Subaru R1 Electrical Issues Point to Bad Battery Sensor

Had nearly identical issues with my Subaru R2 from 2006, sounds exactly like what you are describing. As someone with some automotive repair experience, I recognized those classic voltage sensor problems right away. After basic battery testing showed the new battery was fine, vehicle diagnostics revealed the battery sensor was misreading voltage levels. This caused the car to think the battery was low when it actually had plenty of charge. The unstable readings were making the charging system behave erratically. Got it fixed at a workshop, they replaced the voltage sensor and recalibrated the charging system. Total cost was 315€ including parts and labor. Since then, no more flickering lights or hard starts. The stable voltage readings made a huge difference in how the electrical system performs. To help diagnose your specific case, could you share: Build year of your R1, When the battery was last replaced, whether you have done any battery maintenance, if you notice the issues more during cold starts, if any warning lights appear on the dash These details would help confirm if you are dealing with the same battery sensor issue I encountered.

Thanks for highlighting those matching symptoms. Recently completed service at 5405KM and can definitely relate to the voltage sensor problems you described. Had the dealer test the battery voltage and charging system since the battery was just replaced last month. Their diagnostics also pointed to an erratic battery sensor causing incorrect voltage readings, leading to those hard starts and electrical issues. The service found corrosion around the sensor connections which was disrupting proper battery maintenance signals. Will get the sensor replaced based on your experience since the symptoms match exactly. Good to know the fix worked well for your R2. My 2007 R1 shows the same flickering on cold starts, so sounds like we are dealing with identical low voltage symptoms. Just need to source the correct sensor part for my specific model year.

Thanks for the update on your R1's diagnosis. Glad to hear the dealer confirmed the battery sensor issues. Those corroded connections you mentioned are a common failure point that often gets overlooked during routine battery maintenance. After getting my sensor replaced on the R2, I made sure to add dielectric grease to the new connections to prevent future corrosion. This simple step helps maintain accurate battery charge readings and protects the sensor. For sourcing the part, the battery sensor for the 2007 R1 is nearly identical to my 2006 R2. Just ensure you get one with the right connector type since there were some mid-year changes. The part typically runs around 85€. Another tip from my experience, have them check the ground connections while doing the sensor swap. Poor grounds can cause similar low voltage symptoms and it is worth addressing while they are already working in that area. The battery testing after my repair showed much more stable readings. No more false low charge warnings or electrical gremlins. Keep us posted on how the fix goes for your R1.

I appreciate everyone's detailed input on this. Just had the work done today and wanted to share the outcome of my R1's battery sensor replacement. The repair went smoothly, total cost was 95€ for the sensor plus labor. They found additional corrosion on the ground connections just as suggested and cleaned those thoroughly during the service. The technician also applied dielectric grease to protect the new battery sensor from future corrosion issues. The difference in battery voltage stability is remarkable. After proper battery maintenance and sensor replacement, all electrical systems are working perfectly. No more flickering lights or hard starts, even during cold mornings. The battery charge now reads consistently and the charging system operates as designed. For anyone else facing similar symptoms, definitely get your battery sensor checked, especially if you have unstable voltage readings with a new battery. The diagnostic fee was worth it to pinpoint the exact issue rather than just throwing parts at the problem.