'02 Neon SE, possible ECU issue?

[NeonLights]

There's a guy selling a Neon that he says only needs a new ECU.

He tells me it'll turn on, run and drive, then, eventually, the gauges will go out of wack and the gauge lights will all start flashing.
After this happens, the car dies and the battery drains. He says he's talked to a dealership, people at auto parts stores and they all tell him it's the computer.

My thought was to just swap it with another ECU of same year/tranny but he says no.

The dealership and auto parts stores tell him he can't swap it out with a used one because his has a grey key. Cars that have the grey key and are SE, if you swap it with any computer, it can mess up the theft system.

The car has had literally everything replaced including the transmission, which he says he had bigger gears put in so it'll shift at higher RPMs. He's put about 15,000 miles on it since it's been put in.

I can't seem to find any other posts, anywhere, that have had the same symptoms.

Any clues?

[occasional demons]

One: What year is the car?

Two: What transaxle?

Three: Yes, a used PCM can be installed, but the SKIM and VIN must be flashed at a dealer. It seems here lately that some dealers are telling customers they cannot flash used PCM's and will only install a new one. If this is the case, find another dealer to deal with.

Whether or not the PCM is the actual cause of the problem, It is possible, I guess. The cluster is operated vie the PCI bus wire by the PCM. All the gauges, except the fuel gauge are PCM controlled.

So the fuel gauge should not be doing what the other gauges are.

But I wouldn't think a cluster alone would kill the engine.

[BigMac]

If it's that simple of a fix, tell him he should do it himself if he expects to sell the car for anything more than a song.

In other words, don't take his word for what the problem is. For one thing, if you replace the PCM (ECU) yourself you'll have to have it towed to a dealer to be reflashed because it won't run at all once it's changed. (Or change it in the dealer's lot so they can reflash it immediately.)

[gilly02le]

if the cluster is losing its connection, the car will not run. The car does not start if the cluster is unplugged or loose. I forgot to screw it down once and had the car stall while driving, had to push the cluster back into its socket, and sneak home to throw the screws back in... something to look at anyways.

[trojmn]

He tells me it'll turn on, run and drive, then, eventually, the gauges will go out of wack and the gauge lights will all start flashing.
After this happens, the car dies and the battery drains.

Check the battery. Low voltage does wierd things at low RPM were the alternator cant keep up. gauges go nuts, solenoids cycle, lights flash, like the car is possesed....

the key would be what do you do to get it to run and drive again? and how long will it run for?

Have the guy charge it up fully, take if for a "test drive" right to your nearest auto parts store and have them test the battery and alternator output. the ECU controls the voltage and would prevent you from charging the battery. price it for the worst case scenario.

Tro

[occasional demons]

Hmm, I could of sworn I had my car running with no cluster. It could be a SKIM issue tho. IDK, it has been a while since I had it out.

But I generally try dumb stuff like that, just to see what does happen.

[Danteneon]

It must be a SKIM thing that keeps the car from running without the cluster. I drove my 2000 non-SKIM and all I lost were brake and turn signal lights.

[occasional demons]

Brake lights are overrated.

I thought it ran without it, but I only started it, I didn't drive it.

[Danteneon]

I thought the same thing! The local cop who pulled me over after noticing that I was using my parking lights as brake light substitute did not agree however.

I had a very hard time convincing him that the car was not stolen since the cluster was missing