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Old 12-12-2014, 07:51 PM   #1
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Default P0620 CODE QUESTION

Hi, is me again with another problem haha, i think is becoming a hobby for me to repair things in my old impala ls 2000.

anyway, i was reading the thread for the code but i have some questions.

first the problem:

the problem is not permanent, it appears and dissapears when you are driving, and stays if you are driving slow or you are in a traffic jam, sometimes the battery just dies when you are driving (obviously the generator is not working when that happens).

as i know the current generator of the car has been reconstructed several times.

Now the questions:

what should i do?, do i need a TECH 2 to scan how the generator is working? how can i inspect the connections to the PCM and the generator harness?.

im asking cause i dont really trust mechanics here, you guys have solved me more problems than anyone here.

thanks in advance.

also the ABS and trac off lights stays on when the battery is low in charge cause the generator is not working.
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Old 12-12-2014, 08:34 PM   #2
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Do you have access to a multimeter? If so, measure the output of the alternator at the battery cable post on the back of the alternator. Note the voltage, now, take a measurement directly on the battery. Come back and show us what you have.
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Old 12-12-2014, 11:00 PM   #3
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Check your alternator connector for loose terminal fit and or broken wires. As Mike suggested have a meter hooked up on volts settings and move your wiring around and watch for your readings.
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Old 12-12-2014, 11:11 PM   #4
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ok will do it.

if i remember well some of the cables that connect to the alternator looks kinda bad "you can actually see the copper".
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Old 12-14-2014, 05:04 PM   #5
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looks like the problem is on the wiring to the alternator, when its working the volts are ok, but when you move the cables (the ones conected to the alternator) it shuts down and the red battery light appears, also they get hot, when they do the alternator stop working too.

im going to replace the cables, but im seriusly thinking about buying a new alternator.
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Old 12-14-2014, 06:56 PM   #6
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Why replace the alternator? Clearly the cable is the issue at hand.
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Old 12-14-2014, 07:50 PM   #7
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i mean in the future, right now im just going to replace the cables, i will update when i get it done, hope it works
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Old 12-16-2014, 03:41 PM   #8
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bad news, i replaced the cables, and even used a new battery...the alternator gets hot then stops working.

shouldi consider to replace it? i still get the same code on the scanner.
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Old 12-16-2014, 06:29 PM   #9
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Regardless of new, I like to ensure that a battery passes a load test.
I think another alt would be the next logical easiest step, and hope that brings an end to chasing the gremlins.
I did find this interesting though...
https://www.gmforum.com/obd-ii-troub.../p0620-286004/
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Old 12-17-2014, 10:37 PM   #10
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Quote:
Originally Posted by Soft Ride View Post
Regardless of new, I like to ensure that a battery passes a load test.
I think another alt would be the next logical easiest step, and hope that brings an end to chasing the gremlins.
I did find this interesting though...
https://www.gmforum.com/obd-ii-troub.../p0620-286004/
yup it can hold it, looks like the problem is that the copper wires inside the alternator is bad, one of the sides hold more charge than the other, then it gets hot and stop working.

they said i could repair that, but being honest they recomended to buy a new alternator.

which brand should i buy? AC DELCO? DELPHI? BOSCH? REMY?.

rockauto have lot of models.
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