My 2003 fuel tank was replaced for free from the dealer under a leaking filler tank recall. I had the dreaded P0440 code. A month later I replaced the Fuel Pump with a Bosch unit which is stock. The P0440 never went away and I threw money at various Evp parts to no avail. Chevy wanted to charge me $80 to diagnose the issue I said hell no after they replaced my fuel tank. I chalked it up to the brain unit just giving a false reading as I replaced many parts , 02 sensors back and rear, ign coils, etc . Just did a oil change and fuel filter change and hadn't run the OBD Fusion app in a while and got the P0133 code?
Possible causes
Possible causes
- Faulty Front Heated Oxygen Sensor Bank 1
- Front Heated Oxygen Sensor Bank 1 harness is open or shorted
- Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
- Inappropriate fuel pressure
- Faulty fuel injectors
- Intake air leaks may be faulty
- Exhaust gas leaks