2007 Accord...4 cyl...167,000 miles and never had issues before.....Just changed air filter which was HEAVILY CAKED in grime. Very surprised it could breathe at all !!

Put PREMIUM GAS IN TANK (2/3 FULL) and a bottle of FUEL INJECTOR CLEANER.

After one day of sporadic/normal city driving, the check engine light came on with code: P0240 ....and was told it's a common code indicating a possible catalytic system malfunction plus other symptoms.

Do you think the NEW AIR FILTER, PREMIUM GAS, and FUEL INJECTOR CLEANER could have triggered a faulty code display or "tricked" the system into generating the P0240 code??

Thanks!!!....and yes, the air filter was literally caked in grime and dirt. Never seen one so badly clogged!!

Mike

 

p0240 or p0420 ??? p0420 would either be a bad cat or a bad primary oxygen sensor. first try re-setting the ECU and see if that works because a drastic change in airflow and temp could set off that code since the ecu automatically adjust air/fuel ratio. reset the ecu and perform the idle re-learn procedure.