kpg0628

I received the famous flashing gas pump icon and bright red Check gas cap message on my 2006 E-500 with 113,000 miles that I purchased in January of this year. After a few weeks of intermittent and regular occurrence, a check engine light (P0455) was added to the mix. I've spend the past 4 weeks trying to troubleshoot and fix the issue unsuccessfully. Here is a list of my attempts:

NOTE: All parts replaced were genuine MB
1. Replaced the gas cap
2. Replaced the purge valve.
3. Smoke tested the hose from the purge valve to the intake. No leaks detected.
4. Tested/probed the new purge valve to ensure it's opening when activated and seals securely when closed. Tested the old one which also seemed fine.
5. Smoked tested the hose from the purge valve to the canister (used a balloon to seal the canister vent). No leaks detected.
6. Tested/probed the canister shutoff valve. Closes and seals securely when probed.
7. Replaced the canister shutoff valve (even though old one seemed fine). Problem remained so replaced with the old one.
8. Examined overflow hose connected to canister and no observed issues
9. Removed canister and put it in a cool/dry place for a few days. Shook the canister and verified that charcoal was not tarred up.
10. Replaced the fuel tank pressure sensor this past weekend. I was able to drive the car for about 150 miles with no issues. This morning on my way to work I received the blinking gas pump icon + Check gas cap message followed by a CEL (P0455).

Could it be a faulty fuel sending unit assembly? Is there a way to test/verify this?

Pmarino

Did you recently have the pump or filter changed? Did you replace the pressure sensor with a OEM sensor? Did you also replace the damper cage?
There are 2 notorious hose connections to check; check out https://mbworld.org/forums/w211-amg/709510-p0455-woes.html
Evaporative fuel system hard line into supercharger grommet.

kpg0628

No changes to the pump or filter. I was pretty confident the issue was with the fuel tank pressure sensor. I replaced it with an OEM sensor but it didn't resolve the issue. I decided to return the sensor and exchange it for a new one. So far the replacement sensor is looking good. I'll give it another few days before I declare victory and will update this post.

Pmarino

Sounds intermittent, I would check the connector and wires.

kpg0628

After trying another fuel tank pressure sensor, I was able to drive the vehicle for 1/2 a tank (2-3 days) with no issues. I thought I had the issue resolved but not its back. I've checked the hose connections and wires several times. Only thing I haven't checked is the fuel pump which I will do next.
If all looks good with the fuel pump housing and seals, I'll be heading to the stealer for analysis.

Laude

any updates?

Maj. Dundee

Laud, you are on the wrong forum.