2000 LS PATs/PCM/Key issue?? plus dealership nightmare

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thenorthface

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Hi everyone, thanks for reading...this might get a little long...

I have a 2000 LS that intermittent issues recognizing my key and starting the car...half the time i put the key in the ignition turn to the on position the car recognizes the key and starts up...the other half of the time i put the key in the ignition and turn to the on position and the security like blinks rapidly and the car will crank but wont turn over...was told by the dealer this is the PATS security system and the issue could be my key needs to be reprogrammed and that i need a 2nd key anyways and should have this done, or the PCM module is malfunctioning...i do some google research and hear that aftermarket alarm/remote starts can bypass this and fix my problem, but every place i call and talk to(best buy and some local car audio places) tell me this is impossible, one of the guys says he thinks the most likely cause is the antenna in the ignition lock cylinder that reads the key's code and sends it to the PATS/PCM...

well i take the car to the dealership and have them cut and reprogram my keys and they call saying the car shut off and went into theft mode...they cant restart it, we unable to reprogram the keys and just have to wait for the system to reset...ok whatever, i leave and tell them to call when its ready...

so they call me back, they got the car started and reprogrammed the keys, so i come back to pick the car up and pay for the keys... and it wont start and the PATS is locking me out...they dont know whats going on, said they got it started 3 times before i came in and that it is just a waiting game again...fine, i tell them to run a diagnostic to see if the PCM is bad and needs replaced and ask how much it is, their tech guy is on lunch so itll be at least an hr before he is back to run the diagnostic and in the meantime they cant quote me a price on how much it will be to replace the PCM until after running the diag(i find this odd, but its kind of besides the point)...i go back to work, ask them to call me if/when they get it started and also as soon as they run the diagnostic to let me know whats wrong and how much its gonna cost...they close @5pm

well they never call me back, at around 430 i call them just to see whats up and the call gets dropped...i get busy and finish up work and get a ride back to the dealership around 5:15ish...my car is sitting out front running with the window down and no one around and the door to the service center locked, no diagnostic report, no note, nothing...im pissed but happy the car is running and its friday so i just decide to take the car and figure it out over the weekend and go back to the dealership on monday...

so anyways i went to autozone today and asked if they could pull any codes that may help and all i got was this:

P0420 Auxiliary Input and Output

i know whoever had the car prior tried to ghetto rig a system and there are some wires hanging in the trunk from the amp and whatnot and the radio works but the display does not, but i am not electronically or mechanically inclined so i have no clue if this could be a source of the problem or what...oh also i dont know if this matters but when i put the key in and engage it to the on position i hear a brief pop from the speakers like a speaker is blown or something right before the PATs recognizes or rejects my key...

anyways thanks if you read all of that and have any input that could help me...
 
I had a very similar problem with my 2000 LS, 3.9 plus a similar experience with the dealership. After having my key recoded, twice, and paying for that, it ran fine for a few days and then completely shut down. It would crank, not crank, not start...then nothing.

Stranded at work, I had the car towed to the dealership and after a few days got a call from the service manager. The problem seemed to be the gauge cluster which included a security system, or part of it. With no other options I told them to replace it...not so fast, seems the gauge cluster is not in production and the only option was a salvaged part. Fine, $600 later the car was fixed, not to mention the dealership broke my hood release and after the transplant my clock spring malfunctioned.

Good luck to you, I hope this helps in some way, it could be the lock tumbler, a faulty wiring issue...or who knows.
 
thenorthface said:
...P0420 Auxiliary Input and Output...
Click to expand...

P0420 is Catalyst System Efficiency Below Threshold Bank 1

You probably have or had bad COPs (Coil On Plug) and this has damaged your catalytic converter(s).

The PATS issue is most likely the antenna or the cluster (the cluster is where the PATS module is). It is 99.99% certain that it is not your PCM. You can be more certain by counting out the two digit PATS error code from the PATS light. The next time it flashes rapidly, just leave the key on. After a while the rapid flash will stop and then it will flash out a two digit code a few times.
 
joegr said:
P0420 is Catalyst System Efficiency Below Threshold Bank 1

You probably have or had bad COPs (Coil On Plug) and this has damaged your catalytic converter(s).

The PATS issue is most likely the antenna or the cluster (the cluster is where the PATS module is). It is 99.99% certain that it is not your PCM. You can be more certain by counting out the two digit PATS error code from the PATS light. The next time it flashes rapidly, just leave the key on. After a while the rapid flash will stop and then it will flash out a two digit code a few times.
Click to expand...

yes sorry, i wrote the wrong code, when i acquired the car i was told the right side cat converter needed replaced soon...so that code did come up...the other code i got was p1633 which the autozone guy said was aux input and output...but upon some googling it seems it is the keep alive memory...which is related to battery voltage?

interestingly enough i had a car audio place pull all the non-factory and aftermarket wires that were hanging from the amp in the trunk, and they also cleaned the battery terminals and buffed out the ground connection and tightened down all the connections...and the car ran perfect for about 2 whole days, car would turn over everytime no problems, and i drove it around a lot just waiting for it to happen...well finally tonight i stopped at the gas station, filled up, hopped back in and boom it wont turn over light is blinking, i pull the key put it back in and it recognizes it again and i drive home, in my driveway its about 1 out of 3 times it doesnt recognize it...

so its looking like a battery connection problem perhaps? i guess ill try again tomorrow...
 
