The 2AZ-FE engine has it’s fair share of common Check Engine Light (CEL) codes. You can take your car to the local O’reilly or Autozone and they will pull the code for FREE, or you can equip yourself with a basic OBDII code reader to attempt a DIY diagnostic and fix.
Here are the most common CEL codes for the 2AZ-FE engine
P0171 — System Too Lean (Bank 1)
- Vacuum leaks, cracked hoses
- Dirty or failing MAF sensor
- Intake gasket leaks
- PCV issues
P0351, P0352, P0353, P0354 Cylinder-Specific Misfires
- Bad ignition coil on that cylinder, P0351 cyl 1, P0352 cyl 2, etc
- Fouled or worn spark plug
- Broken or faulty ignition coil harness
- Injector or fuel delivery issues
P0420 — Catalyst Efficiency Below Threshold
- Bad Catalytic Converter, very common on aging 2AZ-FE
- Bad upstream air/fuel or downstream O2 sensor
- Oil consumption contaminating the cat
P0100 / P0102 / P0103 — MAF Sensor Circuit Codes
- Dirty MAF
- Wiring issues
- Intake air leaks after the MAF
P0110 / P0115 — Intake Air Temp or Coolant Temp Sensor
- Faulty temperature sensor
- Wiring or connector problems
- Can cause hard starts and poor fuel economy
P0440 — EVAP System Malfunction
- Loose or bad gas cap
- Cracked EVAP hoses
- Canister issues
P0441 — EVAP Incorrect Purge Flow
- Failed purge valve
- Blocked EVAP lines
- Very common with age
P0130 / P0133 — O2 Sensor Circuit / Slow Response
- Aging upstream oxygen sensor
- Exhaust leaks near sensor
- Oil consumption contamination
P0505 — Idle Control System Malfunction
- Dirty throttle body
- ECU idle relearn not completed
- Vacuum leaks
P0010 / P0011 — VVT System (Intake Cam Timing)
- Dirty or sticking VVT oil control valve
- Sludged oil passages
- Low or dirty oil
