1999 pontiac grand am not charging
I have a 1999 pontian grand am se 2.4l that is not charging fusible links and fuses are good and a brand new alternator has a u1000 code a u1064 and p0562 code
Cars & Trucks
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Answers & Comments
Diagnostic Test Code (DTC) U1000 has a generic description of "Class 2 Serial Data Link Malfunction".
DTC U1064 has a description of "Loss Of Communication With Body Control Module (BCM)"
These codes can be caused by a malfunctioning charging system and should be ignored for now.
DTC P0562 has a description of "System Voltage Low". So this code basicly is only verifying that you indeed have a no-charging problem and that the other codes are most likely also caused by low system voltage.
Although these codes do verify that you have a charging system problem, they are useless in finding out exactly what is wrong with your charging system.
You will need a scan tool that is capable of 2-way communications with the PCM and performing system tests. you will also need a digital multimeter to test the system as you command the generator circuits on with the scanner. If your scanner can do this, let me know and I will get you the troubleshooting instructions for your vehicle. Otherwise, you will have to take it to someone who is properly equipped to diagnose your charging system.
Did you disconnect the alternator connector and check for voltage at the RED "L" wire while commanding the generator on? If battery voltage is not present at the "L" terminal when you do this, then check for an open circuit between the PCM and the "L" terminal at the alternator. (Connector C1, Pin 74 at the PCM) If an open circuit is found, repair as necessary and retest the charging system.
Note that GM vehicles are notorious for loose/corroded pins at the PCM. (I have fixed many problems by simply cleaning the connectors with contact cleaner and applying a thin coat of dielectric grease to the pins and plugging them back in.)
If no problems are found on the RED wire (and cleaning the PCM pins does not work) replace the PCM.