94 BATTERY DRAINAGE PROBLEM - POSSIBLY ALTERNATOR??

[safleming72]

I JUST FINISHED REPLACING TRANSMISSION SOLENOIDS, THANK YOU TO EVERYONE WHO HELPED AND POSTED IN THE PAST WITH GREAT INFO, AND NOW I HAVE RUN INTO ANOTHER PROBLEM. FIRST OFF THE CAR HAS SET FOR ABOUT 15 MONTHS BECAUSE OF THOSE STUPID SOLENOIDS, IF I KNEW IT WAS AS EASY AS IT WAS I WOULD HAVE REPLACED THEM LONG AGO, SO I KNEW I MIGHT HAVE A FEW PROBLEMS. SO FAR THE ONLY THING I HAVE ENCOUNTERED IS THE BATTERY BEING DRAINED. HERES WHAT HAPPENS: I WORK AT NIGHT SO I DROVE TO WORK WITH LIGHTS, HEATER, AND RADIO ALL ON WITH NO PROBLEM UNTIL I CAME TO A LONG STOP LIGHT. THE SERVICE ENGINE LIGHT CAME ON, ABS LIGHT, TRACTION DISABLED, AND BATTERY LOW VOLTAGE ALL CAME ON, THEN THE INSTRUMENT PANEL FLICKERED AND THEN WENT DARK. AS I LEFT THE LIGHT THEY ALL WENT OFF , THEN BACK ON, THEN BACK OFF, THEY DID THIS OVER AND OVER UNTIL I TURNED THE HEADLIGHTS OFF, THEN EVERYTHING WAS FINE, UNTIL I TURNED THE LIGHTS BACK ON AND IT ALL STARTED AGAIN. WHEN I LIMPED IT HOME I TURNED THE CAR OFF AND THEN TRIED TO RESTART IT BUT IT WOULDNT START. I CHECKED THE CODES, I CANT REMEMBER WHAT THEY WERE EXACTLY, BUT WHEN I LOOKED THEM UP THE ONLY TWO WERE BATTERY LOW VOLT AND VOLTAGE OUT OF RANGE. I CHECKED AND CLEANED THE BATTERY POSTS THOROUGLY AND THINKING IT MIGHT JUST BE AN OLD BATTERY I BOUGHT A NEW ONE. EVERYTHING WAS FINE FOR TWO DAYS AND THEN ON THE WAY TO WORK THE SAME THING HAPPENED WITH THE LIGHTS BUT THIS TIME THE CAR DIED AFTER ONLY A FEW MINUTES OF RUNNING LIKE THIS. EVERYTIME THIS HAS HAPPENED I HAVE CHECKED THE CODES AND HAVE FOUND NOTHING ABOUT ALTERNATOR PROBLEMS OR BATTERY NOT CHARGING, ONLY BATTERY LOW VOLTAGE. I AM GOING TO HAVE THE ALTERNATOR CHECKED IN THE MORNING. DOES THIS SOUND LIKE A BAD ALTERNATOR OR POSSIBLY SOMETHING ELSE. I HAVE CHECKED THE BATTERY POSTS SEVERAL TIMES AND THE ARE TIGHT AND CLEAN. ANY INFO IS GREATLY APPRECIATED. THANKS EVERYONE. OH ALSO IT SAYS IN THE MANUAL THAT I CAN MONITOR VOLTAGE BY TOGGLING THE INFORMATION BUTTON, I HAVE TRIED SEVERAL TIMES BUT THE ONLY THINGS THAT COME UP ARE MPG, FUEL USED, AVG MPH, AND TIMER. ANY IDEAS??? THANKS AGAIN.

[PAUL T]

If I remember right the voltage data is under the "PCM DATA" information. I do not have my manual handy to tell you what "PDXX" it is. You may need to check your body grounds. Follow the battery ground wire to the frame connection and check it for starters. You also need to check your PCM connection for corrosion and tightness. Have the new battery load tested, even though it is new it could be bad. Trunk lights, visor lights, and glovebox lights are drainers, you could make sure they go out.

[Cadillac Jim]

When the battery voltage gets below 9 Volts, the sensors and modules don't work right and you can ignore any codes not related to low battery voltage.

Low battery voltage can be caused by a lot of things, most commonly a problem with the battery. Just letting a car sit for long periods of time will lat the battery go dead after a few weeks and the longer it stays that way, the less strength you will see when it is recharged. The first thing I would check is the battery not retaining a full charge.

The battery ground cable(s), on both ends, are important to check, as is the engine ground strap. I see from your profile that you have a 1994 Northstar, 270 hp. Thus it is probably an SLS, right?