Daytrip65

Hello, new to the forum obviously but also new to jeeps.

I have a 2000 Cherokee 4.0 but I'm learning that the distributor being present means it's a 99 or older engine.

I started having intermittent charging issues, the Check Gauges light would come on the and gauge would drop to 9. Next time I started it it would be charging fine. I pulled the alternator and the battery and both checked fine. Had a mechanic look at it and he pointed me to the ECM.

I bought a used ECM from a 99 and swapped it out. Now it will start (and is charging) and run for a few seconds then die (seems like a common problem). I put the old ECU back in and it starts and runs fine.

I assume I have a bad ECU or need to have it flashed.

Not sure if it's a security issue or not, it didn't have a remote when I bought it and it had a door lock issue that was running the battery down. I removed the passenger door/window lock module to temporarily solve that issue if that matters.

Any ideas?

captainwoot

Normal black key or a round head grayish looking key? If it is the gray key, you have a security issue. Had the same charging isse with my 98, alt would test fine but when i disasembled it the slip rings / brushes were worn out

landude

You had the battery load tested correct? I would start by cleaning every ground you can find and clean them well..

freegdr

Are head lights flashing ?

Daytrip65

It is a round key but it's black. Not a chrysler/jeep key though is says Axxess+ on one side and 19R2 on the other.

If it's a security issue would it do it with one ECM but not the other?

Headlights are not flashing.

The battery was tested but he just tested it on the counter and then in the car at idle. I thought ground issue as well but I figured that the issue would be present with either ECM if that was the case.

Daytrip65

If the ECM I bought came from a jeep with a security system and mine doesn't have one could that be the issue?

It seems that it's doing exactly what it should do if the security system was armed. Start and run for a few seconds then nothing.

captainwoot

Yes if it came from a jeep with a security system, that is the problem. You need to find one without.

Daytrip65

Good to know. Is there any way I can have this one reflashed or is sourcing another one my only option?

Roler

The engine immobiliser feature will not let it run for 'a few seconds'. It will cut spark and fuel off after about 1, max 2 seconds running. This feature can not be flashed, by-passed, deactivated or whatever you try to get around it. It's integrated in the ECU.