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No codes but engine check light on dash

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Old 07-08-2005, 08:21 AM
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Default No codes but engine check light on dash

Has anyone seen this before?

My engine check light has been on for a couple of weeks now. Yesterday, I left the ignition on by mistake and the battery went dead.

I re-charged the battery last night using a 12 volt charger via 112 volt house current - overnight.

I disconnected the charger and did an diagnostic analysis with OBD-2 software that is loaded on my portible PC. The software detected the PCM and I went to check for engine codes.

There were no codes listed and the software indicated that the malfunction indicator light was "off." My dash board light, "Check engine soon" was "on", however.

Does this have something to do with the battery going dead before the test?
Old 07-08-2005, 09:35 AM
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i do know that the Service Engine Soon light, and the Check Engine Soon light are 2 completley different things. being that you did leave your ignition on and let power drain, i would have to guess that you have a problem with the battery, cause the CES light doesn't monitor trouble codes as far as i know, and there aren't any codes for a dead battery that i'm aware of. have your battery, altinator and starter tested by a good shop for starters. thats my suggestion. it could be that the battery has a dead cell too.... wont know till you have it looked at. hope this helps.
Old 07-08-2005, 09:35 AM
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This happened with my pickup truck. I kept getting the light but no code. I changed the spark plugs and the light went away. I'm convinced that the light was caused by misfires.
Old 07-08-2005, 09:44 AM
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I noticed if I didn't see to my change oil light, ignored it for many miles, then it lite either the CES or SES lamp (cant remember which one) would come on after some time. When you turn ignition on does the change oil lamp light at any time?
Old 07-08-2005, 11:52 AM
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When I turn the egnition on the "change oil light" is OFF.

Thanks...

Oh yeah, I forgot to mention that car stumbles like a misfire during low RPM. It just started doing this so I figured it was the PCM getting pissed that I have not fixed what is wrong for a while now....

I went over all the PCM wire connections and injector cables yesterday before the test to see if any sensor/PCM cables were loose. I did not check the plug wires (Thunder Racing heavy duty), however.
Old 07-08-2005, 12:35 PM
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Let me explain what happened with my truck. I had the check engine light but no codes came up. I use an AutoXray scanner for the truck. One time I hooked it to scan, but basically I wanted to clear the check engine light because I've scanned it before and no code ever showed. This time, asI was scrolling through the menus, I quickly read "engine misfire." It didn't have a code attached, just those words. I quickly scrolled past it and tried to retrieve it again but couldn't. It was weird. I didn't think much of it, but later it occurred to me that maybe the light is because of misfires. So I decided to change the plugs. I have coil on plug ignition, so I cleaned the boots up real good and put some dialectric grease on the connectors, along with the plug change as I mentioned. I cleared the check engine light and it never came back. I can only conclude that what flashed on the scanner was actually the problem. FWIW.
Old 07-08-2005, 12:41 PM
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Thanks.

I changed my wires about 6 months ago. Also, I changed my plugs about two years ago with the heads and cam swap. I guess I will pull a few plugs this weekend and see if they are bad.

Thanks.
Old 07-08-2005, 12:53 PM
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OK I just read the Help section of the software.. It says under the malfuntion indicator light (MIL) section that all trouble codes are cleared when the battery is disconnected.

So I suppose I need to drive around some and collect the codes that are setting MIL.
Old 07-08-2005, 02:37 PM
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You won't believe this, my truck's check engine just came back again today (basically right after posting my message to you). What a coincidence that I wrote my posts feeling so confident I had the solution. All bets are off now. If you solve your problem, let me know, it might help me with my truck. Sorry, I tried to help.

Good luck!
Old 07-09-2005, 05:21 AM
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Here's the latest, I scanned my truck this morning (assuming it would be the same situation of a check engine light with no code), but the code P0442 came up (Chrysler) which is Evap system. I immediately checked my gas cap and it was half off and half on. So I still believe afterall that a check engine light with no code is because of misfires. I think you would be wise to check your ignition system (plugs, wires etc.) for misfires. Sorry about all the drama, but I stand by my original assertion. Let us know what you find.
Old 07-09-2005, 06:14 AM
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I missed your last post about software and the battery.




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