Code P1684 cleared but comes back!

Tiny
EM_KALIFORNIA
  • MEMBER
  • 2001 DODGE NEON
  • 181,280 MILES
My check engine light has been on for at least the past year now. I have cleared the code twice now by disconnecting the battery terminals.

It says clear after the first time of starting the engine and driving, just after the cables are disconnected. But when I go out to use the car the next day, the check engine light is right back on.

It has already failed the smog test because of this. My car runs fine and the battery has been tested and also runs fine.

I am at a total loss to figure this one out and so are several mechanics who have looked at the car. How can I clear the code for once and for all so that it stays GONE?
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Friday, August 16th, 2013 AT 6:26 PM

8 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Have the mechanics checked the trouble codes and repaired whatever is causing the light to come on? The light is coming on for a reason. You need to identify that reason and repair the problem. Let me know if trouble codes have been found.
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Friday, August 16th, 2013 AT 6:41 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I just realized that you had the code listed at the top of the page.

P1684 Battery Disconnected in the last 50 Starts

That light will take several restarts and it should shut off on its own. Don't disconnect the battery. That is what is causing it to come on.
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Friday, August 16th, 2013 AT 6:45 PM
Tiny
EM_KALIFORNIA
  • MEMBER
Yeah, um, I don't think so. The light has been on for over a year. That's many many restarts later.

No dice.
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Friday, August 16th, 2013 AT 6:48 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Has the vehicle been checked for any ground issues? The computer could lose power for a few seconds and think the battery was disconnected?
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Friday, August 16th, 2013 AT 6:50 PM
Tiny
EM_KALIFORNIA
  • MEMBER
No, it has not. I will look into that.

Thanks for the tip.
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Friday, August 16th, 2013 AT 6:53 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Let me know what you find. Also, talk to you mechanic and see if there is a power supply that maintains the computer. I can't remember if there is such a thing on your vehicle.
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Friday, August 16th, 2013 AT 6:56 PM
Tiny
EM_KALIFORNIA
  • MEMBER
I just noticed on the failed smog test the OBD Fault Code the inspector circled is P0601 (Internal Memory Check Sum Error).

So this appears to be a greater issue than the P1684.

I really hate to have to take it to a mechanic, but it seems like that is not something I'll be able to clear myself.
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Friday, August 16th, 2013 AT 11:38 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
P0601 --- With Dodge vehicles, the most common problem is the PCM. At this point, I feel either the PCM is bad or there is a wiring issue. Based on experience, I would say the PCM. Let me know what you find.
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Saturday, August 17th, 2013 AT 6:29 PM

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