What do I do if the Check Fuel Cap message appears?

What do I do if the Check Fuel Cap message appears?
Experienced mechanics share their insights in answering this question :
Your car is equipped with a pretty sophisticated evap/emissions system that monitors the level of pressure in the gas tank. This is done to detect possible leaks, including a loose gas cap. If you’ve left the cap loose (or off), the Check Fuel Cap message will show up on your dash. To handle the situation, follow these steps:

Turn off the engine.
Open the fuel door.
Double check the gas cap and tighten if necessary.
Crank the car and drive normally.
The light should go off within a few days. If it doesn’t, the code will need to be checked.

Tips

If the light doesn’t go off, it could mean there is a leak in your system, or the cap is bad.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Simply put, if your fuel cap light is on, it means that the computer has detected a leak in the system, typically from a loose gas cap. If this light comes on while driving, pull over in a safe spot and re-secure the cap. Continue driving normally with the light illuminated and it should go off within a day or two.
“Check fuel cap” can be a warning message that appears on several makes of vehicles. But what does this seemingly simple message mean? The Check Fuel Cap warning light denotes that your fuel cap isn`t correctly installed on the car. Or is damaged, even missing from the fuel tank filler tube altogether.
The check engine light should go off after you drive for several minutes if the light was caused by a loose gas cap. Pay attention to the dashboard after the check engine light experience. If you find that the light keeps coming on, and goes off again once you tighten the gas cap, then your gas cap is too loose.
A check fuel cap indicator indicates the ECM detected a pressure leak in your Accord`s fuel tank. Several common reasons for this problem include a missing fuel cap, a tightened cap that is not tight enough, or a damaged cap.
The average cost for a Gas Cap Replacement is between $92 and $97. Labor costs are estimated between $18 and $22 while parts are priced between $74 and $75.
Depending on the caliber of your car, a new gas cap can cost anywhere from $100 to around $300.
The fuel tank pressure sensor is part of the fuel pump assembly and is mounted on top of the tank or inside the tank. It`s part of the evaporative emissions system (commonly referred to as “EVAP”) and reads pressure in the fuel system to detect evaporative leaks, such as a loose or faulty gas cap.
A non-secure gas cap will not only let in dirt and grime, but it can allow fuel vapors to escape. These fuel vapors can produce an error in the emissions system, which could light up the check engine light. Dirt and Grime that seeps into the fuel tank can also contaminate the injectors over time.
Press and hold the “Trip/Odo” button again until the Odometer says “1.” This means that the reset process has begun. Keep holding the button down while the fuel gauge resets. Release the “Trip/Odo” button once the reset is complete. You`ll know the process is finished when the Odometer display moves back to normal.
In most cases, successfully repairing the issue that caused your light to come on will cause the check engine light to turn off automatically—but only after 10 to 20 “cycles”.
It takes 3 separate steps to get your fuel system really clean. (We do all three). Clean the gas pump, fuel lines and injectors by adding cleaner to the gas and running the engine. Add a second cleaner directly to the warm engine to remove gunk and carbon deposits from the combustion chambers.
In most cases, successfully repairing the issue that caused your light to come on will cause the check engine light to turn off automatically—but only after 10 to 20 “cycles”.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

What do I do if the Check Fuel Cap message appears?
ANSWER : Your car is equipped with a pretty sophisticated evap/emissions system that monitors the level of pressure in the gas tank. This is done to detect possible leaks, including a loose gas cap. If you’ve left the cap loose (or off), the Check Fuel Cap message will show up on your dash. To handle the situation, follow these steps:

Turn off the engine.
Open the fuel door.
Double check the gas cap and tighten if necessary.
Crank the car and drive normally.
The light should go off within a few days. If it doesn’t, the code will need to be checked.

Tips

If the light doesn’t go off, it could mean there is a leak in your system, or the cap is bad.

