ttopvincent

I have a 94 z28 ttop with the lt1. as you know you have to have the fuse working for the cigarette lighter to diagnose your car. everytime i put a fuse my horn honks then the fuse pops. what can be the problem? i need to plug in the obd and see why im having an ses issue

Injuneer

For starters there is no 12V pin in the 94's OBD-1 ALDL connector, so there is no connection to the cig lighter circuit. The fuse has nothing to do with the ability to scan the PCM.

Appears the problek is the horn circuit - could be a stuck horn relay, shorted wire or the switch in the steering wheel. Shoebox has the horn wiring diagram on his website but it's for a 95 which does have a 12V pin.

ttopvincent

when I plug in the obd nothing happens. like there is no power getting to the plug


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Injuneer

What scanner are you using?

ttopvincent

don't remember the name off the top of my head but you can buy it at auto zone. it says 94 camaro on the box


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shoebox

That's not much to go on. Most OBD-I scanners don't need any external power.

ttopvincent

my cousin plugged it in his truck and his sea light flashed the code. did my z28 and it did nothing. I'm kinda new to this so maybe I'm doing something wrong


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shoebox

You cannot flash codes on a 1994 LT1. If you are using a device that merely plugs into the DLC and shorts the pins (something you could do with a paper clip) and has no readout, that won't work. You need a real scanner.

Injuneer

You were probably using the Actron CP9001.



Yes, it says on the box that it works with a 94. If you look at the 94 factory shop manual, it suggests that you may be able to pull the codes by shorting the ALDL pins (the Actron is a $30 substitute for a penny paper clip, as mentioned above). Both are incorrect, as Rob points out. 1993 was the last year of the LT1 ECM that you could flash the codes by shorting the pins.

You can also get free (limited to 20 uses) scanning software that will pull codes, from TTS DataMaster. Just need a cable for a laptop. There is also (not exactly)FreeScan, which used to be free but now has a small charge to cover the cost of updating it to more contemporary PC operating systems.

ttopvincent

so I can't use the actron? what would be my best route?


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Injuneer

As already mentioned by 2 of us, the Actron CP9001 or any device that shorts the ALDL pins will not work on your car.

As already mentioned, scanning software is available - DataMaster or FreeScan.

You could also use an Actron CP 9145 with the OBD-1 optional cable. There is an older Auto X-Ray that works fine. Maybe Rob can advise on the part number for that one. You could find a Scanmaster LT1, used. I have one and it's great for not only pulling codes, but for allowing you to monitor about 20 different sensors and PCM parameters real time.

http://www.injuneer.com/images/photo.../DCP04287a.jpg

ttopvincent

ill look into the actron cp 9145 and the auto x-ray. thank you guys. like i said before i am completely new to these vehicles so have patients.