Service Fuel System
06-26-2010, 11:05 AM
#1
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Service Fuel System
Okay, I think I did a bad thing. I filled up my car (2009 C6) while it was running. All went fine until the fuel gauge went to zero an the troublesome Service Fuel System appeared on the DIC. I drove the car a few miles and the warning is still there and the gauge reads 0.
Did this cause the Fuel sending unit to go bad like I've read in other posts? Can I simply reset the system some way or do I have to go to the dealer to have it looked at?
Any ideas out there......
Did this cause the Fuel sending unit to go bad like I've read in other posts? Can I simply reset the system some way or do I have to go to the dealer to have it looked at?
Any ideas out there......
06-26-2010, 12:46 PM
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St. Jude Donor '13
Unfortunately, this problem can not be fixed. Ship you car to me and I will dispose of it properly.
Seriously, if the problem was caused by your filling technique, I'm told it can take several start/run/shutdown cycles, to clear the message. Or find a dealer, or a person or store with a code reader that can clear the code immediately.
Let us know...
Seriously, if the problem was caused by your filling technique, I'm told it can take several start/run/shutdown cycles, to clear the message. Or find a dealer, or a person or store with a code reader that can clear the code immediately.
Let us know...
06-26-2010, 12:52 PM
#4
Melting Slicks
You just need to clear the code. You may be able to do this by disconnecting the battery, but Autozone will do it for free.
Short explination, the C6 has two fuel sending units, one in each tank. If one reads over .5 volts different than the other it sends your gauge to zero. There's other reasons to fill your car while it's off, but this one is particular to the C6.
Short explination, the C6 has two fuel sending units, one in each tank. If one reads over .5 volts different than the other it sends your gauge to zero. There's other reasons to fill your car while it's off, but this one is particular to the C6.
06-26-2010, 01:02 PM
#5
Melting Slicks
You just need to clear the code. You may be able to do this by disconnecting the battery, but Autozone will do it for free.
Short explination, the C6 has two fuel sending units, one in each tank. If one reads over .5 volts different than the other it sends your gauge to zero. There's other reasons to fill your car while it's off, but this one is particular to the C6.
Short explination, the C6 has two fuel sending units, one in each tank. If one reads over .5 volts different than the other it sends your gauge to zero. There's other reasons to fill your car while it's off, but this one is particular to the C6.
06-26-2010, 01:14 PM
#6
Melting Slicks
With my custom fuel system I fought the damn thing several times and that's what I have so far.
06-27-2010, 02:18 PM
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Well, I drove the car more today and I still have that annoying Service Fuel System Warning & Fuel gauge still reads 0. Tried topping up the fuel again and no success. Stopped by local auto parts shop (hate having parts store "people" muck with the computer but dude said he could not reset computer with his tool).
Anyways, looks like I may have to make the dreaded trip to the dealer. Probably not a major issue if they can reset the system. Otherwise they may have to drop the tanks and change Fuel Sending Unit(s). Keeping my fingers crossed, hoping for a minimally invasive procedure. (only 4800 miles on the car)
WE shall see.....
Anyways, looks like I may have to make the dreaded trip to the dealer. Probably not a major issue if they can reset the system. Otherwise they may have to drop the tanks and change Fuel Sending Unit(s). Keeping my fingers crossed, hoping for a minimally invasive procedure. (only 4800 miles on the car)
WE shall see.....
06-27-2010, 02:48 PM
#8
Team Owner
You can try disconnecting the battery for 5 minutes and then reconnecting . . .you may need to re-index the windows - -see manual- or just put them up, release and then hold the switch up for 5 sec . .
That may clear the code and the problem . . if not, yes - -you're gonna need to visit the dealer.
That may clear the code and the problem . . if not, yes - -you're gonna need to visit the dealer.
06-27-2010, 03:19 PM
#9
Melting Slicks
I predict the day you get in to drive it to the dealer the gauge starts working 
I was looking through the shop manual and it actually does say that some codes regarding the fuel system can indeed be set by refueling with the engine on. There are several checks the car is doing to verify everything is working since we have 2 fuel level senders. It does things like make sure if sender 1 (right) says it's at 0, then withing 30 minutes/100 miles (don't quote me on those) it needs to see a change in sender 2's (left) level, or if it sees sender 1 at full but sender 2 is reading low something is wrong. I can see how refueling with the car running can get things messed up, but I would also think that within a few trips the thing would sort itself out.
I was looking through the shop manual and it actually does say that some codes regarding the fuel system can indeed be set by refueling with the engine on. There are several checks the car is doing to verify everything is working since we have 2 fuel level senders. It does things like make sure if sender 1 (right) says it's at 0, then withing 30 minutes/100 miles (don't quote me on those) it needs to see a change in sender 2's (left) level, or if it sees sender 1 at full but sender 2 is reading low something is wrong. I can see how refueling with the car running can get things messed up, but I would also think that within a few trips the thing would sort itself out.
06-27-2010, 03:29 PM
#10
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Probably has nothing to do with the fuel level sensors. Here is a description of how the Evap system works. When you had the tank open with the engine running you interrupted the vacuum/pressure integrity of the fuel system.
Evaporative Emission Control System Description
EVAP System Operation
The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.
Large Leak Test
This tests for large leaks and restrictions to the purge path in the evaporative emission (EVAP) system. When the enabling criteria has been met, the control module commands the EVAP vent solenoid valve ON and the EVAP purge solenoid valve ON, allowing vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. DTC 0455 will be set.
Small Leak Test
The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.
The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.