Evaporative Emission Control System Leak Detected (Gross leak, check fuel cap, piping etc): Code P0455
ANSWER : Hello, thank you for writing in. The vehicle is experiencing a leak either with the EVAP system, or pertaining to the fuel tank. A visual inspection of the fuel tank and filler neck can rule out any physical damage in that area. You may also have to perform and evaporative emissions leak test. This will tell you where the leak is coming from, and you can take further diagnosis or repairs from there. You may want to pay special attention to the purge valve and do some further inspection on it as well. For more help, contact our service department to schedule an appointment.

I have a 1981 e-350 with dual fuel tanks the p.o. added a third tank and 3 electric fuel pumps along with sepparate gauges and swi
ANSWER : The switch you are referring to is vended with the required electrical and fuel schematic (I just looked in the box) that answers your installation question. If you want an advance view, here is a link as well. Yes, you need a return line and just refer to the aforementioned link. If you are retrofitting back to OEM, I strongly encourage you to buy the original Factory Service Manual (FSM). There are lots of details attending this system and obviously it is difficult to recount it all here. The FSM will make your life much easier and you can then make sure your installation is perfect. Alternatively, YourMechanic can dispatch a certified mechanic and perform the whole retrofit and check out if you desire. Just request and schedule a generic service such as fuel pump service and the mechanic will come to your location and estimate the parts and labor required. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Car is not getting fuel. I changed fuel pump and checked the fuel pump relay. It was in good condition. What else could it be?
ANSWER : This may likely be related to the fuel pressure regulator. This is a unit that helps to maintain the fuel pressure in the system. When this is not working, this may cause an erratic fluctuation in the fuel pressure or in some cases, no fuel pressure at all. If you’d like assistance with this repair, I would recommend having an expert from YourMechanic come to your location to diagnose the issue firsthand and service your fuel pressure regulator as necessary.

Just replaced my fuel pump but its not getting any power tested fuel pump relay and fuel fuse both good tested the wires all good.
ANSWER : You need to look at the theft light on dash to make sure it comes on and goes off when you turn the key to the on position. If light comes on and stays on then your theft system is causing the fuel pump to not be engaged. I recommend you check the theft system and then scan the computer for theft system codes. You may need to reprogram the keys to work or you have an bad sensor for the ignition key in the steering column.

2014 Toyota Corolla Fuel Odor
ANSWER : This may be related to the fuel tank purging system. As you may know, all modern cars are equipped with an Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the charcoal canister. The charcoal canister is filled with activated carbon pellets that can absorb the fuel vapors. When the engine is running, the fuel vapors are purged from the canister and burned in the engine. The vent control valve (solenoid) controls the flow of outside air in and out of the charcoal canister. When this solenoid is not working properly, this will cause excess pressure to back up into the tank resulting in the fuel cap being the path of least resistance. This may be what is causing it to back out on you. If you would like to have an expert check this out, a certified technician from YourMechanic can come to your car’s location to inspect the fuel system for you and advising on a repair.

Check engine light
ANSWER : Hi and thanks for contacting YourMechanic. From what you’ve described, it seems that the mechanic was doing a good job. If your injectors were replaced, the fuel pump was replaced, and the fuel system was flushed out the system should be good from the bad gas.

However, the question to ask is how was the fuel system flushed. So, what you could do is remove the fuel line to the fuel injection system. Hook up a hose to the line and put it into a gas can. Then find the fuel pump relay and remove it. Grab a jumper wire and bridge the terminals on the relay ports on the fuse box and make the pump come on. Turn the key on and pump all of the fuel out. Turn the key off and put in new fuel. Turn on the key again and pump the fuel out again. This will insure that all of the fuel is clean in your vehicle.

Then remove the jumper wire and put the relay back in the ports. Turn on the key with new fuel in the fuel tank and pressurize the system. Remove the battery ground and clear the codes. Hook up the battery and test drive the vehicle for about a week. If the light does not come on, then you still had bad gas in the lines. If the light comes back on, then have the light checked for what the codes are.

Sometimes the gasket on the fuel filler neck to the fuel cap could be damaged or the neck itself could be damaged making the vapor sensor pick up a gross leak. I recommend replacing the fuel fuller cap gasket to the gas cap and retest the system before flushing the system out. Also, I recommend looking at the vapor lines under the vehicle for any cracks and replace them if they are cracked.

