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My 2008 Accord 4 cyl. has been acting up lately, and need some advice. It started two weeks ago with the radio cutting out for a second. Then the radio cut out and some of the lights came on the instrument panel. Next, when I came to a stop, the car quit but it started right back up w/ no problem. This week, it has quit on me every morning. On Monday, it quit twice and the check engine light came on. I got a P0685 code, PCM/ECU issue. The engine light has since went off, but it quit again this morning. The engine runs fine, but the idle speed seems low. Any ideas on what I should do?:dunno:
 

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My guess is an intermittent short in one or more cells of the battery. particularly if you are still on the original battery. If you have a spare battery lying around, switch it out. I bet the problem goes away.
 

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08 Accord EX-L (I4)- 138K
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I second that notion. Have that battery checked out just in case.

In addition, check your battery cables (positive and negative), especially since you said that your vehicle suddenly cuts-out from time to time. Ensure they are all secure and ensure there is no corrosion -either of the aforementioned could introduce high resistance into the circuit. If the cables visually check out (All secure and no corrosion), your battery is deemed satisfactory, and you are still having issues, then I'd recommend checking the cables with an ohm meter. With each side of the cable disconnected, ohm end-to-end to check for high resistance (should be good continuity with <1 ohm) and then ohm the cable to a good grounding point on the frame to check for shorts (should be straight "open"). Hope this helps!
 

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Honda owner since '84
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111 Posts
My guess is an intermittent short in one or more cells of the battery. particularly if you are still on the original battery. If you have a spare battery lying around, switch it out. I bet the problem goes away.
Please excuse me for butting in here....but I was under the impression that the only function of the battery is to START the motor. Once running, the alternator takes care of all electrical functions.

This is "old skool" thinking here, so correct me if I am wrong when it comes to all this new technology:)
 

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Elvira
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3,590 Posts
You still need the battery in the circuit since it acts like a "filter" for the spikes of voltage an alternator may output. When your alternator spins up and you mesure the output across your battery there are small but possibly dangerous spikes. the regulator should regulate this but with all the voltage sensitive components nowadays, if the battery were to be totally removed there is a very great chance you fry the ECU, etc.

As you know already you CAN run the car off the battery alone if the alternator breaks down. That's dependent on the charge level of the battery and what electrical circuits you need to use (lights,heater fan,etc.)

Miker
 
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