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Discussion Starter #1
People,

2013 Dodge Grand Caravan, engine light is on so I accessed the codes by turning ignition key to 2nd position 3 consecutive times and leave it there, codes appears, then if the only one it displays "DONE".

So, I did this and retrieved a code, I think it was P0456, but I wasnt 100% sure so I repeated the procedure. I got no code showing up, so I did it again, and nothing.

I drove the van a day or 2, and engine light is still on. So I figured maybe the code is displayed only once per drive(?). So I did the key trick again, and no more code!! Huh?? Anyone know why code does not show up anymore?

I thought of disconnecting the neg terminal from battery to clear, then see what happens. Comments appreciated.
 

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P0456 says evap emissions. If it went away a day or two later then it was probably the gas cap - wasn't tight enough or turned enough "clicks."

FWIW anytime you have a trouble code you can take it to AutoZone (prob other chains too) and they will read them with a handheld OBD reader for free. Offer parts or whatever but you are not required to purchase anything.
 

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Discussion Starter #3
P0456 says evap emissions. If it went away a day or two later then it was probably the gas cap - wasn't tight enough or turned enough "clicks."
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So, tree, is it still normal for engine icon to show even if there are no codes to retrieve? I did check gas cap, it was tight.
 

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All of the big automotive chain stores will read codes for you. Well, now Autozone hands you the code reader and sends you out to plug it in; it reads and stores the codes, and you return it to them. They plug it in, and the computer provides a printout of the codes and the likely causes.
 

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PE, why are you doing htis goofy s... with turning key on and off, instead of using a code reader? It's 2013 vehicle, you know. Who knows, if it even is supposed to have codes shown that way. Just go to any parts store, they'll scan it for you.
 

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Or go to Wal Mart and buy a perfectly good basic code reader tor $25.

PE, why are you doing htis goofy s... with turning key on and off, instead of using a code reader? It's 2013 vehicle, you know. Who knows, if it even is supposed to have codes shown that way. Just go to any parts store, they'll scan it for you.
 

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Exactly. And how often do you get an ABS code? Not very. If you are really budget conscious a simple $25 scanner will work 95% of the time and save you from screwing around at Advance Auto or Pep Boys to get a scan. Or you can really splurge for the $75-$100 one that has ABS.


But the OP doesn't have an ABS code.
 

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I agree with preferring an actual scanner, whether borrowing one at the auto parts store or buying one, over the vehicle based one. In my experience, an actual scanner is more specific, and more apt to indicate a current problem versus a past problem. And given the number of repairs you have done, I would really recommend buying one if the budget justifies it. Back to your original post though, yes, if the code went away and the light remained on, I would try disconnecting the battery for a few minutes and see if it resets the light. Having had that exact problem on at least two vehicles, I also agree with 3onthetree that it could very well be the gas cap. I had one that the doggone cap would start a little crooked once in a while and throw a code, so finally ended up replacing the cap, and another, one of my company trucks, that when it said tighten the cap to the first click that's what it meant because going any farther would send a code almost every time. If it's not the cap, could also be something in the evap system, and that's where having a scanner can help nail it down closer.
 

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So, tree, is it still normal for engine icon to show even if there are no codes to retrieve?
Not an expert on OBDII, but DTC's will be active ("Stored" code) if it exists for 2 or more drive cycles and the Check Engine Light is directly associated with having a DTC. Only if it has detected 1 drive cycle failure will it list a "Pending" code and the idiot light does not appear yet. So if you have a light, you have a code, but you can have a code without the light.

If the problem goes away on its own after running through future drive cycles, then the idiot light and corresponding "Stored" DTC will disappear. That is a common occurence with untight gas caps, as it unknowingly gets fixed during the next gas fillup. A more complicated emission failure like vacuum leak or oxygen sensor usually don't go away on their own, they need repaired.

Disconnecting the battery does not clear Stored DTCs, but it may turn off the Check Engine Light until the drive cycle confirms the DTC again. You have to use the OBD scanner to clear a code, but again, it will show back up if the problem has not been fixed.

P.S. I believe, not sure though, for ABS problems OBDII-equipped cars might all have a separate idiot light for that rather than using the Check Engine Light.
 

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Discussion Starter #12
PE, why are you doing htis goofy s... with turning key on and off, instead of using a code reader?
Cuz it works, UK. It is a well known method. AND I retrieved the code 1st time around. The mystery is why cant the van allow me to repeat it?

Yes, I know I can go to AZ- did it many times before. Hate to drive there...LOL.

I will though, if I must. Thanks, UK.
 

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I went through all the replies- thanks, people. Until I see an actual problem with a free scan from AZ (in the past they worked out well) I will avoid buying another gadget. I will wait a few driving cycles, then see what happens. I doubt it is a serious driving risk, but will keep an eye out.
 

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LOL... you will be here again and do this all over... unless you get the gadget and have it when you need it next time. And there WILL be a next time and another next time, etc., etc. That's when most tools are most useful. It would maybe your and our lives a lot easier. ;-)


I went through all the replies- thanks, people. Until I see an actual problem with a free scan from AZ (in the past they worked out well) I will avoid buying another gadget. I will wait a few driving cycles, then see what happens. I doubt it is a serious driving risk, but will keep an eye out.
 

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As I understand it, the light basically comes on a sensor goes out of range (voltage). Whenever the light comes on, a code is stored. If the sensor then comes back in range, the light goes out. But the code remains stored. So you could theoretically have a number of codes stored, without the light being on. These codes remain until manually cleared.
 

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As I understand it, the light basically comes on a sensor goes out of range (voltage). Whenever the light comes on, a code is stored. If the sensor then comes back in range, the light goes out. But the code remains stored. So you could theoretically have a number of codes stored, without the light being on. These codes remain until manually cleared.
Thanks, Hue- this may be beyond my expertise, clearing codes. But I am prepared to visit AZ for this soon, then hopefully fix it all up. Will let yous know what happens.
 

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Car ECMs also store pending codes for faults that haven't reached a set frequency or severity before the light is set. Many scanners will also read these which can be handy if diagnosing an intermittent issue.

And PE, clearing codes is NOT beyond your expertise. With a scanner it is as easy as deleting an e-mail, you just click "erase codes" from the menu and confirm if it asks you. You really should have one as often as you seem to work on cars.

Thanks, Hue- this may be beyond my expertise, clearing codes. But I am prepared to visit AZ for this soon, then hopefully fix it all up. Will let yous know what happens.
 

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Car ECMs also store pending codes for faults that haven't reached a set frequency or severity before the light is set. Many scanners will also read these which can be handy if diagnosing an intermittent issue.

And PE, clearing codes is NOT beyond your expertise. With a scanner it is as easy as deleting an e-mail, you just click "erase codes" from the menu and confirm if it asks you. You really should have one as often as you seem to work on cars.
Thanks for the kind words, Ray. I might just have to look for one of those. OBD2. But I wont be using it on my 87 Sunbird GT- use a paper clip for that........LOL
 

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Hey Papereater, not trying to coax you into something that you don't want or need, but after reading this thread happened to remember something I thought I would share. I used to rely on the onboard displays for trouble codes too but several years back ran into an emission problem on the wife's car that I couldn't track down. Had it scanned at the parts store a couple of times over a couple of weeks, but it was so intermittent that it wouldn't even show up in the history so on the third trip back to the store I finally bought my own scanner, and was able to isolate the problem the next evening. One more trip back to the store for a $10 part, 20 minutes to install it, and it was done. I don't know how long I would have otherwise dinked with it before throwing my hands up, but figured I paid for the scanner on that first job.
 
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