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Vats system
I had a no crank no start issue and when I did the security light would come on on the dash with the Ignition like normal but then when I got to where I could crank the car and it actually turn over the security light stopped working on the dash altogether and now the fuel pump don't come on and I have no idea what to do
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Re: Vats system
Sounds like the PCM might not be receiving the “fuel enable” signal from the VATS (PASS-KeyII) system.
What year is your car? There are subtle differences in the system, depending on the year of the car. Here's an excellent article on how the PASS-KeyII system works, and troubleshooting it: 4th Gen LT1 F-Body Tech-PassKey/VATS |
Re: Vats system
Originally Posted by Injuneer
(Post 7014536)
Sounds like the PCM might not be receiving the “fuel enable” signal from the VATS (PASS-KeyII) system.
What year is your car? There are subtle differences in the system, depending on the year of the car. Here's an excellent article on how the PASS-KeyII system works, and troubleshooting it: 4th Gen LT1 F-Body Tech-PassKey/VATS |
Re: Vats system
When you say “the SECURITY light stopped working …… altogether” do you mean it no longer lights up even during the 3 second bulb check when you turn the key to “RUN”?
And are you saying the fuel pump no longer primes for two seconds when you turn the key to “RUN”? |
Re: Vats system
Originally Posted by Injuneer
(Post 7014539)
When you say “the SECURITY light stopped working …… altogether” do you mean it no longer lights up even during the 3 second bulb check when you turn the key to “RUN”?
And are you saying the fuel pump no longer primes for two seconds when you turn the key to “RUN”? |
Re: Vats system
Do all the other dash warning lights come on in bulb check? If only the “SECURITY” light is totally inoperative, may be pointing to a problem with the theft deterrent module (DTM). That's what controls the SECURITY light.
But that doesn’t account for the fuel pump not priming. That is controlled by the PCM, at least on the initial turn of the key. After it primes for two seconds and shuts down the PCM is looking for the fuel enable signal from the TDM. It would have to be a partial failure of the TDM because is also sends a ground to the theft deterrent relay (TDR) that enables the starter. http://shbox.com/1/pass_key.jpg It's possible to scan the PCM for the code (DTC 46) that indicates the TDM is not sending the fuel enable system. If it’s a problem with the TDM not sending the fuel enable signal, there is a reasonably priced bypass module that can supply the signal to the PCM. |
Re: Vats system
Originally Posted by Injuneer
(Post 7014541)
Do all the other dash warning lights come on in bulb check? If only the “SECURITY” light is totally inoperative, may be pointing to a problem with the theft deterrent module (DTM). That's what controls the SECURITY light.
But that doesn’t account for the fuel pump not priming. That is controlled by the PCM, at least on the initial turn of the key. After it primes for two seconds and shuts down the PCM is looking for the fuel enable signal from the TDM. It would have to be a partial failure of the TDM because is also sends a ground to the theft deterrent relay (TDR) that enables the starter. http://shbox.com/1/pass_key.jpg It's possible to scan the PCM for the code (DTC 46) that indicates the TDM is not sending the fuel enable system. If it’s a problem with the TDM not sending the fuel enable signal, there is a reasonably priced bypass module that can supply the signal to the PCM. |
Re: Vats system
The PCM will also set a code for a faulty SES light. Time to scan for codes.
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Re: Vats system
Originally Posted by Injuneer
(Post 7014543)
The PCM will also set a code for a faulty SES light. Time to scan for codes.
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Re: Vats system
Any possibility you shorted something and blew a fuse? One of the PCM grounds is on an engine block stud near the starter.
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Re: Vats system
Originally Posted by Injuneer
(Post 7014545)
Any possibility you shorted something and blew a fuse? One of the PCM grounds is on an engine block stud near the starter.
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Re: Vats system
Originally Posted by Injuneer
(Post 7014545)
Any possibility you shorted something and blew a fuse? One of the PCM grounds is on an engine block stud near the starter.
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Re: Vats system
The Shoebox website has tons of info on the LT1:
http://shbox.com/1/g103.jpg From your description, you have no fuel pump (controlled by the PCM, supplies 12 volts to the fuel pump relay signal side) and no spark (controlled by the PCM, supplies 12 volts to the Opti). No SES light (controlled by the PCM). The risk in poking the jack handle at the starter was accidentally connecting 12 volts to the ground stud. Did you get an arc? Did that method cause the starter to function? May have damaged the ground stud, broken the wire, or back-fed the PCM and toasted part of it. You can test the fuel pump by applying 12 volts to the fuel pump prime connector near the PCM: http://shbox.com/1/fuel_pump_prime.jpg The PCM has four 12 volt power connections. Two of them come from the ignition switch, through fuse #5 in the dash panel. Two of them are supplied direct from the battery, from a fusible link attached to the red plastic battery "+" box, then through fuse #8 in the under hood box. Did you check the fusible link? http://shbox.com/1/1995_pcm3.jpg |
Re: Vats system
Originally Posted by Injuneer
(Post 7014558)
The Shoebox website has tons of info on the LT1:
http://shbox.com/1/g103.jpg From your description, you have no fuel pump (controlled by the PCM, supplies 12 volts to the fuel pump relay signal side) and no spark (controlled by the PCM, supplies 12 volts to the Opti). No SES light (controlled by the PCM). The risk in poking the jack handle at the starter was accidentally connecting 12 volts to the ground stud. Did you get an arc? Did that method cause the starter to function? May have damaged the ground stud, broken the wire, or back-fed the PCM and toasted part of it. You can test the fuel pump by applying 12 volts to the fuel pump prime connector near the PCM: http://shbox.com/1/fuel_pump_prime.jpg The PCM has four 12 volt power connections. Two of them come from the ignition switch, through fuse #5 in the dash panel. Two of them are supplied direct from the battery, from a fusible link attached to the red plastic battery "+" box, then through fuse #8 in the under hood box. Did you check the fusible link? http://shbox.com/1/1995_pcm3.jpg |
Re: Vats system
Originally Posted by shayhenderson88
(Post 7014559)
no I never seen or heard a spark happen. But yes the starter did start turning over after that.
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