There's different fault LEVELS that can trigger a CEL and many of them present no immediate danger to the engine. The faults - like a leak in the EVAP system or a catalytic efficiency problem to name a couple, will simply keep the CEL illuminated. More severe faults where the ECU believes it may not have complete control over the engine will illuminate the CEL AND place the car in LIMP mode where it starts using pre-programmed parameters to keep the engine running. ALL CEL's should be investigated but if you're not in limp mode it's likely you're not going to damage anything while driving a short distance.
Recommend an OBD II scanner?
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PeteK
GT Owner
Kendall, does the CEL flash when the problem is critical, like in other cars I've seen? I wouldn't know if it does that in the FGT, as I haven't seen a CEL in mine--and hopefully never do.
twobjshelbys
GT Owner
Yes. If the light comes on you're ok to drive but if it flashes stop now. if it does the engine is in trouble and you'll want to stop anyway
twobjshelbys
GT Owner
My car friend having a beer says that the cel light can be triggered by a blown fuse. Anything else not working?
No apparent blown fuses; thank you friend for his input please. Update: My new Innova 3100RS scanner arrived, I connected it, turned on the key and it immediately found code P0442. Google search says: "The OBD code P0442 indicates a small leak in a vehicle's evaporative emission control (EVAP) system. What it means: A minor leak in the EVAP system, which traps fuel vapors in a charcoal canister until the engine can burn them. Possible causes: Loose or incorrectly affixed gas cap, a faulty vent or purge valve, a crack in a fuel vapor hose or tube, or a bad vent seal. How to fix it: Remove and reinstall the gas cap, or use a smoke machine or water with dish soap to find and fix the leak." So I feel better that it's apparently not too serious anyway and prob OK to drive.
Of course the GT has no gas cap to remove and reinstall, and since my fuel filler neck has recently been replaced due to the broken flapper, I poked my finger down thru the filler to make sure the flapper does spring back up closed, and it does seem to, positively (although maybe it's just not quite seating). Car was sitting at less than 1/8th tank of fuel, so I added 5 gals of ethanol-free, cleared the code and drove 30 miles tonight. The light was still out when I got home. So I guess I'll continue driving it and see if the light returns, and if so maybe need to do a smoke leak test?
Remember on my way home from Detroit I drove the GT on the Blue Ridge Parkway for a day, at altitudes of over a mile, then came home to Florida 80' above sea level. Could that elevation (pressure) change have caused it?
Any other thoughts?
Of course the GT has no gas cap to remove and reinstall, and since my fuel filler neck has recently been replaced due to the broken flapper, I poked my finger down thru the filler to make sure the flapper does spring back up closed, and it does seem to, positively (although maybe it's just not quite seating). Car was sitting at less than 1/8th tank of fuel, so I added 5 gals of ethanol-free, cleared the code and drove 30 miles tonight. The light was still out when I got home. So I guess I'll continue driving it and see if the light returns, and if so maybe need to do a smoke leak test?
Remember on my way home from Detroit I drove the GT on the Blue Ridge Parkway for a day, at altitudes of over a mile, then came home to Florida 80' above sea level. Could that elevation (pressure) change have caused it?
Any other thoughts?
twobjshelbys
GT Owner
Ta Da! We have a winner.
If you had pulled the readiness indicators you would have seen that your Evap tests were incomplete. The evap ones are sometimes the hardest to get because of the timing from a cold start, outside temp and the short drive time to warm up plus a 1/2 to 3/4 full tank. In a "cleared from reset" like you get from a battery disconnect or any other code reset, you get a handful of tries but they all start with a cold start and if you don't get the results, it resets and starts over again. Thus the lag between when you had the filler neck replaced and when the CEL appeared. Eventually the failure to close changes from a pending code (we're in the retry loop) to a hard failure and lights the light.
This means you have a leak in the gas cap. Like you said, you have no cap. So time to go back to Rich and figure out where the filler neck isn't connected. It's still broken. Sorry. But that's the fact. With some very low probability it could be in other places but 99% it's the last thing that was touched. The only for sure way to tell is with a smoke test.
No amount of playing with gas and additives is going to make this go away.
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twobjshelbys
GT Owner
Yeah. Here's your dilemma. If you continue to drive around with this little pesky leak, and your CEL light is on, any other REAL PROBLEM WILL BE MASKED! That can be fatal to the engine... Certainly not a crap shoot I'd take with a 500K car to fix a $500 gasket or o-ring... (which on any other car is $100-ish mostly labor) Ford had that filler tube thing and ditched it for a reason.
I'm relating to this exact issue from personal experience. I had the exact same code on my 2004 Dodge pickup. Replaced the cap. Still came up. In hot ambient temp I could occasionally get a whiff of gas. It was a fuel pump connector at the top of the tank that was leaking vapors. They replaced the fuel pump and in the process broke another of the plastic connectors to tubing and had to replace the fuel tank which was no longer available from Dodge. And now my gas leak smell is back...
Thanks - When / if the code returns, I have no intention of not getting it resolved ASAP.
Page 10 of my '05 GT's Owner's Guide says, "If the light is blinking, engine misfire is occurring which could damage your catalytic converter. Drive in a moderate fashion (avoid heavy acceleration and deceleration) and have your vehicle serviced immediately."