The Check Engine Light comes on, diagnostic code indicates gas cap or two other possible causes. I have replaced the gas cap twice and still have the indicator on. I disconnected the battery and drove

Renault Scenic P242F Engine Trouble Code When the check engine light comes Renault Scenic P242F code on the first you should check is the gas cap. Pull over, retighten it, and take a look at the cap to see if it has any cracks in it. Continue driving and see if the check engine light turns off. Alternately, you can purchase a gas cap for about $3 at an auto parts store. All you need to do is take the old one off and screw on the new one. If you've already made it to the store, you might as well just replace it. While not car-threatening, it's good to take care of this right away to improve gas mileage.

Renault Scenic P242F Code Meaning :

P OBD-II Diagnostic Powertrain (P) Trouble Code For Engine Fuel And Air Metering (Injector Circuit Malfunctions Only) O2 Sensor Heater Circuit Malfunction Turbocharger Boost Sensor A Circuit Low When you check Renault Scenic car engine light came on code P242F the reason should be . However manufacturer may have a different definition for the P242F OBD-II Diagnostic Powertrain (P) Trouble Code. So you should chech it on our car models. P242F Fault Symptoms :

1. Check engine light comes on
2. Engine stalling or misfiring
3. Engine performance issues
4. Car not starting

If one of these reasons for P242F code is occuring now you should check P242F repair processes.
Now don't ask yourself; What should you do with P242F code ?
The solution is here : Renault Scenic P242F Possible Solution : Disconnected, dirty or fouled spark plugs are common causes for engines that won't start. Spark plugs typically need to be replaced every season or 25 hours of use. You should also check that the spark plug gap is set properly. If your spark plugs look good, problems with your ignition system can also preventing a spark. These can range from a faulty spark plug lead, shorted kill switch or flywheel key damage.
P242F OBD-II Diagnostic Powertrain (P) Trouble Code Description P242F OBD-II Trouble Code The Powertrain Control Module ( P242F code. Reason For P242F Code The reason of P242F OBD-II Engine Trouble Code is O2 Sensor Heater Circuit Malfunction. Parts or components should not be replaced with reference to only a P242F DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.

the code refers to the EVAP system and caps , hoses , purge valves and purge solenoids are all involved in your problem

Sorry, but there is no "sensor at the fuel cap". Therefore, there is no code that says "sensor at the fuel cap". There is, however, a Diagnostic Test Code (DTC) That indicates a possible problem with the fuel cap.
(HINT: When you want information on codes, it is usually wise to include the code number that you are getting - that way, it can be looked up, instead of GUESSING at what the problem is from a code description that some generic code reader is telling you..)
DTC P0457 is defined by SAE J2012 as "Evaporative Emission System Leak Detected (fuel cap loose/off)"

At this point, I am ASSUMING this is the code you got.

This DTC is set when the Powertrain Control Module (PCM) detects that there is an in-tank pressure drop that is more than 7in. H2O within 30 seconds directly after refueling, or there is excessive purge (fuel Vapor) flow more than .06 lbs. per minute. Possible causes are:
> Fuel filler cap not installed after refueling
> Fuel filler cap loose or cross-threaded

There are other malfunctions that can also cause this code to set, but it will be accompanied by other codes indicating other possible failures.
If there are no other Evaporative Emissions System codes present, then there is most likely a problem with the way your fuel cap was put on the last time you got fuel.

Check your fuel cap and make sure it is on correctly and is tight.

It would be really nice to know EXACTLY which code you are getting. However, since you mentioned gas cap, I will assume that you are getting Diagnostic Test Code (DTC) P0457.

First, you need to understand that DTCs (or fault codes) NEVER tell you what parts to replace. They only tell you which of the many circuits and systems monitored by your onboard computer network is malfunctioning. The circuit or system must then be properly diagnosed to determine the actual CAUSE of the failure. To do that, you need to follow the correct diagnostic procedure and you also need to know how the system is supposed to work, so you will know a malfunction when you see it.

Here is what is causing your confusion:
The standard definition for DTC P0457 is "Evaporative Emission System Leak Detected (fuel cap loose/off)"
Please note here that the part about the fuel cap is in parenthesis. The MAIN description is "Evaporative System Leak Detected." This fuel cap part is only because this code is very often caused by people not putting their fuel cap on correctly, forgetting to put their fuel cap on at all or losing it, or refueling their engine with the engine running. So, this part of the DTC description is NOT telling you to replace the gas cap. It is only telling you to check for a loose or missing gas cap for a possible cause because it is so common.
What the code REALLY MEANS is that there is a HUGE leak in your EVAP system.

Please also note that a fuel tank pressure (FTP) sensor that is not working correctly can also cause the computer to "think" that there is a huge leak when there is not...Hence, the need for proper diagnosis.

The operation of the FTP needs to be verified to make sure it is not "lying to the computer. All of the hoses, lines, tubes, charcoal canister, and other components of the EVAP system need to be inspected for cracks, tears, breaks, etc. that would cause a leak in the system.

take it to autozone and have the fault codes read for free
the charcoal cannister that they speak of is the EVAP cannister and if there is a problem with it it will show as a fault code
it has a purge valve and a purge valve solenoid for operation , both of which can be replaced separately
when you hear" I think " , time to find an accredited service center that has experience on your make pf vehicle and get a second opinion
the gas tank neck is a rubber section and comes up in the code as a small leak
a simple loose gas cap will put the light on

You've probably got a broken hose. Smoke check would pinpoint the source of the leak.

Check your gas cap first.

Replace the cap and have the code cleared at Autozone. If the problem comes back, look for cracks in the lines between the gas tank and the evap canister behind the battery.

Did you change the gas cap with a Honda gas cap? Tighten it at least three clicks?
Also, Honda recommends that you never top off the tank when getting gas (only go to the click-off of the pump; otherwise you can get back flow into the system that will cause the code).
Tightening or replacing the cap will not immediately cause the light to go off; it can take up to three days of driving for the light to reset.
To check if your readiness codes (emission system) are set, turn the ignition to ON (II), without starting the engine. The Malfunction Indicator Lamp will come on for 20 seconds. If it then goes off, the readiness codes are set. If it blinks 5 times, the readiness codes are not set.
You can, of course, try resetting your engine light to see if it will come back on (which it probably will). I believe the procedure is:
Turn off the engine.
Press and hold the Select/Reset knob (odometer) in the instrument panel, then turn the ignition switch to ON (II).
Hold the knob for approximately ten seconds until the indicator resets.

Hope this helps you.

i would start with the gas cap and have them read the
code again. its a cheaper way to go first

sounds like you have a code for evap leak detected. thats why you have been told to change the gas cap. this means you have a vapour leak in your systam. check all line and hoses to and from gas tank for leak. the filler hose and lines may be leaking. good luck please rate this.