alternator on 2001 suburban quits working

Battery has a full charge and battery cables/connections, positive and negative, all good?Maybe the generator is faulty? Note the generator wiring diagram. Check applicable trouble codes for generator, I saw several listed. The codes are manufacturer specific codes. To check codes, yourself, at the least, you need an obd 2 code reader that will work with your vehicle and read manufacturer specific codes. Have you done any testing at generator bat terminal? That terminal is hot all the time, even with key off. Use a test light, key off. is the bat terminal hot? If it isn't, something wrong with that wiring circuit. With engine running, you can check charge at that same terminal. You may need to turn on accessory to put more of a load on it.

GA, thks for your response. This is a strange acting issue. It started when the volt gage began to drop and finally the batt light came on. I replaced the alternator because it was quite old. The system worked okay for about a week and started it again. I cleaned the batt neg connections and some grds on the engine block, doubled checked all and the system worked okay for a couple of weeks. Then one night as the engine was idling, the volt meter started dropping down to 12 vdc and lower, the batt light came on; increasing the engine speed did not help. In just a few minutes, the headlights dimmed and the engine just died. There was not sufficient power to raise the open windows. I got a tow to the house and the driver jumped the battery so I could close the windows. Just for kicks, tried to start the engine and it fired right up, with alternator charging, voltmeter indicating 14.2 volts. Removed the jumper cables and the engine started right up again. Let the Suburban sit overnight and it started right up with no jumper cables or charging the battery. The voltmeter indicated the alternator working and the batt lamp off. I replaced the battery anyway; it was 18 months old and I know that batteries can do strange things. It has worked the last several days until yesterday when the voltmeter started dropping and the batt lamp came on. I stopped the engine and restarted, didn't do anything else. The voltmeter showed 14.3. volts, the batt lamp off and the system has worked okay for the past two days. I have a long background on Cat equipment so I am not an novice; just not up on auto systems. This one really has me puzzled.

Cat man Al post: Issues with alternator on 2001 Chevrolet Suburban. • At initial crank and engine running, the rebuilt alternator output was near 14.6 volts and operated apparently properly for some 20 minutes. After this initial period, the voltage would drop off and become unstable. It would even drop to near 9 volts and turn the red charging lamp on • In the process of elimination, these items were done: o Took the rebuilt alternator to the parts house to have it checked for proper operation. Nothing was found to be working incorrectly by the parts technician. o Removed the alternator harness and checked. It was okay. o Replaced the serpentine belt. It was not new and did not look bad but replaced anyway. o Replaced the battery. It was at about half life and checked okay. But damaged cells can do weird things o Removed the battery cables, the positive junction connector on the left side of the cylinder. Cleaned and brightened these all up to ensure good metal connection. o Removed the ECM on the left side of engine compartment. The connector was pristine. There appeared to be no issues with this connector so it was reinstalled. In doing research on the internet forums, I discovered that beginning in year 2000 and 2001, GM had started integrating the engine ECM operating strategy to include some alternator voltage control, ostensibly to reduce the output voltage in order to reduce the load on the engine and improve fuel mileage. The research indicated that the year 2002 model had completed this transition and the alternator voltage now no longer was controlling the alternator voltage output independently of the ECM. I wondered if alternator that I had bought was not compatible with the year 2001 ECM. Researching further, I worked on determining what the part number was of the original alternator on this 2001 Suburban. I found that it was 19244746-a 130 amp alternator. I compared the rebuilt alternator, using the parts store reference information to see if this alternator was identified as a replacement for this original 19244746 part number. I could find no reference that this was the correct replacement rebuilt alternator. I began a search of parts store alternator offerings and found that Advance Auto Parts and Carquest listed a rebuilt alternator (# 8237A) that referenced it as a replacement for the original part number. Advance Auto Parts ---This is 8237A rebuilt alternator was installed on 2001 Suburban on May 30, 2020. It works; it comes up to 14.2 volts and tapers back to 13.9 volts during operation. The initial operation ran well over the 20 minute interval where the other alternator began to reduce voltage and become unsteady. The 8237A alternator regulator does not fight with the ECM over control of the voltage. Output is steady and does not waver or reduce voltage during operation. This is the correct replacement for the original 1924476 alternator. It has now been over one year since installing this 8237A rebuilt alternator. Since installation and first run, this alternator has not had any hint of an operation issue. I am convinced that the charging issue I had was a result of having a rebuilt alternator that was not compatible with the 2001 ECM. I post this because I saw a lot of Suburbans and Tahoes with posts of similar charging issues with no post as to a resolution of the issue. I believe that there can be an incompatibility of some rebuilt alternators for later model vehicles which may be installed on these 2000-2001 models and suffer this incompatibility. At least that is what I found that solved my problem. 2001 Chevrolet Suburban-original alternator 19244746 130 amp 111 Reviews LIMITED LIFETIME REPLACEMENT Part # 8237A