My wife's 2002 VW TDI Jetta Wagon recently had the battery dashboard red battery light come on. My attempt to recharge the battery recognized that a battery failure was the cause. I had previous checked with my VW service people at my VW dealership to assure that any attempts to recharge wouldn't endanger the computer electronics.
<br/> I also recognized that replacing this battery would mean a reset of the same VW computer system, because as you already know when you remove the battery on the newer VWs it causes the computer to require a reset which if not done correctly can cause serious problems. Therefore I decided to have my VW dealership do the job. While driving to my VW dealership the following dashboard lights appeared - Airbag, ABS, and the Battery light. When the RPMs reached above 2500 the Airbag and ABS light would go off, but the Battery light wouldn't.
<br/> The VW dealership testing found that there was a dead cell in the battery. They also found that the alternator was only producing 50% of the power needed. Therefore we agreed to replace both the battery and alternator.
<br/> My question here is could the battery problem caused alternator problem???
<br/> This battery was the original batter placing it's age just over 5 years. What made this situation a real mindtwist was that I had identified that this battery should be replaced one day prior to the Battery light appearance.
<br/> My thought here is that if such a battery failure could cause a related alternator failure, then periodic battery testing when the battery gets older should be a recognizable desired preventive maintenance issue - right?