I had this issue recently and it was my fault from leaving a code scanner plugged into the obdII port.

It kept tripping the pats system and wouldint let the car start.
 
ok also, just went out and got the PATS code, the light blinked once, then paused, then 6 times...so i guess the PATS error code is 16?
 
Check the relay...you can just swap one that isnt used much (heated wiper) and swap it with the pcm relay.
 
I would check it since it doesn't cost anything..

What's up with the name? Look at your sweatshirt and say 'that would make a good username'.. lol
 
BlackLS06 said:
Check the relay...you can just swap one that isnt used much (heated wiper) and swap it with the pcm relay.
Click to expand...

im pretty much useless at things like this...but from what i can tell from the owners manual im swapping relay 12(heated wipers) with relay 14(PCM Power)?

do i need to disconnect the battery before doing this so i dont electrocute myself? lol
 
FASTLLS said:
I would check it since it doesn't cost anything..

What's up with the name? Look at your sweatshirt and say 'that would make a good username'.. lol
Click to expand...

lol basically, i needed to register to post and ask some ?s and use the search function, so i was scrambling for a username and bingo :)
 
That sounds right to me.

I have an 06 but the relay numbers sound the same,

I disconnected mine just to reset things and just in case.
 
also just wanted to say thank you to everyone that has replied so far...has been uber helpful already...and really cool of you guys to tolerate my questions and inquiries.
 
ok, so now im weirded out and dont wanna mess with anything...strange wire coming out of the PCM relay and other spots in the fuse box...no clue if this is normal or wtf the previous owner was doing here...?

probably just gonna wait til the AM and take it somewhere and have it looked at...

IMAG0005.jpg
 
That might be your problem.

Those wires should not be there.

And sad that the dealer did not catch this either.

Looks like power is being slaved from there to something which could be jacking with the pcm and giving you hard starts.
 
is it safe for me to remove the relay with the wire in it move it to the heated wiper slot and vice versa?
 
That i cant say all i know is there should be no wires under that cover.
 
well i just went and changed them...5 or 6 tries and couldnt replicate the PATs error...when i went to pull the PATs code 16 earlier it only took one try...guess we'll wait and see...
 
thenorthface said:
well i just went and changed them...5 or 6 tries and couldnt replicate the PATs error...when i went to pull the PATs code 16 earlier it only took one try...guess we'll wait and see...
Click to expand...

It makes sense that the add on wire could be causing poor contact. PATS code 16 fits with P1633. P1633 is "Keep Alive Power Voltage Too Low."

I am again disturbed that the dealer couldn't figure this one out as soon as he read the codes and saw the added wires.
 
small update, the problem seemed solved for about a day and a half, happened again today and i was able to replicate it in my driveway but in a much lower frequency than usual...one thing i have noticed and wasnt sure if it was normal or not (only had the car for about a week now...) was that the cooling fan seems to run all the time esp when the car is idle and will run after the car is shut off...it will then shut off and then start running again for a short period of time while the car is OFF...i followed the wires in the fuse box pictured above and they lead to a ground and also to what looks like the fan and a small circular object mounted on the back of the radiator...not sure what the explanation on this is...but the fact that it continues running after the car is shut off makes me wonder if its affecting the battery voltage or something? had the battery tested at autozone today, they said it was great...when the car doesnt start the error code is still 16...so back to the drawing board i guess.
 
Your 2000 LS came from the factory with a hydraulic fan. Someone has converted yours to aftermarket electric.

I would suspect that you have some damage to the socket that the PCM relay goes in at the least. You may well have some other electrical problems due to the alterations done. You need to find a good shop that specializes in car electrical repair. A dealer probably wouldn't be able to help without spending a fortune to put it back to stock configuration first.
 
joegr said:
Your 2000 LS came from the factory with a hydraulic fan. Someone has converted yours to aftermarket electric.

I would suspect that you have some damage to the socket that the PCM relay goes in at the least. You may well have some other electrical problems due to the alterations done. You need to find a good shop that specializes in car electrical repair. A dealer probably wouldn't be able to help without spending a fortune to put it back to stock configuration first.
Click to expand...

was pretty much thinking the same thing...here is a list of electrical issues with the car...

-radio works but no LED display
-stock amp and sub make a "pop" when the car is turned on or off
-lights on the gear shifter work sporadically turning on or off if i "jiggle" the shifter
-aftermarket(?) cooling fan running more than usual

also AC blows hot but this does not seem like an electrical issue...?
 
add to that list no trunk or under the hood illumination...could be bulbs or fuses tho...lol
 
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