Has anyone gotten code P0420 and then had it cleared up by getting their ECM/PCM updated as per the TSB related to this issue? Before I start spending money on this problem, I wanted to know if anyone was successful in getting rid of the problem via the update.

Thanks!

Service Bulletin A04-063

Applies To: 2003 Accord L4 except SULEV – ALL
2003 Accord L4: MIL Comes On With DTC P0420

SYMPTOM
The MIL is on and DTC P0420 (catalyst system
efficiency below threshold) is set.

PROBABLE CAUSE
The ECM/PCM may incorrectly interpret sensor inputs
and set DTC P0420.

CORRECTIVE ACTION
Update the ECM/PCM software using the Honda
Interface Module (HIM).

 

The service bulletin is only applicable to the 4 cylinder.

 

Damn! Thought I was on to something. Thanks for the heads up.