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P1637 Generator L-Terminal circuit

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Old Nov 22, 2010 | 08:22 PM
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Question P1637 Generator L-Terminal circuit

Please Help ... At the moment I have a 3800lbs paperweight sitting in my garage.

Originally Posted by Mike454SS

P1637 though is the alternator...possibly some damage to it's wiring, or possibly something wrong with the alternator, or it could be the wrong alternator for the car.
Originally Posted by 2001NBMZ28
Check the exciter (red) wire/connection at the alternator. Also check the voltage at the battery with the car off and running.
Originally Posted by WS6 Rampage
BTW,.. Just a bit more info on my issue. (P1637 code) ... Battery has a charge. All the lights for the gauge cluster still light up, alarm works & headlamps raise and lower at normal speed. .... I can't hear the starter 'click' when I turn the key. .... Starter Fuse isn't blown... SHE JUST WON'T START!
Originally Posted by WS6 Rampage
Update: ... Removed the alternator and battery today. Took them to Autozone for testing. Both in good shape. Went down to the dealer, bought an exciter wire ($54.40!!!) and cut and spliced it in.... CAR STILL WON'T START!!! ... Still throwing the same damn code too (P1637) ... God Damit!!!!
(Original Thread)
https://ls1tech.com/forums/pcm-diagn...7-how-fix.html

My builder/friend says he thinks it a relay and will pop over to my house and check it when he can free up some time but I just wanted to hear what other people's thoughts were.

..... (the starter is only a year old) I checked the starter visually. The purple wire seems unscaved... Starter doesn't seem to have any visual damage. I'm stumped!
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Old Nov 23, 2010 | 08:54 PM
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a code 1637 has nothing to do with the car being able to start

do you have power at the small wire at the starter when you crank the key,, if yes and the battery os fully charged then the starter is bad,

if you have no power at the small wire at the starter when you crank the key,, then its probly your vats system,, this is easy to bypass,, just do a search for vats bypass
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Old Nov 28, 2010 | 07:44 PM
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What he said above.......
I have always had that code. Car runs fine.
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Old Nov 28, 2010 | 10:01 PM
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If I remember correctly, I also have a security system code come up as well. I'm not sure if it's related but it wouldn't surprise me if it was. ... I'm gonna plug into my OBDII real quick and find out exactly what code it is.
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Old Nov 28, 2010 | 10:38 PM
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K.... So the other code is P1626 Theft Deterrent Fuel Enable Signal Not Received / (VATS)... Anyone know of a good "step-by-step" for the starter relay bypass?
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Old Nov 29, 2010 | 04:58 PM
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Found this:
VATS bypass module. ..... Thoughts?

http://www.youtube.com/watch?v=8QNhY...e_gdata_player
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Old Nov 29, 2010 | 07:12 PM
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Oh, ... I should have just asked this first.

... So is there a chance that a tuner could fix this issue? Is there a chance that the VATS can be re-enabled on its own after being tuned out once before? ... I ask because I THOUGHT I asked my tuner to delete the VATS originally but I either might have forgot (very possible) or he might have forgot.
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Old Nov 29, 2010 | 09:11 PM
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Originally Posted by WS6 Rampage
Oh, ... I should have just asked this first.

... So is there a chance that a tuner could fix this issue? Is there a chance that the VATS can be re-enabled on its own after being tuned out once before? ... I ask because I THOUGHT I asked my tuner to delete the VATS originally but I either might have forgot (very possible) or he might have forgot.
No, the VATS won't re-enable by itself if removed from tune. I have removed it to a few daily driven cars and now VATS is a forgotten issue
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Old Nov 29, 2010 | 09:43 PM
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Originally Posted by MontecarloDrag
No, the VATS won't re-enable by itself if removed from tune. I have removed it to a few daily driven cars and now VATS is a forgotten issue
K... See, that's what my issue must be then. ... I called my tuner earlier. I just need to take the PCM out of the car and have them play with it again.
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Old Nov 30, 2010 | 02:24 PM
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If VATS is turned off in the PCM only, that will ONLY prevent it from disabling fuel, and it WILL NOT prevent it from interrupting the starter. The starter is NOT part of the PCM loop on a 4th gen. If you take the PCM out of the car completely, you can still make it crank, it just will never be able to actually run without it

In order to prevent it from interrupting the starter, you can bypass the VATS relay, which will still result in a security light on your dash, OR you can measure the resistance of your OEM key, and then put a resistor of the same resistance into the vats harness in the collum after disconnecting it from the ignition cylinder...this will get rid of the light show on the dashboard, and will allow the car to start, and then the way the PCM is programmed won't matter.

Originally Posted by jay_lt4
do you have power at the small wire at the starter when you crank the key,, if yes and the battery os fully charged then the starter is bad
...or the large battery cable to the starter is damaged/broken/corroded/not connected properly
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Old Dec 2, 2010 | 11:09 PM
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K... VATS was still on. Tuner turned it off. ... Car still won't start!!!.. The only thing different is that it's not pop'n any code right now.


... If I go down to the dealer and order a new key, will this help?... I need a spare key anyways!

Last edited by WS6 Rampage; Dec 2, 2010 at 11:15 PM.
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Old Dec 5, 2010 | 08:46 PM
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Try cleaning the key first. Then follow the suggestion about a manual bypass with resistor in the key circuitry to eliminate the key socket and column wiring

Chris
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Old Dec 6, 2010 | 01:41 AM
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Originally Posted by Rocko350
Try cleaning the key first. Then follow the suggestion about a manual bypass with resistor in the key circuitry to eliminate the key socket and column wiring

Chris
Problem Solved! ...
https://ls1tech.com/forums/general-m...how-video.html
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