If you need assistance in troubleshooting your fuel issue or would like a fresh pair of eyes on the issue, consider YourMechanic, as one of our mobile technicians can come to you and properly diagnose your Check Engine Light firsthand.

How long and what is the process to replace a fuel pressure sensor?
ANSWER : A professional mechanic would require roughly 5 hours. (If just the regulator is replaced that takes about 1 hour). Some parts, as noted below, cannot be re-used, you need a precision inch pound torque wrench, FSM instructions (and TSB updates if applicable; procedure was changed in 2007 for instance) and the system has to be bled when done.

Below is partial list of steps, copied and pasted directly from the service manual:

1. Disconnect battery and put protective material in front of the charge air cooler (CAC) or damage to the CAC may occur.

2. Remove air cleaner assembly.

3. Disconnect the oil drain tube from the crankcase vent oil separator.

4. Loosen the air cleaner outlet tube clamp and detach the air cleaner outlet tube from the turbocharger.

5. Remove the bolts, the crankcase vent oil separator and the air cleaner outlet pipe as an assembly.

6. Remove and discard the crankcase vent oil separator press-in-place gasket. (To re-install, tighten to 13 Nm (115 lb-in).

7. Disconnect the PCM electrical connector (BE SURE BATTERY IS DISCONNECTED FIRST!) and retainer. Disconnect the in-line electrical connector and position the engine wiring harness on the engine.

8. Remove the pushnuts and the glow plug module heat shield.

9. Disconnect the high-pressure fuel injection pump electrical connector and detach the retainer from the glow plug module bracket. Disconnect the glow plug module and the exhaust gas recirculation temperature (EGRT) sensor electrical connectors, detach the wiring retainer and position the wiring harnesses aside.

10. Remove the nut and position the ground strap aside. To install, tighten to 13 Nm (115 lb-in).

11. Remove the engine wiring harness bolt. To install, tighten to 13 Nm (115 lb-in).

12. Remove the heater supply tube nut. To install, tighten to 13 Nm (115 lb-in).

13. Remove the bolts and the glow plug module bracket. To install, tighten to 13 Nm (115 lb-in).

14. Remove the nut and position the transmission fluid indicator tube aside. To install, tighten to 8 Nm (71 lb-in).

Warning: Do NOT disconnect the glow plug electrical connector before dislodging the seal from the valve cover or the wiring harness may be damaged.

15. Using an appropriate tool, dislodge the glow plug wiring harness seals from the valve cover.

16. Disconnect the glow plug electrical connectors by pulling on the glow plug wiring harness tee above the seal. Remove the glow plug wiring harness.

17. Remove the nut and position the crankcase ventilation drain tube aside.

18. Disconnect the wiring harness retainer from the valve cover stud.

19. Disconnect the wiring harness retainer from the generator bracket.

20. Disconnect the A/C pressure switch electrical connector. Position the harness aside.

Warning: Do not bend or flex the heater supply tube or damage to the tube may occur.

21. Remove the stud bolts, bolts and the valve cover. Remove and discard the valve cover gasket. To install, tighten to 9 Nm (80 lb-in).

Warning: Contact with exposed fuel injector wiring, if energized, may result in electric shock.

Use care when working on or around energized fuel injector wiring. Fuel injector wiring supplies HIGH VOLTAGE to operate the fuel injectors of course, you disconnected the battery though.

22. Disconnect the fuel rail pressure (FRP) sensor electrical connector.

Warning: Fuel injection equipment is manufactured to VERY precise tolerances and fine clearances (think space shuttle). To prevent fuel system damage, it is essential that absolute cleanliness is observed when working with these components. Always install fuel system caps on any open orifices or tubes.

23. Remove the FRP sensor. To install, tighten the FRP sensor in 2 stages.

Stage 1: Tighten to 7 Nm (62 lb-in).
Stage 2: Tighten an additional 40 degrees.

24. Bleed the high-pressure fuel system.

If you feel like this job may be too overwhelming or run into any issues, consider YourMechanic to get it done. One of our mobile technicians can come to your home and replace the fuel pressure sensor at your own convenience.