02 Liberty loses all electrical power while driving.

I did a search, but could not find anything. I was driving my 02 Liberty Limited, while for just a split second, I lost all electrical power. It happened so quick, that the engine quit firing for a split second, but re-fired. My radio reset to 12:00, my stations presets reset, my overhead onboard computer reset, and when the engine re-fired, all my dash lights came on for a moment, the same way it does when you first start the engine. Im kind of ruling out anything with the battery and alternator, considering how rapid it was, and Im thinking something like the main power source to the fuse box. I checked and cleaned the battery terminal, all the wiring is visually sound and tight Thank you. I would appreciate any suggestions, thank you.

Check your batt wattage while off and while running should be in the neighbourhood of 12v to 14v when running

I had something like this happen 2-3 years ago. It was night, on my way home. I was going over Rail road tracks and soon as I finished crossing them all my warning lights came on. then the dash, radio and exterior lights turned off for a second and then all lights turned back on like normal. No Warning lights after everything turned back on. Everything happened in a matter or 3-4 seconds.
I came home and checked for any codes and there where none.

Engine didn't loose power though as I had my foot on the gas because I was going up hill.

I thought going over the tracks knocked something loose (like a fuse or connector) but I drive over the same tracks at least once a week and the Jeep has been fine ever since. I've even hit some pretty good pot holes since then and never been able to reproduce the issue.

So, since I'm a Technology Specialist. I viewed this in a matter of how a PC works. I figured the Jeep's Computer had a "system crash" (to give what happened a name) and it rebooted. If that was really case or not I'll never know but I'm not longer concerned about it.

Thanks for the feedback. I had the same problem happen yesterday. It now has happened 2 times in 9 days. I have done some research, and its kind of pointing towards a faulty Body Control Module. I was hoping anyone would have some experience on dealing with them.

Also as a computer tech, the first sign of something wrong with a main function of a computer is the blue screen of death, and a reboot. If it doesn't come back on, good. But plan to replace a part soon. If the main CPU on the Jeep is doing this, it could start doing it more frequently until it completely fails.

Same thing happened to my '04. Had to have the BCM replaced. Luckily, it was still under extended warranty.

A bad ground check em out....or even serious drops in voltage could cause this.
I would like to see you use a hydrometer on each cell if it has removable caps.
Also do a load test on the battery, and ensure it passes to eliminate that aspect.

Simplest things first

My wife constantly reminds me to check the simplest things first. So, check your grounds and power connections first. Start at the battery and check the cables. Check both positive and negative connections going to the body and engine. Corroded and/or dirty connections can cause the problem you experienced. Had a similar problem on a Honda and it was a corroded connection.

Thanks for all the feedback. I will check the ground. Im not very familiar, but there is one particular ground ( ground 202) that seems to work in conjuction with the bcm, the powertrain control module, and a whole lot of other electrical components. I have read that its somewhere in the left kick panel. Also, if anyone knows the location of other notable ground, it will be greatly appreciated, thanks. I will keep the post updated with any findings.

UPDATE, last night, while driving, my check engine light came on, and noticed that the engine was not shifting into final gear (55mph@ 2700rpm). I pulled over, shutdown the engine, restarted, and vehicle drove normal. Once home, I scanned code P0750, shift solenoid a malfunction. I erased the code, and its been driving normal for the last 40 miles. I believe that the malfunction is a result of the same faulty electrical problem described in the first post. I was wondering if anyone knew if theres a relation between the bcm and transmission, or perhaps the power distribution module and the ******, Thanks.

I doubt that it is the BCM....this has little to do with the engine running or cutting out. A problem with shifting would be from the TCM.

Check the battery terminals are clean and tight, the negative lead going to the chassis is clean and tight and the grounding strap that grounds the engine to the chassis is clean and tight on both ends.

You can connect a voltmeter to the cigar lighter/power outlet on the dash so as to monitor the voltage while driving....you may see a sudden dip or rise in the voltage as you pick up one of these funnies. Also make a note if these problems occur as you do something ie. switch on the Air con, turn on the wipers etc.

You can download the 2002 KJ Service Manual here...includes wiring diagrams and locations of connectors etc.

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