Car quit while my wife was driving it. Unable to start it and my code reader can't link to the car(works fine on our other car). I am quessing the PCM/Computer is bad. Any input to confirm this or what else it could be would be appreciated. Car is a 1999 Neon Sport DOHC automatic with 104,000 miles. Car is new to us. Have had it 2 months.
Thanks

 

Not very often that the PCM goes bad. Is the battery fully charged? Ultra clean terminals? the Neon is a bit touchy about that, they have to be extremely clean and megatight it seems...

You should be able to pull a PCM from a salvage yard for under $50. If you have a hard time finding one at a decent price, PM me and I'll try to point you in the right direction. You could even borrow a friend's '97-99 Neon just for troubleshooting to make sure it's not the PCM at least...

When you say it won't start, is it clicking at all? Turning over but not catching? Can you hear the fuel pump whir up when you first take the key to "On"?. Is the Check Engine Light (CEL) coming on, staying on? Also, what type of code reader? Some only read certain protocols...

 

Yes the battery is fully charged, no the check engine light is not lighting. The engine spins but does not fire. The battery terminals look okay but I will clean them anyway tomorrow. My code reader is an Actron OBDII AUtoscanner CP9135 so it should be fine for this car. Tried a used PCM with no luck, but it was from a U-Pullit yard (only place near me) so who knows if it was any good(only one they had). I can't hear the fuel pump but not real quite outside right now. I will try again early in the morning.
Thanks for the input.

 

When you first take the key to "On", the CEL should light up for a couple of seconds, then go out. If this isn't happening, either the bulb is bad or the PCM (both of them, apparently) is fried. The bulb is easy enough to change out, just swap it with one you don't use as much, like the hazard flasher bulb.

If the CEL is doing its thing properly, you can at least try to pull the 2-digit codes using the key on/off method.

Assuming he PCM is good, when you take the key to "On", the PCM will activate the ASD relay for about 1 second, which starts the fuel pump to pressurize the system. Then when you take the key to "Start", the ASD relay is activated again, meaning the fuel pump, fuel injectors, and O2 sensors should all be running. If there isn't a crank signal detected shortly afterwords (2 revolutions?), the ASD relay kicks off again and a code is set.

Starting issues are tough to track down, particularly if you don't have any codes to help... Best bet is to start with the basics: fuel pressure at the rail when trying to start should be 49 psi; pull each plug wire individually and hold it near the block to make sure it's sparking; do a compression test. We'll get there eventually...