I have a 89 Firebird and have a 53 trouble code. The car will crank and I was wondering how to test the key and were I would find what ohm key I need? I'm hoping it's as simple as running the VIN as far as getting a new key. I would like to be able to test the one I have to insure that is the issue. Thanks

 

Do a quick search for VATS and you will find hundreds of threads, many with references and links.
Sorry, you can't find out what key resistance you need from your VIN (thieves could do the same and that would defeat the purpose of the anti-thelf system).

If you have the original key, the new one can be matched to it easily.

 

Measure the Resistance across the pellet in the key.
buy a blank here
http://www.ebay.com/itm/1989-2002-CA...306182&vxp=mtr

 

Hi Ringo234,
To answer you it is reading .518 ohms

 

Ringo234, From what I understand so far is I am getting a signal to the start relay because the car will crank. The key diod is reading .518 to .520 ohms. Not sure I'm getting a signal to the ECM any ideas. I have changed the sending unit and pump. I have reset the ECM codes by unplugging the battery. At that point the car will crank, the injectors will squirt three pulse times and that it back to square one. It's driving me nuts

 

That would point to a shorted/bad pellet key. Half an ohm is likely the resistance of just the leads and probes.

Unless you were reading kilo-ohms and the value on the display is then 518 ohms. That would indicate that you have a key #2 (from the eBay link).

 

If the injectors spray fuel then your key is good and VATS is allowing the ECM to provide fuel for the engine. Why it does not start, is not a VATS problem then.
Have you tried the basics, such as checking for spark? Or spraying more fuel (such as carb cleaner) into the intake to see whether the engine fires up?

 

is the meter set to x1000Ω or x1Ω because .518Ω is practically no resistance at all.
The web sight says .523 but pretty sure they meant 523Ω. Oh and if the car cranks over it is not the key. If your injectors spray it's not a VATS problem.
FYI it is a resistor and not a diode.

 

Yes I was reading it in Killo ohms. The injectors only pulse three times before it throws the 53 code. At that point I have nothing. It will still crank but the injector stop squirting. The leads on my blue point read 0 when touched together, I don't think it the leads. The is showing .518 kilo ohms of resistance. It still doesn't explain why it's throwing the 53 code. Unless it the wrong key resistance. I'm beginning to think the guy who butchered this thing to begin with should have just crushed it.

 

The meter is set at 0.L K ohms.

 

He's right about Ebay but do a search. I bought mine for less than 10 bucks with free shipping. I took it to Wal-Mart and they cut it free of charge. Works like a charm.

 

Pretty sure if the resistance of the key was wrong the car wouldn't crank at all. I do not know much about the VATS system. I did the resistor trick years ago, and when i got a new chip burned I had it programed out. I do remember something about a separate VATS module between the key and the ECM maybe that went bad.

 

So if it's not the key what keeps throwing the code? Every time it's the same code and the same issue. I turn on the ignition, wait for the pump relay to click, crank the starter. The injectors spray three times, it fires and after that nothing. I can crank on it all day and as long as I am dumping fuel in the throttle body it runs. But no injector pulse. Disconnect the bat to reset the ECM and it's the same thing every time, a 53 code. Anti theft control light comes on and stays on even while cranking. I've been reading posts for days until yesterday I decided to ask my self. Thanks for the info but so far it going no ware. Every thing is new other than the ECM and that about to go out the window as well.

 

My 90 camaro FSM says that a 53 is system overvoltage. It means the ECM measured over 17V for 2 seconds. Check your charging system voltage. At any rate, a bad key would be no cranking at all.

 

check this thread. they also had code 53
https://www.thirdgen.org/forums/dfi-...e-53-dont.html

 

That was a helpful thread thanks ringo234. I'm looking into the distributor as far as testing. I posted another thread just a few moments ago. Maybe when you get back online you could check it out. Thanks again for the help.