Unexpected car troubles can be frustrating, especially when they manifest as a cascade of warning lights. For owners of a 2010 Subaru Legacy 3.6R, encountering a check engine light, VSC light, and flashing cruise control and brake lights can be alarming. Often, the first step in diagnosing these issues involves using an OBD2 scanner to read trouble codes. But what happens when the problem is more… organic? This was the experience of one Subaru owner who discovered a less conventional cause behind their dashboard light display: rodent damage.
The story began with a seemingly normal day and a dead rat found near the car. Shortly after, upon starting their 2011 Subaru Outback 3.6R (similar in many respects to the 2010 Subaru Legacy 3.6R), the dashboard lit up with warnings. An OBD scanner pointed to a knock sensor issue – specifically, knock sensor #2. For those unfamiliar with Subaru engine layouts or the OBD2 location in these models, the immediate next step might not be obvious.
Upon investigation, the owner, new to Subaru ownership, located the knock sensors and quickly uncovered the culprit. A rat had not only made a nest under the intake manifold but had also chewed through the wiring of the knock sensor. This explained the OBD2 scanner’s diagnostic code and the resulting dashboard light show.
Initially, a temporary fix was implemented by reconnecting the damaged wires with electrical tape. This makeshift repair allowed the error codes to be cleared, and the flashing lights ceased. However, as expected with engine heat, the tape soon failed, and the warning lights returned. A more permanent solution was clearly needed.
To address the issue properly, the owner consulted a shop manual and ordered necessary intake gaskets. The repair process involved removing the intake manifold, a task described as “a pain in the neck” due to the various hoses, fuel lines, and sensors involved. While the manual suggested extensive disassembly, the owner found ways to streamline the process.
With the intake manifold removed, the full extent of the rodent damage became apparent. Wiring for both knock sensor #1 and #2 had been affected, although thankfully, only #2 was completely severed. For knock sensor #2, wire strippers were used to expose more wire for a better connection. A butt connector and crimping tool were employed to create a more reliable and lasting repair than the initial tape job. Everything was then wrapped securely with electrical tape for added protection.
While the engine was disassembled, preventative maintenance was also performed, including cleaning ground wires and the throttle plate, which had accumulated significant grime over 147,000 miles.
Upon reassembly and starting the Subaru, the problem was resolved. The warning lights were gone, and an unexpected bonus was smoother throttle response, likely due to the throttle plate cleaning. This experience served as an intense introduction to Subaru’s horizontally opposed “pancake” engines and the challenges of their tight engine bay packaging.
For owners of a 2010 Subaru Legacy 3.6R or similar models experiencing unexplained check engine lights, especially after noticing signs of rodents, inspecting the knock sensor wiring is advisable. While the OBD2 location itself is typically easily accessible under the dashboard, understanding the codes and tracing the potential issues, as highlighted in this case, can lead to uncovering unexpected problems like rodent-damaged wiring. This DIY repair demonstrates that with some resourcefulness and effort, even seemingly complex issues can be resolved at home.
