SL/R230: Fuel gauge showing low fuel but full tank?
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Senior Member
Joined: Apr 2007
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Former R230, W220 and W221 owner
Fuel gauge showing low fuel but full tank?
2003 SL500
started the car this morning and it stated I’m low on fuel. I know that’s false because I had a half a tank yesterday. This has happened two or three times now where the fuel gauge would show that I have no fuel but then after 10/15 minutes of driving or shutting the car on and off, the gauge moves to the correct position
car drives and starts fine
help?
started the car this morning and it stated I’m low on fuel. I know that’s false because I had a half a tank yesterday. This has happened two or three times now where the fuel gauge would show that I have no fuel but then after 10/15 minutes of driving or shutting the car on and off, the gauge moves to the correct position
car drives and starts fine
help?
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From: Gretna, NE
'03 SL55 Black, '03 SL500's Aegean, Mars Red, Tazanite, Alabaster, '11 S550 Flint Gray
Probably either a sender going bad or bad communication with the rear SAM. The tank level is read by the rear SAM and then sent to the cluster via CAN message. I believe that the cluster defaults to empty tank if it doesn't get updates. If you have access to a scan tool, check for codes and check the fuel level actual value in the rear SAM.
Thread Starter
Senior Member
Joined: Apr 2007
Posts: 435
Likes: 79
Former R230, W220 and W221 owner
Probably either a sender going bad or bad communication with the rear SAM. The tank level is read by the rear SAM and then sent to the cluster via CAN message. I believe that the cluster defaults to empty tank if it doesn't get updates. If you have access to a scan tool, check for codes and check the fuel level actual value in the rear SAM.
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Joined: Dec 2019
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From: Houston, TX
2005 SL600
If there are no helpful codes or data, something else to check - the R230 has a known problem where a baffle inside the gas tank breaks loose. The usual symptom reported is that you hear it clunking against the side of the gas tank. I've never seen it reported that it caused a problem with the fuel level sensor, but it seems like it could if the loose baffle prevented the float from operating properly.
Thread Starter
Senior Member
Joined: Apr 2007
Posts: 435
Likes: 79
Former R230, W220 and W221 owner
If there are no helpful codes or data, something else to check - the R230 has a known problem where a baffle inside the gas tank breaks loose. The usual symptom reported is that you hear it clunking against the side of the gas tank. I've never seen it reported that it caused a problem with the fuel level sensor, but it seems like it could if the loose baffle prevented the float from operating properly.
Looks like the sender is in the trunk and somewhat easy to replace
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2017 GLC 300 Mercedes Benz
Probably either a sender going bad or bad communication with the rear SAM. The tank level is read by the rear SAM and then sent to the cluster via CAN message. I believe that the cluster defaults to empty tank if it doesn't get updates. If you have access to a scan tool, check for codes and check the fuel level actual value in the rear SAM.
s
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Joined: Aug 2020
Posts: 1,326
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From: Gretna, NE
'03 SL55 Black, '03 SL500's Aegean, Mars Red, Tazanite, Alabaster, '11 S550 Flint Gray
In your case, the fuel level is read by the fuel pump control module. If there are level sensor codes in that module, I would start with Option 1 or 2. The reason that they gave you two options is while the sensor is available from Mercedes, an entire aftermarket fuel pump assembly is cheaper and quicker to replace. There is also a chance that the wiring between the sender and pump control is faulty, or the control is faulty. This is whey they have option 4, in case they need to check wiring, etc.
If you have no codes in the fuel pump module and the module has a fuel quantity that can be read on diagnostics, you might have an issue with the cluster or CAN (network) issues. This would be harder to diagnose and more expensive to fix, but it is the less likely case.
Note: The quoted labor rates are very reasonable, parts markup is 100% or higher.
If you have no codes in the fuel pump module and the module has a fuel quantity that can be read on diagnostics, you might have an issue with the cluster or CAN (network) issues. This would be harder to diagnose and more expensive to fix, but it is the less likely case.
Note: The quoted labor rates are very reasonable, parts markup is 100% or higher.
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2017 GLC 300 Mercedes Benz
In your case, the fuel level is read by the fuel pump control module. If there are level sensor codes in that module, I would start with Option 1 or 2. The reason that they gave you two options is while the sensor is available from Mercedes, an entire aftermarket fuel pump assembly is cheaper and quicker to replace. There is also a chance that the wiring between the sender and pump control is faulty, or the control is faulty. This is whey they have option 4, in case they need to check wiring, etc.
If you have no codes in the fuel pump module and the module has a fuel quantity that can be read on diagnostics, you might have an issue with the cluster or CAN (network) issues. This would be harder to diagnose and more expensive to fix, but it is the less likely case.
Note: The quoted labor rates are very reasonable, parts markup is 100% or higher.
If you have no codes in the fuel pump module and the module has a fuel quantity that can be read on diagnostics, you might have an issue with the cluster or CAN (network) issues. This would be harder to diagnose and more expensive to fix, but it is the less likely case.
Note: The quoted labor rates are very reasonable, parts markup is 100% or higher.
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2017 GLC 300 Mercedes Benz
