I'm replacing my PCM in my 1995 5.2L V8 Limited today and was wondering if I need to flash the new computer or not? There is no sticker on my old one saying I need to and the instructions that came with the new one said "you may need to". I've been 3 weeks without my ZJ and I need this thing to run so I'm hoping for plug and play!
Also is there any re-learn process or anything else? I plan on testing the voltages on my old PCM to confirm that it is dead then disconnecting the negative terminal on the battery then pop in the new PCM reconnect the battery and start it up. If it doesn't work the thunder storms tonight will put out the flames...
Anytime you disconnect a battery cable your electronics will reset. Which means that there will be a relearning process but that just means you start it and let it idle for a few minutes when you reconnect the battery.
1995 should have 1, its located in front of the cat. The wires should lead up over the transmission. Just follow the wires and look for any breaks or burns. Also look for any other wire problems. Again im not for sure its your problem but cant hurt to look. Another possibility is your grounds,.check for loose or rusty conections
do you know where the grounds are located in a 5.2L V8 because I can only find locations for the 4.0L I6 online unless they are the same? Sorry for all the questions this is my first vehicle and I'm learning steadily. Hope this rain lets up after school tomorrow so I can actually check everything -.-
If your going to spend any money on a manual, get a downloadable FSM online.
The paperback toilet paper they sell in part stores are crap. For getting wiring diagrams and other specific info you'll need the factory manual. (10-15 $)
I read some of your previous threads to get some history and you asked about an aux backup light. Did you install it? Where did you hook it up?
You could overload a circuit if it's not on it's own system and blown out a needed fuse for the rest of the vehicle.
The power source for the relays ASD, fuel pump etc. comes from the PCM (5v, 8v). Check the gnds and battery connections like Zee said and recheck all of the fuses.
Here is the PCM connector diagram so you can back probe it with a meter.