rebelyell

yeah... I plugged in a code scanner tool into the OBDII diagnostic port and the reader gave me an error and said it was unable to connect to the car...

any ideas on what could be causing this?

BadBandit69

iTrader: (13)

I could be WAY off base here but this happened to a friend of mine with an lt1 car. And I think the problem was a blown cig. lighter fuse. I no I no it sounds dumb but thats whats coming to me, and isn't hard to check.

rebelyell

lmfao... my buddy just told me the same thing... only GM...

Ed Wright

iTrader: (1)

If the scanner would not power up, that would be the fuse. If it powers up, the fuse is OK, the problem is normlly the connector needing cleaned.

Schwanke Engines

iTrader: (1)

yep, cig fuse.

Ed Wright

iTrader: (1)

If the fuse is blown, the scanner won't give an error message, simply won't power up. Blown fues = no power to the scanner. Won't turn on.

rebelyell

the connector really aint gunked up... any ideas?

nemss1

may wanna check the wires to the splice pack

racecar

First, Check all fuses.

Ed Wright

iTrader: (1)

It doesn't have to look "gunked up". Our '95 Camaro r&d car needs it cleaned about half the time the Tech2 is plugged in. Many older cars do that. Spray some brake parts cleaner, TV tuner cleaner, etc, in the connector and plug & unplug the scanner several times. Gently blow the excess cleaner out, and try it. I see that all the time. If the scanner powers up and the car will start, it ain't gonna be a fuse.

Good luck, Ed

C_Rules

iTrader: (7)

im having the same exact problem with my 94 LT1. i get a cant connect the pcm error message. this is stopping me from uploading new tunes.

so brake parts cleaner is sfae to use on the cable and my obd1 port?

Ed Wright

iTrader: (1)

No problem using it for that. Hold a shop towel under the port and don't spray a lot. I don't know what it would do it the dye in the carpet, probably won't help it. I've used it for that a lot. If you have go buy something, NAPA has a spray Electronic Contact Cleaner which may be better.

C_Rules

iTrader: (7)

sprayed it and still nothing. can't connect to the pcm. any other ideas? problem with the harness?

C_Rules

iTrader: (7)

anybody else got anyideas with this. the port still isnt wokring. ive tried swapping pcms, using a different scanner, spraying the ports with cleaner and nothing. car is running like crap when it wasnt before. could it be that i had some type of short which fried a couple of things?

Ed Wright

iTrader: (1)

Got me. What kind of scanners are you trying to use? Sounds like maybe a wiring problem.

C_Rules

iTrader: (7)

i was using my laptop with datamaster. then i had my mechanic try to use his obd1 scanner (not sure of the name). i dont know what happened but here is a list of the events:

1) hooked up my latptop to the car and logged it for like 20 minutes
2) came home turned it off and looked over the log
3) made some changes to the tune, went to hit program pcm button but by mistake hit change vin. i canceled out of that and tried to upload a tune and there was no communication between the pcm and the my laptop
4) tried to turn on the car and it wouldnt
5) tried a different pcm and the car didnt turn on but the fans now turned on with the switch engaged
6) swapped back to the old ecm but fans were still coming on
7) had my mechanic come over turns out my fuel pump relay (inside the car by kick pannel) wires were damaged
8) fixed the wires, car turns on and runs, but the service engine light is on, has no low power under 2K, idles high and is running pig rich.

Draconislivida

Check this out, may offer some help.

https://ls1tech.com/forums/pcm-diagn...l#post12220602

Ed Wright

iTrader: (1)

Don't ever stop one from programming. You probably corrupted the PCM, and it may or may not be recoverable without pulling the chips, reflashing them, then soldering them back in. Also, the fans running all the time tells you it's likely the PCM. Some times you can recover one on the bench if you have a bench-top harness, when you can't do it in the car.

Btw guys, the 1994 F body does not have an OBD2-style connector, which means it won't be a fuse.

Don't ever "cancell out" once you start programming one.

C_Rules

iTrader: (7)

i went to hit the program button but hit the change vin accidentally. then the make sure switch is on box popped up. That box has the ok and a cancel option. So i hit cancel the computer had not started to reflash or program yet. I tried another pcm and no luck either. my mechanic went thorugh the harness and said it was fine and i should try another pcm. i was a ble to get a third one to see if it will communicate.

C_Rules

iTrader: (7)

well third times a charm new pcm works and communicates.

little weird thing though. when my original pcm wouldn't communicate the fans wouldn't turn on. bought another one and as soon as i turned the car on the fans would turn back on. when i put the original back and it started turning the fans on too. weird wasn't doing that until i put in the other one.