Pulling Ecu codes

[fwdturbobov1996]

90 awd has a cel now, running really funny. Im reading on vfaq how they check the cel code and was wondering if I didnt have to go buy anything, for the fact that I dont really see how they are making it work, but maybe with the buzzer they use I would see it. Anyone have any other ways except link/logger.

 

[ROOKIE1]

Autoparts stores can check codes . Usually for free .

 

[fwdturbobov1996]

I thought last time I took it there they said they couldnt do it b/c the age of our cars. No obd2

 

[ROOKIE1]

http://dsmtuners.com/forums/forumdisplay.php?f=51 . Try posting for local help here . Regional tuners in mizzou site .

 

[chrisfrye]

Hey i used a voltimeter to read my ecu codes. I'm sure you have a voltimeter lying around, analog is easier to translate but i did it with a digital. If you want a write up on how to do it let me know. Autozone said they couldn't check me ecu codes either!

 

[chrisfrye]

Hey I decided to write up a good way to check your ECU codes with a voltimeter, my search here yeilded nothing.

Firstly, make sure your battery voltage is good, at least 11-12v, your transmission is in neutural and all of your accessories, lights, etc are off. And if you can run it up to normal temp.

Now its better to use an analog over a digital because what your going to be doing is recording(Writting down) the sweeps. Sweeps are a breif 0-12v signal sent in specific pulses to the ecu to display cel codes. Digital you have to try to translate in real time a voltage number into a line, isn't too difficult but you might have to try a little bit to get a code reading.

Your going to want to connect the voltimeter between terminal number 12 and 1 of the "data link" connector. Its underneath the driverside dashboard sitting next to your fuse box.(see Diagram)

"Normal system operation is indicated by Code. No 1, by a single sweep of the needle through a 0-12volt range, repeating constantly. This is exactly the opposite of NO Code when the ecm is faulty and the needle of the voltmeter will remain on 12v and not move at all"
When my ECM was faulty, and when i say faulty i mean my transistors, capacitors and some other components completely melted, it didnt give me a constant reading of 12, instead it threw every code possible, and some that didn't exsist..

So turn your ignition to the ON switch but don't start it.

Try to record the "sweeps"(see diagrams) as you see it. there are short/quick sweeps(go up to 12v and right back down), longer sweeps(will take longer to get up to 12vand and go back down), short pauses( which really arent pauses but look like it on the graph, pretty much a sweep immediatley followed by another sweep. and longer pauses which will read nothing for a second or so (in between)before another sweep.

If your throwing more then one code, there will be a short pause interval and then onto the next code(they're displayed in numerical order according to the number of sweeps in a code set)
You need to watch for this as it makes it very difficult to decifer codes if you didnt mark where the next one begins and ends. A good way to tell when a new code starts is when the longer sweeps start after a series of quick sweeps.

At the end of all of your codes there will be another pause and then repeats it all.
It took me a little while to get the hang of recording the sweeps from a digital, but practice makes perfect haha.

EXAMPLE,
You get two slow sweeps, pause, then 3 quick sweeps.
long interval pause, four slow sweeps, pause, then 2 quick sweeps.

You threw codes 23, and codes 42.

I'm not the best at writting up how-to's, or making graphics(i'm sorry for the graphics my linux pc was down and all my windows had was crappy Paintbrush), but i hope this helps
anyone trying to check their ecu codes. let me know if you have more questions.

BTW this applies to 1G 2.0, i don't know about 2g's. I have the code sheet for the 1g 1.8l too if anyone ever needs it, pm me.


EDIT: I messed up the picture on the access port(down a little bit), sorry! heres corrected

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[chrisfrye]

haha vfaq! yeah they do have a good idea with the cheap electric buzzer
http://www.vfaq.com/mods/wayback/BradBauer/electrical/code.html

i also found a light set up
http://www.dsm.org/archives/1998/09/19980907.txt/23.html

they're all the same. probably can get either one for under 5 bucks. I just happened to have a voltimeter. There always good investments. Good Luck!

 

[talonturbotsi94]

The best way would be trying to find a local dsm guy with a 1g data logger to help you read the codes.

Also just so ya'll know at autozone they can only check obd2 cars with there tester unless its a ford or a chevy.

 

[fwdturbobov1996]

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Now I have prongs 1 and 12, but am missing others. Is this normal? Also what setting do I have teh volitmeter on. I had it on the 12v at the bottom and all it does is throw numbers from 0-4 or something. I have the red wire hooked up to pin 1, the black to 12.

 

[Rex2342]

You'll need an analog meter not a digital one. You have to be able to read the needles movement to see the codes. Just go to radioShack and pick up the buzzer (part #273-055) and some small aligator clips. It should cost less than $5.

 

[fwdturbobov1996]

ok I think the code is 41, which would be a fuel injector. The buzzer was kind of funny. For the first few seconds it just made a series of weird noises, would go high then low pitch within the same buzz. It then kept sending out the same code a long,long,long,long then short buzz, then repeated it.

 

[fwdturbobov1996]

Fixed, clip on one of the injectors was half way on, pushed it down, boom. Idles fine. Thanks for the help everyone. I love tuners

 

[chrisfrye]

Awesome man good to hear!

You'll need an analog meter not a digital one. You have to be able to read the needles movement to see the codes.

You can definitely use a digital i've done it several times, instead of seeing the sweep of the analog you can translate the digital going up to 12v a sweep easy enoguh

BTW switch it to DC20v