2001 Chevrolet Blazer

Question

I have a 2001 Chevy S-10 Blazer LT 4X4 with a 4.3 V-6 that will not start unless it is jump started... After the Blazer is jumped it will idle all day but when I try to drive it down a small hill in our driveway with the tranny in neutral & at around 2500 RPM's the Blazer will stall and can not be started again unless it is jumped... Bought and installed a new battery and still it will not start unless jumped... Before I replaced the battery I scanned the Blazer for trouble codes and P1638 was all that showed up... Would a bad alternator keep the Blazer from starting???
God bless and thanks a LOT!!!!

Answer 1

P1638 Generator F terminal circuit

How good the battery terminal. If need be replace the battery terminal.

The alternator should be checked, What you should have is good battery at 12.5 volts and the charging system should be 2 volts above battery voltage

 Here a alternator that set a P1638, what happen here is the alternator was benched tested, and reinstalled, but the vehicle at some distance would stall out, The best way to test P1638 was to measure the charging system at first igntion start up the charging system will be good, Turn the vehicle off and restart the engine. if the charing system is lower than  first up you have a faulty alternator.