2001 Subaru Outback 4-Cylinder P0328 Knock Sensor #1 Signal High - Diagnosis and Fixes
Hi everyone, I'm having an issue with my 2001 Subaru Outback 4-cylinder. The check engine light is flashing intermittently, and my OBD2 scanner shows a persistent P0328 code: 'Knock Sensor #1 Signal High'. I'd like to understand what causes this code, whether there's any troubleshooting or cleaning steps I can try before replacing the knock sensor, and how to properly test it. Any advice on common failure points or diagnostic procedures would be greatly appreciated. Thanks in advance! Poll
Knock sensors are often located deep within the intake manifold and can be difficult to access. Testing them directly is challenging. One method involves checking the sensor circuit for continuity. On some vehicles, you can temporarily tap the exhaust manifold with a hammer while monitoring the scanner—any change in engine timing would indicate the sensor is functional. However, due to their location, these tests are not always reliable and may require professional tools or equipment.