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2005 E320 4-Matic Combi
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Discussion Starter #1
I have a model year 2000 E320 4-Matic sedan with 186,000 miles. The car runs great and recently passed the Illinois emissions test. Under certain conditions the low fuel warning light begins to flash and shortly afterward the check engine light also comes on. This occurs when the weather is warm and the fuel level is below roughly 1/2 tank. The light does not come on when the tank is full above 2/3 tank or when the weather is cold. The light comes on and flashes on warm days when the engine is at idle for several minutes. On a long drive at steady highway speed the light does not come on at all, even down to 1/8 tank and in even warm weather. When the weather is cold the light stays off under all conditions. I have replaced the gas cap but the problem still exists. I have been reading about similar symptoms resulting from a faulty purge valve on the evap canister. I would like to get opinions and recommendations from the forum on how to troubleshoot this problem.
 

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W210.265/2001, W220/S500/2000, Porsche 997 C2S/2006, GMC K1500/1992
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2,157 Posts
Sounds like you have bad contacts from the fuel sensor to the computer.
 

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2001 E320 - Brilliant Silver/Ash: 107,000+
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17,193 Posts
The flashing low fuel light has been discussed before but I don't remember the cause or solution. You might also try a search using "flashing fuel light" to see what pops up.
 

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1999 E300 TD
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2,045 Posts
I believe you have an issue with a ground. That ain't easy to trace with out wiring diagrams.

I would also have the car scanned via the OBD to determine if there is a solid fault----that may help with direction.

I know you won't like this but I would then get the car scanned via the 38 pin connector. That way you will really know what is going wrong!!

Failing that I would MOVE to a colder climate!!
 

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2001 SLK 320(217K Miles), 2002 E320 Special Edition(183K Miles)
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3,467 Posts
Isn't that leak at fuel cap?
When the new cap didn't solve it, I would check the rim for damages and check all the hose clamps.
But why would the fuel cap only leak when the tank is below half? The OP states it's not a problem when the tank is full.
 

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1990 Mercedes-Benz 420 SEL(RIP),1997 Mercedes-Benz E420
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1,936 Posts
I had the same problem and was able to fix it by reconnecting a hose that fell out of place connecting the "MOT" (located behind the windshield washer fluid) to the engine...Hope this helps.
 

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'02 E320 4matic Wagon
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326 Posts
It is probably only running the OBD test with less then full tank. I know when I had an issue on a Chrysler I own, the evap leak test was only run between 80% and 20% of tank capacity. There were a bunch of other temperature and drive cycle conditions too.
 

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2000 ML55 AMG
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50 Posts
Flashing Fuel Low + Check Engine Light

I know this is an old thread. I'm posting a reply for the benefit of other owners who will google it, just like I did.

2000 ML55, 128000 miles -- known "dead spot" in the fuel sender near full. When we refuel the vehicle, we get a "full" reading for about 25 miles, and then an indicated empty tank with a Low Fuel light on for another 25, and then the indicator goes back to 7/8 full. And it works normally all the way down. Sometimes, we get sporadic normal signals in the dead spot, notably when we go over bumps.

So we know the sender has problems.

Today I was stuck in traffic for half an hour behind an accident, creeping along, if moving at all, over new pavement for half an hour. Nearly through it I got the flashing Low Fuel and then Check Engine. I don't think we've ever run the car that long without moving. The tank is about 5/8 full. It came out of the dead spot two days ago.

Hypothesis: normal driving makes the fuel level sender bump around and move across spots on the wound wire sender that have too much corrosion to send a consistently good signal. A lot of sitting allowed the sender to settle on a bad spot for long enough for the computer to notice, and it threw the fault. I'll have one of our guys check the codes over lunch to verify.
 
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