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Unread 05-18-2010, 07:50 AM   #1
cskaplan
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Bad ECM? alternator won't charge battery

2002 sahara, 4L, Auto. having rough idle at cold startup so I wanted to look at the plugs. I pulled the long coil assembly off the plugs, they were OK. when I put the coil assembly back on I missed the last spark plug connection. When I started the jeep, it made really bad noises, was skipping, threw computer codes, stalled. Started it again, same thing. I re-seated to coil pack correctly on all 6 plugs and now the engine runs OK again, however I get "check guages", the alternator is not putting out any voltage and I am running off the battery at 11.9v. The battery connections look fine, I don't think I did anything to the wiring harness. The codes have something to to with the emission system, not charging or electrical. I suspect I have broken the voltage regulator in the ECM somehow. I did try a new alternator and it did not make any difference. Any suggestions before I get a new ECM?
Do I need to have a new ECM programmed, or can I get a used one for the same year, engine, and auto trans? (all stock).

Thanks for any suggestions!!

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Unread 05-18-2010, 08:11 AM   #2
cskaplan
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did key trick, found the codes -

Just saw the "key trick" to get the PCM codes:
P0622 Generator Field "F" Control Circuit Malfunction
P0443 Evaporative Emission Control System Purge Control Valve Circuit
P1495 Leak Detection Pump Solenoid Circuit Open Or Shorted

The last two don't make sense to me, but the engine was running really bad and making strange noises when I had it running on 5 cylinders. I hope these are false alarms and will clear.
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Unread 05-18-2010, 09:03 AM   #3
Jerry Bransford
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Try disconnecting your battery's negative post connector for 2-3 minutes & after reconnecting it, see if that helps. When you pulled the coil pack assembly off, could you have accidentally unseated the plug going to the alternator? I would check the electrical connections in the area, including the one coming off the rear of the coil pack assembly.
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Unread 05-18-2010, 09:45 AM   #4
cskaplan
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thanks for the suggestions, I tried them but to no avail. I also tried a new alternator, and it didn't make any difference.
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Unread 12-29-2011, 03:06 PM   #5
jonrck
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Alt not charging on 02 Wrangler

To: cskaplan, Hey there, I read your thread. Mine is the exact same circumstances. I replaced Alternator, checked wiring, and just ordered a Leak Detection Pump, Also I have a new PCM that I did not install yet (afaid to blow it again due to existing problem???

How did you wind up fixing your Jeep?
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Unread 11-24-2012, 01:35 PM   #6
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Unread 03-12-2013, 07:47 PM   #7
heymatt
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My 02 just tossed the same codes! Changed the spark plugs and the oil pressure sensor, cause it was runnng rough and the oil pressure was all over the place. Now I' m getting p0622, p0443 and p1495. Not charging but runs fine, changed the alternator. Still getting the same codes. Cleaned the battery terminals and the grounds to the block. Couldn't find any nicks or cuts in the looms on the passenger side of the engine.
Any thoughts?
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Unread 03-12-2013, 09:31 PM   #8
chris142
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Are the things that are throwing those codes on the same fuse or relay?
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Unread 03-13-2013, 05:09 AM   #9
heymatt
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Underhood fuses all looked good. I wouldn't think they are on the same relay. One is a charging issue an the second two are emisions related.
Previous responsders had the same codes, I was hoping they would chime in on what they found.
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Unread 05-22-2013, 03:03 PM   #10
smokeybear
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Same story, same codes, same attempted fixes. cskaplan - any solution in the last couple months?
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Unread 05-22-2013, 04:19 PM   #11
mukluk
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This is what I have so far -- the EVAP purge solenoid, generator source, and leak detection pump control/sense all use C3 (connector 3) on the PCM. Generator source comes into play here as it is the power from the PCM to the alternator which creates the field, enabling the alternator to charge the battery. Without the power from Generator source, there is no field created to be sensed (resulting in a field "F" control circuit error). Additionally, the leak detection pump gets its power from circuit K125, which is the Generator source.

The main possibilities that jump out at me would be a connection or wiring problem at C3, (pins 10 and 20 adjacent to each other, and/or pins 14 and 25 adjacent to each other), or a problem with C107.
8w-30-17.jpg  
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Unread 05-22-2013, 04:27 PM   #12
mukluk
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Here's the location of connector C107:
c107.jpg  
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Unread 05-22-2013, 06:42 PM   #13
smokeybear
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Thanks! I played with C107 and traced the wire loom from C3 back to the various connections out to the alternator. That's the path I laid the coil rail down on when changing the plugs, so it makes sense that's where I screwed something up. I just can't find it. Everything seems tight. Wonder if I toasted a wire when I didn't get the coil wire back on correctly and had some cracking that sounded like electricity arcing. Had a maxed out oil pressure gauge for awhile until I wiggled some wires and connectors along that wire loom, now it works. I might need to go connector by connector with electronic cleaner to make sure all the connections are as sound as they look.
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Unread 08-03-2013, 07:07 PM   #14
heymatt
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Mine ended up being a bad PCM. Had the dealer replace the PCM and flash it, back to normal.
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Unread 08-03-2013, 07:15 PM   #15
zero2three
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Heymatt: If you don't mind me asking how much did the dealership charge you? Mine is trying to get nine outta me. Just wondering if that is a reasonable price.
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