The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.
Canister Vent Restriction Test
If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.
Purge Solenoid Valve Leak Test
If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.
Check Gas Cap Message
The control module sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when a malfunction in the evaporative emission (EVAP) system and a large leak test fails.
EVAP System Components
The evaporative emission (EVAP) system consists of the following components:
EVAP Canister
The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.
EVAP Purge Solenoid Valve
The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.
EVAP Vent Solenoid Valve
The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.
Fuel Tank Pressure Sensor
The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.
The referenced DTCs are Type B DTCs. Here is what that means:
Action Taken When the DTC Sets - Type B
• The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC - Type A or Type B
• The control module turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.
Bill
Evaporative Emission Control System Description
EVAP System Operation
The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid valve to the atmosphere. The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid valve ON, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid valve OFF, fresh air is drawn through the vent solenoid valve and the vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid valve into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.
Large Leak Test
This tests for large leaks and restrictions to the purge path in the evaporative emission (EVAP) system. When the enabling criteria has been met, the control module commands the EVAP vent solenoid valve ON and the EVAP purge solenoid valve ON, allowing vacuum into the EVAP system. The control module monitors the fuel tank pressure (FTP) sensor voltage to verify that the system is able to reach a predetermined level of vacuum within a set amount of time. DTC 0455 will be set.
Small Leak Test
The engine off natural vacuum (EONV) diagnostic is the small-leak detection diagnostic for the evaporative emission (EVAP) system. While previous leak detection methods were performed with the engine running, the EONV diagnostic monitors the EVAP system pressure or vacuum with the ignition OFF. Because of this, it may be normal for the control module to remain active for up to 40 minutes after the ignition is turned OFF. This is important to remember when performing a parasitic draw test on vehicles equipped with EONV.
The EONV utilizes the temperature changes in the fuel tank immediately following a drive cycle to use the naturally occurring vacuum or pressure in the fuel tank. When the vehicle is driven, the temperature rises in the tank. After the vehicle is parked, the temperature in the tank continues to rise for a period of time, then starts to drop. The EONV diagnostic relies on this temperature change and the corresponding pressure change in a sealed system, to determine if an EVAP system leak is present.
The EONV diagnostic is designed to detect leaks as small as 0.51 mm (0.020 in). The diagnostic can determine if a small leak is present based on vacuum or pressure readings in the EVAP system. When the system is sealed, a finite amount of pressure or vacuum will be observed. When a 0.51 mm (0.020 in) leak is present, often little or no pressure or vacuum is observed. If the test reports a failing value, DTC P0442 will set.
Canister Vent Restriction Test
If the evaporative emission (EVAP) vent system is restricted, fuel vapors will not be properly purged from the EVAP canister. The control module tests this by commanding the EVAP purge solenoid valve ON, commanding the EVAP vent solenoid valve OFF, and monitoring the fuel tank pressure (FTP) sensor for an increase in vacuum. If the vacuum increases more than a calibrated value, DTC P0446 will set.
Purge Solenoid Valve Leak Test
If the evaporative emission (EVAP) purge solenoid valve does not seal properly fuel vapors could enter the engine at an undesired time, causing driveability concerns. The control module tests for this by commanding the EVAP purge solenoid valve OFF and the vent solenoid valve ON, sealing the system, and monitors the fuel tank pressure (FTP) for an increase in vacuum. If the control module detects that the EVAP system vacuum increases above a calibrated value, DTC P0496 will set.
Check Gas Cap Message
The control module sends a class 2 message to the driver information center (DIC) illuminating the Check Gas Cap message when a malfunction in the evaporative emission (EVAP) system and a large leak test fails.
EVAP System Components
The evaporative emission (EVAP) system consists of the following components:
EVAP Canister
The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.
EVAP Purge Solenoid Valve
The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. The purge solenoid valve opens when commanded ON by the control module. This normally closed valve is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The valve will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.
EVAP Vent Solenoid Valve
The EVAP vent solenoid valve controls fresh airflow into the EVAP canister. The valve is normally open. The control module commands the valve ON, closing the valve during some EVAP tests, allowing the system to be tested for leaks.
Fuel Tank Pressure Sensor
The fuel tank pressure (FTP) sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. A high FTP sensor voltage indicates a low fuel tank pressure or vacuum. A low FTP sensor voltage indicates a high fuel tank pressure.
The referenced DTCs are Type B DTCs. Here is what that means:
Action Taken When the DTC Sets - Type B
• The control module illuminates the MIL on the second consecutive ignition cycle that the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC - Type A or Type B
• The control module turns OFF the MIL after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.
Bill
06-27-2010, 03:53 PM
#11
Melting Slicks
That is good info, but the EVAP system and it setting DTCs have nothing to do with driving the fuel gauge, which is reading zero. For instance, leaving the gas cap off will set a code for this system, gauge still works.
06-27-2010, 05:33 PM
#12
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Thanks for all of the good information. I did disconnect the battery yesterday and it did not fix it. But that was only like for a minute or two, since I'm an impatient person. Well Today I tried again, but this time I let it sit for like 20 minutes disconnected while I putzed around on the internet.
So long story short.... IT'S FIXED now. Needed to disconnect battery for longer period than I first tried. Now all is well again. Lesson learned, don't refuel car while it is running. It makes her unhappy.....
THANKS ALL!!
So long story short.... IT'S FIXED now. Needed to disconnect battery for longer period than I first tried. Now all is well again. Lesson learned, don't refuel car while it is running. It makes her unhappy.....
THANKS ALL!!
