Subaru Sambar's Electrical Gremlins: Battery or More?

I had nearly identical issues with my 2004 Subaru Vivio last year. Being somewhat experienced with basic car maintenance, I first suspected a simple dead battery case, but it turned out more complex. The electrical system showed similar symptoms, flickering lights, unusual error messages, and that dreaded slow cranking. After unsuccessful attempts with a new battery, I took it to a workshop where they diagnosed a faulty battery sensor causing excessive battery drain. The repair cost was 315€ which included: Diagnostic testing of the electrical system, Replacement of the defective battery sensor, System recalibration, New battery terminal connections Since the fix, the vehicle battery has maintained proper charge and all electrical gremlins disappeared. The workshop explained that faulty sensors can cause the car to misread battery levels, leading to incorrect charging patterns. To better assist with your case, could you share: How old is your current battery? Does the battery warning light stay on? Have you noticed any correlation between the issues and weather conditions? Were there any recent electrical modifications to your vehicle? This information would help determine if your Sambar is facing the same underlying issue as my Vivio did.

Thanks for sharing that detailed experience. In my case, the car has about 101839 KM and the battery is just 8 months old. The discharged battery symptoms started appearing suddenly last week, with no warning light on the dashboard. The problem seems worse after the car sits overnight, suggesting a parasitic drain. I checked the battery terminals and they appear clean with no visible corrosion. The alternator belt also looks fine and properly tensioned. I will take your advice about having the battery sensor checked. The vehicle battery issues match exactly what you described, especially the unusual electrical glitches and slow starts. A proper diagnostic test sounds like the best next step before simply replacing parts. Would replacing just the battery sensor require any special programming for the Sambar electrical system?

Thanks for those additional details about your Sambar. When I got my sensor replaced on my Vivio, the workshop did need to perform some basic reprogramming. However, the Sambar system might be simpler than what I dealt with. The similar symptoms between our cases, particularly the discharged battery after sitting overnight, strongly suggests a parasitic drain situation. With your battery being only 8 months old, I really doubt the vehicle battery itself is the core issue. In my repair experience, the programming after sensor replacement involved: Basic electrical system reset, Battery monitoring system calibration, Testing the charging circuit Total shop time was about 2 hours Before going to the shop, try this basic test: Wait 20 minutes after shutting off the car, then check if the battery terminals feel warm. My faulty sensor caused noticeable warmth even when the car was off, indicating unwanted current draw. Given the age of your battery and the sudden onset of problems, I suspect your repair cost might be lower than what I paid, possibly around 220€ if its just the sensor. The electrical system in these models is generally reliable once the actual problem is properly diagnosed.

Thanks for all that information. The overnight battery drain definitely sounds similar to your situation. I measured the battery voltage this morning and it was at 11.2V after sitting all night, which seems to confirm the parasitic draw you mentioned. I called the workshop and scheduled a full diagnostic test for next week. They quoted 85€ for the complete electrical system check, which seems reasonable given the complexity of these battery charging issues. I did the warm terminal test you suggested, interestingly, the negative battery terminal does feel slightly warmer than the positive one. This seems to support your theory about the faulty sensor causing battery failure through constant drain. The estimated 220€ repair cost is actually less than I expected for fixing these electrical gremlins. Much better than repeatedly replacing perfectly good batteries or risking getting stranded with a discharged battery. One last question before I take it in, did the repair shop need your vehicle for a full day to complete the sensor replacement and programming, or was it a shorter job?