AIR26 - Inspect Check Valve Function

NOTE: Check valve may "burble" as air is drawn in.

^ Key ON engine RUNNING.

^ Listen for escaping exhaust gas or feel for gas (only if engine temperature is at an acceptable level).

^ Is any exhaust gas escaping?

YES -- Replace check valve. Verify drive concern.

NO -- Return to diagnosis by symptom to address other possible causes. Diagnosis By Symptom