Subaru Throttle Sensor Issues Causing Power Loss

Having dealt with almost identical symptoms on my 2003 Subaru Legacy GT, I can share my experience. The check engine light came on and the car felt sluggish, especially during acceleration. After noticing reduced throttle response, I had the car checked. The workshop diagnosed issues with the electronic throttle control system. The throttle sensor was sending incorrect signals, causing the ECU to limit engine power as a safety measure. The air flow readings were inconsistent, which triggered the check engine light. The repair involved replacing the complete accelerator pedal module, as the internal electronics were faulty. Total cost was 265€ including diagnostic time and parts. Since the fix, throttle response returned to normal and the check engine light has stayed off. Could you share: Exact Subaru model and engine size, any other warning lights besides check engine, Does the throttle feel unresponsive at specific RPM ranges, Have you noticed any changes in idle behavior This would help confirm if your issue matches what I experienced. The throttle body system is pretty similar across these model years, but knowing these details would help provide more specific guidance.

Last service was at 59277 KM and the throttle response issues started shortly after. When my mechanic hooked up the diagnostic tool, it confirmed throttle sensor malfunctions, plus irregular engine idling patterns at cold start. The engine enters limp mode out of nowhere during acceleration, limiting power output significantly. This matches exactly what described about the ECU safety measures. The idle behavior definitely worsens when the engine is cold. My throttle body was also quite dirty when inspected, which likely contributed to the poor fuel efficiency. The mechanic quoted 310€ for a complete electronic throttle body replacement including labor, slightly higher thans repair cost. Good suggestion to check the accelerator pedal module, will have that inspected too during the repair.

Thanks for those additional details about your Subaru. The symptoms you describe with the engine idling issues and limp mode match my experience perfectly. The dirty throttle body you mentioned can definitely compound these problems. When my throttle sensor started failing, I also noticed the cold start issues getting progressively worse. The air intake system became less responsive over time, particularly in the first few minutes after starting. One thing I learned during my repair, the throttle body cleaning alone rarely fixes the underlying electronic issues. While the 310€ quote is a bit higher than what I paid, a complete throttle body replacement is often the most reliable fix when you have these combined symptoms. The response delay you mention during acceleration is a classic sign of the throttle sensor failing. Since your diagnostic results already confirm sensor malfunction, I would proceed with the replacement rather than just cleaning. In my case, trying to save money with interim solutions just meant paying for diagnostics twice. Make sure they also check the wiring harness connections during installation. A loose connection can cause similar symptoms and you want to rule that out while they have everything apart.

My previous concerns about the throttle sensor were definitely confirmed bys responses. The failing throttle body electronics are showing the exact same symptoms they experienced, especially the cold start issues and unusual limp mode activation. The air flow problems get worse each week, and my check engine light stays on constantly now. After comparing experiences, the 310€ quote for a complete throttle body replacement seems reasonable, considering both parts and labor. Rather than waste time with partial fixes, Im scheduling the full replacement next week. Will make sure they inspect the accelerator pedal module and wiring harness too, since those could contribute to the throttle response issues. Really helpful to hear from someone who went through the same repair. This gives me confidence that replacing the throttle body assembly should restore proper engine performance and resolve the air intake problems Im experiencing.