Outback Sport TPMS Sensor Malfunction Fix Guide

I had a similar TPMS issue on my 1998 Impreza, which shares many components with your Outback Sport. As someone with some experience working on Subarus, I can share my troubleshooting journey. The TPMS warning light kept coming on despite proper tire inflation. After checking the air valve and tire pressure multiple times, I took it to my regular workshop. They diagnosed it as a sensor fault caused by dead sensor batteries, which is common in these older models. The repair involved replacing the TPMS sensors, as the batteries are integrated and cant be replaced separately. Total cost was 280€ for parts and labor, including reprogramming the new sensors. Before suggesting specific solutions for your case, could you share: Have you noticed if the warning appears on specific tires? When was the last time your TPMS sensors were replaced? Does the warning come on immediately after starting the car or during driving? What exact error code is showing up in your diagnostic scan? This information would help determine if youre dealing with the same sensor battery issue or potentially a different TPMS system problem.

Last service was at 171000km and my current mileage is 172461km. The warning appears out of nowhere on all tires, which made me suspect a system issue rather than individual sensor failures. Getting conflicting pressure readings between my manual gauge and the car system was the first red flag. The diagnostic scan shows error code P0420 along with the tire pressure warnings. Based on the prices mentioned, 280€ for a complete sensor replacement seems reasonable compared to constantly dealing with these false alarms. My only concern is whether replacing all sensors will actually resolve the error code or if there could be an underlying electrical issue affecting both the TPMS system and other components. Would appreciate input on whether I should tackle the TPMS issue first or investigate the P0420 code separately. The dealership quoted significantly higher prices for both repairs.

After reading about your P0420 code alongside the TPMS issues, I think we might be looking at separate problems here. On my Impreza, I initially thought everything was tied to the tire pressure sensors, but it turned out to be more complex. The P0420 code typically indicates catalyst system efficiency below threshold, completely unrelated to the tire pressure monitoring system. When I faced this combination of issues, I tackled them separately: 1. TPMS: Replaced the sensors first since the unusual tire pressure warnings were affecting daily driving. The pressure gauge readings confirmed my suspicion that the sensors were failing. 2. P0420: This required separate diagnosis and ended up being a catalytic converter issue. In my case, fixing the TPMS didnt affect the P0420 code at all. The 280€ I mentioned earlier only covered the tire pressure sensor replacement. Based on your mileage and symptoms matching my experience, Id suggest: Start with the TPMS repair since its the less expensive fix, Have the catalyst system checked separately, Keep using your manual tire pressure gauge for accurate readings until the sensors are replaced, Consider getting a second opinion on repair quotes, especially for the catalytic converter work The dealer prices are usually much higher than independent shops for these specific repairs.

Thanks for the detailed feedback about handling these issues separately. After getting my TPMS sensors fixed last week for 280€, the unusual low tire warnings finally stopped. The pressure gauge readings now match what the car system shows, so that part is resolved. Still need to address that P0420 code though. Been getting quotes from different shops since the dealer price seemed excessive. Found a reputable independent shop that specializes in exhaust work and their estimate for the catalyst system repair is much more reasonable. For anyone else dealing with similar sensor fault issues in older models, dont assume all error codes are connected. Getting a proper diagnosis and fixing one system at a time helped avoid unnecessary repairs and costs. The tire pressure sensor replacement was definitely worth doing first since those false low tire warnings were driving me crazy during daily driving. Thanks again for the guidance. Time to schedule that catalytic converter check and finally clear all the warning lights.