Subaru Exiga No-Start: Engine Fault Alert Mystery

Running a 2012 Subaru Legacy GT here and faced very similar starting issues. The root cause was corroded battery terminals causing intermittent connections, triggering multiple ECU failures and engine fault warnings. The engine diagnostics initially showed unusual error codes because the ECU was getting irregular power supply. This kind of issue can mimic serious engine surge problems and create misleading diagnostic results. The fix required: Complete cleaning of battery terminals, Replacement of corroded cable connectors, ECU reset after proper power restoration, Full system diagnostic scan to confirm resolution Despite appearing minor, poor battery connections can cascade into what seems like major engine issues. The irregular power supply can damage the ECU if left untreated. The fuel injection system is particularly sensitive to voltage fluctuations. Before taking it back to a shop, check your battery connections for: White/green corrosion buildup, Loose terminal fit, Frayed cable ends, Battery age (if original, might need replacement) This is often overlooked during routine maintenance but can cause significant problems. Get the terminals cleaned and properly secured before pursuing more complex diagnostics.

Thanks for sharing your experience. My Exiga had similar symptoms last month, the check engine light came on and it refused to start properly. The ECU failure symptoms matched exactly what you described. I also suspected complex issues at first, but after the mechanic checked, it turned out to be mainly electrical problems related to the battery connections. Id like to know how much you ended up paying for the full repair? Also, has everything been running smoothly since the fix, or have you noticed any other electrical issues? My engine software is still sometimes showing small glitches on cold starts, so Im curious if this is something you experienced as well.

After visiting my mechanic last month for the battery connection issues, they fixed everything for 155€. The work involved thorough cleaning, replacing corroded connectors, and running a complete engine diagnostics scan to ensure no residual problems. Since the repair, my engine control malfunction warnings have completely disappeared. The ECU is now getting consistent power, and the fuel injection system works perfectly. No more glitches or error codes on startup, even during cold weather. Regarding your cold start issues, this could indicate remaining loose connections or corrosion that wasnt fully addressed. The engine fault warnings during cold starts often point to voltage drops that become more apparent in lower temperatures. Would recommend having the connections checked again, particularly focusing on the ground wire connections. The investment in proper electrical repair saved me from much costlier engine diagnostics and prevented potential long-term damage to the ECU. My Legacy GT now starts reliably every time, regardless of temperature conditions.

After reading everyones helpful replies, I wanted to share how my situation got resolved. Took the car to a different mechanic who specializes in electrical systems. The total repair came to 180€, which included cleaning all battery connections, replacing two corroded terminals, and running a complete engine diagnostics check. The engine light issues were exactly as described, irregular power supply to the ECU causing false readings. The fuel injection system was getting confused by the voltage fluctuations, explaining the cold start problems. The mechanic also found some corrosion on the ground wire connection that the previous shop missed. Since fixing these electrical issues, my Exiga starts perfectly every time. The engine software readings are now stable, and I havent seen any warning lights for the past few weeks. Really glad I checked here first, saved me from unnecessary expensive repairs and helped point to the actual problem. Amazing how something as simple as corroded battery connections can cause such confusing engine fault warnings.