Exhaust System Leak or Heat Shield Rattle
A continuous noise from under the car on a 2020 Subaru Outback is often due to an exhaust leak or a loose heat shield. The sound may be a rattle, hiss, or metallic vibration that persists regardless of driving conditions.
Diagnosis Details
Possible Causes
Loose or corroded exhaust heat shield vibrating against the exhaust pipe or underbody.
Exhaust system leak at a gasket, flange, or cracked pipe, causing a hissing or ticking sound.
Damaged or worn exhaust hanger allowing the exhaust system to contact the chassis.
Related OBD-II Codes
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What You Should Do
Inspect the underside of the vehicle for loose heat shields, especially around the catalytic converter and muffler.
Check for exhaust leaks by listening for hissing or feeling for escaping air with the engine running.
Tighten or replace any loose shields, and repair exhaust leaks as needed.
Related Repairs
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Disclaimer: This AI-generated diagnosis is for informational reference only. Always consult a qualified mechanic for an in-person inspection. AutOwner is not responsible for decisions made based on this information.