2002 Volkswagen Jetta Battery Drain

2002 VOLKSWAGEN
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DICKBONDY
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  • 1 POST
I bought a 2002 Jetta for my daughter and it was working fine last summer whan she was driving it every day. I have been trying to drive it once a week but left it unattended for approx 6 weeks before Easter. She had no problem starting it over Easter weekend, but on Sunday, the battery was dead. My mechanic could not find a drain on the battery, the battery was 18 months old so he trickle charged it and it was OK. I then left it for a week and the battery was dead again. I trickle charged it for 10 hours and it was OK. Today my mechanic found a 41 Milliamp drain, which he says is normal. He replaced the battery under warranty. Could there be anything else going on here? Like a short that's draining the battery?
May 1, 2006 at 3:41 AM
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LOSONE
  • ✓Experienced Mechanic
  • 1,616 POSTS
The paracitic load on the Jetta shouldn't be over 15 ma. 42 is too much as it is almost 1/2 amp. The best way to check the draw is to start with the alternator by disconnecting wires one at a time and see if it drops.

The amp meter should be in series with the negative battery lead on the amp scale.. If you don't have a digital voltmeter you canb get a good one for a bout $15.00

The VW alternators are famous for having a small drain problem. If it is good pull one fuse at a time and see when th current drops, When you isolate the circuit let me know. Good luck
May 1, 2006 at 7:24 AM
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Suggested Repair

Measure parasitic draw with an ammeter in series on the negative battery cable. A draw above about 15 mA is excessive. Disconnect the alternator wires one at a time to see if the draw drops, since VW alternators often cause a small drain. If it does not, pull fuses one at a time to isolate the circuit.

Conversation Summary

The owner of a 2002 Volkswagen Jetta reports repeated dead batteries after the car sits, even after a mechanic measured about 41 mA of draw, called it normal, and replaced the battery. The expert says the draw should stay under about 15 mA and recommends checking the alternator first, then pulling fuses one at a time to find the circuit causing the drain.

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