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Possible to fry the computer without blowing a fuse?

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Old Mar 25, 2011 | 07:54 AM
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RCB
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From: Indiana
Year: 1987
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Default Possible to fry the computer without blowing a fuse?

Well, in the ongoing search for why my wife's Jeep won't run (other posts on here), is it possible that the computer fried from where the O2 wires were dangling (cat had been stolen) but didn't blow a fuse?
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Old Mar 25, 2011 | 11:02 AM
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From: Tenn. and Mich.
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Originally Posted by RCB
Well, in the ongoing search for why my wife's Jeep won't run (other posts on here), is it possible that the computer fried from where the O2 wires were dangling (cat had been stolen) but didn't blow a fuse?
I don't think that's very likely. It would set a code though and might cause it to go into Limp mode making it run a little rough, and setting off the Check Engine light.
Try checking for any stored trouble codes yourself like this: http://jeephorizons.com/phpbb/viewtopic.php?t=2719
Turn the key on, off, on, off, on, off, then on and the digital odometer will start showing any codes. If no codes are stored it will show 55, which is End of messages, no codes stored. Codes disappear after 50 key starts if there's no reoccurence of the problem.
You can erase any codes after repairs by disconnecting battery cables and holding them together for 15 seconds to drain any residual charge, and codes, in the PCM. Then reconnect the cables and drive normally for a few miles so it can relearn the system parameters.
Or you can go to any auto parts/repair facility and they can check the codes and clear them if needed.
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Old Mar 25, 2011 | 11:54 AM
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Yeah no codes showed up. But the battery had been out for a while to charge, so it also gave me 12 (codes reset/power loss) and 55. I guess the dealership can't check the computer (checking if its bad or good) without it being in the vehicle. For the cost just to pull it in to their center, I can buy another unit which is probably what I will do, just in case. It's sending the right voltage, but it's not getting proper spark.
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Old Mar 25, 2011 | 12:02 PM
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maybe anti theft alarm issue from battery being out for a while??????????
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Old Mar 25, 2011 | 02:39 PM
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Can the alarm portion shut down the ignition?
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Old Mar 25, 2011 | 07:02 PM
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ASD relay WILL burn out if o2 sensor wires short. Found that out the very hard way, and chased the damn problem for over a week.
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Old Mar 25, 2011 | 08:06 PM
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im gonna say yes it is possible to kill an ecu without poping a fuse.
while wheelin in my 97 grand i ripped out the o2 wires they touched and the jeep died..i tried all the easy stuff first relays cps ect..(mainly cause there where no ecu's around) but one day found one and it started right up
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