So been having an issue with the ETC light coming on randomly and throws a P0643 code. This progressed to coming on when on the throttle and then randomly hesitates and the flashes the low fuel light followed by both lights going off. Thought I had a shorted wire on the harness so went the rough it with a fine tooth comb to no avail. Replaced the throttle pedal with no change noted. Hoping someone has a direction to lead me. Currently have a used ecm and will be shipping it to GDE to have it programmed with my VIN and such to try that.

This is what I found! You may have already seen this?
Certainly appears to be an ECM issue...

Possible causes Faulty Engine Control Module (ECM) ECM harness is open or shorted ECM circuit poor electrical connection Shorted sensor on 5 volt circuit

P0643 JEEP Description The control module has 2 internal 5-volt reference buses called 5-volt reference 1 and 5-volt reference 2 . Each reference bus provided 5-volt reference circuit for more than one sensor. Therefore, a fault condition on one 5-volt reference circuit will affect the other 5-volt reference circuits connected to the reference bus. The control module monitors the voltage on the 5-volt reference buses.

Read more: https://www.autocodes.com/p0643_jeep.html

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2mic.Sec.Fuel Filter
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98 Dodge Cummins 24 Valve

My first instinct is that it sounds like a wheel sensor fault but the low fuel light doesn't make that seem as likely.


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I have been dealing with this for four months. Can't find any reference to the flashing low fuel light anywhere. I reset it the other day, left it idling for 30 minutes while I washed it (thought that might make me want to love it again) and it didn't flash the etc light. As soon as I put it in drive and moved it 15 feet it went off again.

I don't get any codes that I can read anyways. Getting ready to buy a scanner to continue to try to figure this out.

Mine did this after I installed a Weeks 1&2 kit and new GPs.

I have put in a lift pump, new rear speed sensor, crank sensor, reinstalled the EGR/FCV and old GPs, New battery, checked alternator...Been through the entire harness looking for frays, cleaned every connection. I guess I need to pull the harness to check continuity, or the other option is to part it out and cut my losses.