Failing Subaru Pleo Alternator Symptoms & Solutions

As someone with some hands-on experience with car electronics, I dealt with very similar charging system issues on my 2006 Subaru R2. The symptoms match exactly what I experienced, multiple warning lights, dim headlights, and starting problems all pointed to voltage drop issues. After basic testing showed the battery was good, the workshop performed a thorough charging system diagnosis. The alternator was indeed failing, causing inconsistent power delivery throughout the electrical system. The serpentine belt was also showing wear, so they recommended replacing both components. The complete repair involved: Alternator replacement, New serpentine belt installation, Full system diagnostic, Battery terminal cleaning Total cost was 960€ which included parts and labor. Since the repair, all electrical issues were resolved and the car has been running perfectly. Before you proceed with repairs, could you share: current battery voltage readings (if measured), whether the battery warning light stays on while driving, if you notice more issues during nighttime driving, The approximate mileage of your vehicle This information would help determine if your symptoms truly match the alternator failure pattern I experienced.

Last service was done at 146720 KM where they did a thorough inspection of the charging system. The voltage readings I took with a multimeter showed only 12.1V when running, dropping below 11V under load. The battery light does stay illuminated while driving and all electrical issues definitely worsen at night with headlights on. Unlike your case, my serpentine belt was recently replaced during that service, so at least that component should be good. Your detailed repair breakdown is really helpful, good to know the alternator issue presents such similar symptoms across different Subaru models. The alternator replacement cost estimate from my local shop is slightly higher at 1150€, but the current voltage readings make me think it is indeed necessary to fix the charging system to prevent any potential engine misfire or complete electrical failure.

Thanks for those voltage readings, they really confirm what I suspected. Those numbers are almost identical to what I saw on my Pleo before the alternator failed completely. When my alternator was healthy, it maintained 13.8-14.4V while running, so your 12.1V reading with drops under 11V definitely indicates a failing charging system. While your serpentine belt is new, the alternator symptoms perfectly match the classic voltage drop pattern. The test readings plus the battery warning light staying on are textbook signs of alternator failure, not just a simple battery issue. The 1150€ quote seems reasonable for a complete alternator replacement with diagnostic work. Just make sure they do a full charging system test after installation, when I had mine replaced, they found a corroded ground wire that also needed cleaning to restore proper voltage. The car electronics should recover completely once the new alternator is installed. My Pleo went from barely starting to running like new, and all those warning lights and electrical gremlins disappeared. Most importantly, fixing it prevented potential damage to other electrical components from continued low voltage operation.

Thanks for those detailed answers everyone. After monitoring my voltage readings more closely over the past few days, the situation is getting worse. The battery drops to 10.8V now during nighttime driving, and this morning I had my first engine misfire event. Given the clear voltage drop pattern and the deteriorating charging system performance, I will proceed with the alternator replacement next week. The 1150€ quote seems fair based on the experiences shared here, especially since it includes a full system diagnostic. While it is more than I hoped to spend, preventing further electrical damage makes it worth the investment. Will make sure they check all ground connections during the repair as suggested. Really appreciate all the insights about the charging system symptoms, they helped confirm this was indeed an alternator issue rather than just a low battery problem. Looking forward to having stable voltage readings again and no more flickering lights or warning indicators.