

I too have the same exact issue right now. I did find a leak near the purge valve ( the MOT Valve I think) It was located under the hood near the drivers headlight. I replaced the line since it was flat out tore in half, I have replaced the line and made sure the MOT valve was working properly. I reset the code and it was gone for a couple of hours, then it came back on.
However; before I found the leak, I replaced my gas cap with one from a junk yard.
unfortunately i still have the codes p0455 and p0170.

I pulled an older canister shut off valve from a c280 in a junk yard and was going to replace the one on my car to see if it would work, but the one I pulled looks really dirty. so I haven't done it yet.

I might just go get a new gas cap and reset the code and try again.. if that all fails, ill just go get the car smoke leak tested.. Im kind of a DIY kind of person but I cant figure this one out.. some people say its a fuel pressure sensor, others swear its the charcoal canister shut off valve...

[REST_89]

holy shit this is an old thread, Sorry mods.. I didn't mean to bump a thread from 10 years ago. :whoops:

[Denlasoul]

I would listen to benzaddict. He is a MB Master Mechanic and has worked on my car many times. Very knowledgeable and tries to find non-dealer solutions for the DIY'er.