P0420 Toyota -

Question

I just had work done on my 2003 matrix xrs and the mechanic forgot to tighten the oil cap where you fill oil into the car, and it fell out of the engine. The check engine light came on and the code on that is p0240. Would that cause this code? I have since replaced the missinh cap and car is running fine.

Answer 1

P0420 for Toyota means Catalyst System Efficiency Below Threshold Bank 1. It means the catalytic converter is not working corrrectly do to

Possible causes:

- Three way catalyst converter Bank 1
- Exhaust tube
- Intake air leaks
- Fuel injectors may be faulty
- Fuel injector leaks
- Spark plugs may be faulty
- Improper ignition timing
- Engine Control Module (ECM) 

you can reset the code and see if it comes back. Its possible it may be related to the oil cap issues