Check Engine Light

We have a 2006 Kia Sorento EX with approx 29,000 miles on it, mostly local running around in the Palm Springs CA area. The check engine light keeps on coming on at fairly regular intervals. The dealership ran diagnostics and said it was the gas cap not being tight enough. We are now on our 3rd gas cap and it still keeps on happening. It will go off for a number of weeks, then suddenly come on again. What els can we do to find out what is wrong? The nearest dealership in about 80 miles away, so not very convenient to just drop into!

Find out from the dealership what the actual, specific code was - there are hundreds and they come in the format P0123.

We can obviously narrow your down to a leak in the evaporation system (but there are quite a few codes for the evap system). These days cars collect gas fumes and send them through a system of hoses to the engine where they are burned rather than being vented to the atmosphere. You have a leak in that system. The gas cap is one thing that can leak. I think it is time for them to move beyond that to check out the rest of the system.

The light can also squawk the same code if you happen to fill the tank with gas while the engine is running. Do you happen to do that every couple of weeks?

To add more to the mix, the EVAP:PURGE cycle may not even occur if the tank is too full or to close to empty on some models. Vast differences from manufacturer to manufacturer on how/when it operates. It also tends to be a cold start readiness state. It may not come on if the PCM is reset and you don’t complete a “good trip” as defined by your PCM.

As far as drivability and safety are concerned, your nag light is meaningless… The on board computer thinks the fuel tank might not be venting properly so it turns on the light. So what? This does not effect the operation of your car in any way. if when you ever need an emissions test, be sure the light is off before you drive in. Don’t buy any more gas caps…

The dealership has been wrong on the cause of the trouble code. You don’t need the dealer to repair the vehicle. Any decent repair shop can handle it. Ask friends and aquaint for one.
The problem seems to be in the evaporative emissions control system. This can be very expensive to repair, especially in CA. You could just let it ride. Then, when state emissions test time rolls around, go for the test when the check engine light isn’t on.
Another way to save money would be to buy an OBD code reader, and read the trouble codes when the check engine light comes on. You could, then, bring those codes here for advice.

Three gas caps in a row means someone is wild guessing and not interpreting the code, or codes, correctly.

Drop by a Checkers Auto, AutoZone, or whomever and have them scan the car. It only takes a few minutes and is a free service.
Post any code or codes back for discussion.

Just being curious here, but when the dealership gave you the gas cap diagnosis did they:

  1. Write up a repair order followed by your car going into the shop for a tech?
  2. Service writer or manager hooked up a scanner and gave you this diagnosis?

CA (California) has a law which forbids auto parts stores from using a scanner on customers’ cars. For $50, Bob can buy a scan tool, and do scans as many times as he wishes.

First, let me say I know nothing about Kia cars. But, a couple years ago, I had an intermittent CEL on my 2002 Toyota Sienna, also an evap problem, “small leak”. Knowing from my own work as a Senior Technician on high tech electronics that troubleshooting an intermittent failure is an extremely expensive process, if you must pay someone to do it, I chose to keep a log and keep driving it.

Since the cap is indeed the first item on the list which must be eliminated as part of a troubleshooting process, I also replaced it twice, since I didn’t have to pay big labor charges. And, I examined all the hoses and other items I could see relating to the problem.

At one time it went a month or two without failing.

Codes varied, but were generally around P0440; 0442; and a couple others similar, but the log book I used was converted to other uses after the problem was solved. Perhaps 0446, not sure any more. I did have my own scanner, and sometimes even left it running while driving so I could see when it failed. As another good contributor said, the algorithm of the evap check seems to be different with different makes. One algorithm I found on line, I think GM, said it checked at specific outside and engine temps, and with a certain amount of fuel aboard. When mine failed, it was usually about 5 minutes after the car was started, then it didn’t fail again until the car was parked for a while.

Finally, on the now defunct Sienna Club, a man reported he had the same exact symptom, but he had two Siennas. He swapped parts until the symptom moved to the other car. That happened when he swapped the canister assembly itself. He had it replaced and problem went away.

He said he believed there were some “low pressure” valves on there, and he theorized one of them got sticky or something like that.

I cannot at all say your Kia is the same problem, but I do point it out for your information.

In my case, I thought about what he said, and took it to the dealer and told the writer I wanted the canister assembly replaced, that it had been intermittent, and there was no point in me paying a mechanic to look for something that was very unlikely to happen at that exact time, within his time constraints.

He said they sometimes had people who believed they knew what the problem was, and they would be glad to replace the part on my say-so, as long as I signed a waiver that if the part did not fix the problem I accepted responsibility. I was glad to do it, because it was my intention to take responsibility all the time.

That has been some considerable time, don’t remember exactly how long, at least a year or two, and no more problems. The problem began according to my fuel log June 2007, so it was probably fixed in early 2008. Two years with no more failures.

Let me add here a note explaining why I usually take my car to the dealer to save others from typing in a lecture reprimanding me for taking my car to the dealer. McAllen has a problem, which I will not bother to describe. There are a few really good mechanics in McAllen, but they are well known, thus are so swamped you need to take your car and leave it until they get down to you, which can be several days.

Not only do I only have one car, but we are usually preparing to go somewhere else when we return to the States. Toyota can replace parts correctly, thank God, and I get it back same day. The other good news is, so far at 165,000 miles it hasn’t needed that many repairs, if it starts coming apart I may have to change my plans.