Camaro350z28

Just got this 95 z. 383 and emissions are ripped out. now i wanna scan the SES light and get all the codes. See which ones were EGR and other stuff taken out related. But i also wanted to make sure everything else was fine. no o2 or maf codes stuff of that nature.

well i go to schucks, get the scanner.. hook up obd1 scanner to my obd2 connector, key on, it takes like 60 seconds and tells me it cannot connect to read the codes. i tried 4 times, unplugging and plugging everything in again. what could be my problem? bad pcm or what? thanks

moparman

Check the cig lighter fuse.

Are you absolutely sure you have the right cable? As you noticed, the car is OBDI with an OBDII connector. Somewhere on shoe's site is a pic of how to use jumpers to connect the car's ALDL port to an OBDI scan tool.

Camaro350z28

so it could be a fuse? and i am positive it was right. obd1 scanner with the obd2 cable. i used the same scanner to scan my friends 95 z24. it worked on his car just not on mine. ill check the lighter fuse. thanks

Camaro350z28

fuses are fine. im not sure what else to go with? maybe the pcm is bad?

shoebox

...or you have a connection problem from the DLC to the PCM.

Camaro350z28

so just run through all the wiring? how does is route? does it go from the connect and run through dash then out firewall or out firewall and run underhood?

Injuneer

Go to Shoebox's site, and look at PCM wiring diagram pcm1

http://shbox.com/1/4th_gen_tech2.html#1995_pcm_wiring

Then check his pinout diagrams for the body connectors, to verify the body connectors are the same for your 94 as shown on his 95 wiring diagrams.

Camaro350z28

i see, that is very helpful actually. im gonna have to follow those wires and see whats going on. the only good thing about this is i never have dealt with it. i love to learn new stuff and fix all problems on these cars. thanks for the help guys.

i will update my sig too, just got rid of the vette.

shoebox

Take a digital meter and put the red lead on pin 9 (serial data) and the black on 5 (5 is a ground-so is 4) at the DLC. It should read 4.5v-5v. If your scanner needs no external power, those are the only pins needed to read the PCM.

Camaro350z28

im only getting 2.82 off of that digi meter check.. what does that means? power wire bad or something?

shoebox

Could be the power wire, ground wire or good voltage is not getting out of the PCM or a poor connection along the way.

Check (ohm) the grounds of the DLC to a good ground (like bolts under the steering column). You should get close to zero readings if good.
Measuring pin 9 to ground (volts) should also give you 4.5-5v if ok. I forgot to mention to check the voltage with the key ON. There should not be any voltage with the key OFF.

Camaro350z28

ok ill head out and check all this now.. and ya i did it with the key on.

thanks for the help and your quick responses i have no idea on this electric stuff. i just wanna get my codes and back to making this thing purr ha

Camaro350z28

ok. i ran the number 9 pin and then to a good ground and got the same 2.8... then i ran the number 5 pin ground to my hot wire to my manual fan switch and got 12v... so does that sound like maybe the data lead #9 pin has somethin wrong with it?

shoebox

It's looking that way. You might want to disconnect the PCM and ohm the wire from D30 to the DLC and see what you get.

Camaro350z28

ok i ohm'd the d30 and the 9 pin.. i came up with .8. is that good or bad? sound like its that wire possibly? or the pcm itself? thanks