350Z Battery Drain

Hey, I'm having a weird issue with my 2004 Nissan 350Z with a gasoline engine. The battery keeps draining like crazy. I'm getting error messages on the speedometer, the lights are weak and flicker sometimes, and the error memory has a code stored. The engine cranks weakly when I try to start it, pointing to low battery voltage. I've checked the battery terminals and they seem clean and tight. I'm suspecting a defective battery sensor, maybe that's causing the electrical system to misbehave and not properly charge the battery. Has anyone run into something similar with their Z?

4 comment(s)

I had a similar experience with my old BMW 3 Series. The symptoms sound very familiar. A heavily discharged battery, error messages...it all points to an electrical issue. Did you check the battery's voltage with a multimeter? What voltage does it show when the engine is off and when it's running? If the charging voltage is low, it confirms the battery isn't getting enough charge.

Thanks for the quick reply! I haven't checked the voltage with a multimeter yet, but I can definitely do that. Where exactly did you find the problem with your BMW? Was it also a faulty sensor, or something else entirely? I'm trying to narrow down the possible causes before I start throwing parts at it.

In my case, it turned out to be a faulty voltage regulator within the alternator. It wasn't providing the correct charging voltage to the battery, which eventually led to it draining completely. Given your symptoms and suspicions of a defective battery sensor, it's best to get it properly diagnosed at a workshop. They can perform a thorough check of the entire electrical system to pinpoint the exact cause.

Thanks for the insight! I appreciate you sharing your experience with the BMW. I'll take your advice and bring it to a workshop to get it properly diagnosed. It was indeed a defective battery sensor. The repair set me back 315€, but at least the issue is resolved.

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