CEL at full tank then clears at half tank
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CEL at full tank then clears at half tank
I've developed a CEL when filling up with gas. Oddly enough, the CEL clears by itself at half tank or so. Codes range from P0150 P0300 P0302 P0177.
This has happened on 2 tanks pf gas already
This has happened on 2 tanks pf gas already
Thread Starter
Junior Member
Joined: Nov 2005
Posts: 50
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I was thinking o2 sensors but why would it clear itself at half tank. Brought it to the dealer twice and they say most likely 02 sensors but couldn't understand why it clears itself when the fuel level goes down
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From: dfw
'10 C63
what year is your car?
i don't know much but i've got a 2010 and i've had to replace 2 o2 sensors after 6-7 years...
since your cel comes and goes with your fuel level, it may be possible that your gas cap isn't sealing up tightly when closed... maybe it needs replacing...
i don't know much but i've got a 2010 and i've had to replace 2 o2 sensors after 6-7 years...
since your cel comes and goes with your fuel level, it may be possible that your gas cap isn't sealing up tightly when closed... maybe it needs replacing...
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Joined: May 2016
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G63/RR LWB/W222 S550
I got my car back after some service last week and after filling up full tank had CEL. Took back to dealer who said o2 sensor and its been there since so I wonder whats up.
Hope they fix it because my warranty is about to end soon. 2013 48k miles
Hope they fix it because my warranty is about to end soon. 2013 48k miles
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From: dfw
'10 C63
i would also recommend clearing your codes afterward and monitor it for a while... if cel comes up again, check the codes and see if they are the same as before.
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2012 Mercedes C63 AMG S
There's another potential cause: overfilling of the fuel tank when pumping gas.
This happens on many cars (not just Mercedes). It is a result of excess gasoline flooding a vent system. This manifests on many vehicles as a trouble code. The trouble code would indeed go away after a portion of the overfilled tank has been consumed, as the vent system gets cleared of gas AND the trouble code is usually one that goes away after the ignition is cycled off.
Overfilling can sometimes be "non-obvious":
- Pump shutoff is incorrectly set or too slow
- Pump delivery rate is set high so even a timely shutoff keeps the fuel flowing a bit too long
- Car is not level because front or rear axle is "off the concrete pad" that surrounds the pumps in an otherwise paved lot and so is lower
- Owner does not realize that you MUST stop pumping when the pump clicks off, not try for the next "even dollar amount"
- Some vehicles are also just too sensitive as a result of stacked manufacturing tolerances or marginal sensors
Try stopping the fuel flow a little early and see if the problem goes away.
Jim G
This happens on many cars (not just Mercedes). It is a result of excess gasoline flooding a vent system. This manifests on many vehicles as a trouble code. The trouble code would indeed go away after a portion of the overfilled tank has been consumed, as the vent system gets cleared of gas AND the trouble code is usually one that goes away after the ignition is cycled off.
Overfilling can sometimes be "non-obvious":
- Pump shutoff is incorrectly set or too slow
- Pump delivery rate is set high so even a timely shutoff keeps the fuel flowing a bit too long
- Car is not level because front or rear axle is "off the concrete pad" that surrounds the pumps in an otherwise paved lot and so is lower
- Owner does not realize that you MUST stop pumping when the pump clicks off, not try for the next "even dollar amount"
- Some vehicles are also just too sensitive as a result of stacked manufacturing tolerances or marginal sensors
Try stopping the fuel flow a little early and see if the problem goes away.
Jim G
MBWorld Fanatic!
Joined: May 2008
Posts: 1,601
Likes: 14
From: dfw
'10 C63
There's another potential cause: overfilling of the fuel tank when pumping gas.
This happens on many cars (not just Mercedes). It is a result of excess gasoline flooding a vent system. This manifests on many vehicles as a trouble code. The trouble code would indeed go away after a portion of the overfilled tank has been consumed, as the vent system gets cleared of gas AND the trouble code is usually one that goes away after the ignition is cycled off.
Overfilling can sometimes be "non-obvious":
- Pump shutoff is incorrectly set or too slow
- Pump delivery rate is set high so even a timely shutoff keeps the fuel flowing a bit too long
- Car is not level because front or rear axle is "off the concrete pad" that surrounds the pumps in an otherwise paved lot and so is lower
- Owner does not realize that you MUST stop pumping when the pump clicks off, not try for the next "even dollar amount"
- Some vehicles are also just too sensitive as a result of stacked manufacturing tolerances or marginal sensors
Try stopping the fuel flow a little early and see if the problem goes away.
Jim G
This happens on many cars (not just Mercedes). It is a result of excess gasoline flooding a vent system. This manifests on many vehicles as a trouble code. The trouble code would indeed go away after a portion of the overfilled tank has been consumed, as the vent system gets cleared of gas AND the trouble code is usually one that goes away after the ignition is cycled off.
Overfilling can sometimes be "non-obvious":
- Pump shutoff is incorrectly set or too slow
- Pump delivery rate is set high so even a timely shutoff keeps the fuel flowing a bit too long
- Car is not level because front or rear axle is "off the concrete pad" that surrounds the pumps in an otherwise paved lot and so is lower
- Owner does not realize that you MUST stop pumping when the pump clicks off, not try for the next "even dollar amount"
- Some vehicles are also just too sensitive as a result of stacked manufacturing tolerances or marginal sensors
Try stopping the fuel flow a little early and see if the problem goes away.
Jim G
