Some 2008-12 Accord and Odyssey, 2009-12 Pilot and 2010-12 Crosstour models (all with V6 engines) may intermittently turn on the check engine light and log trouble code P3400 and/or P3497 in the PCM. One likely cause for the trouble, reports Honda, is a sticking rocker arm oil pressure switch. The problem can occur on one or both banks of the engine.
Installing a new-design pressure switch and O-ring (part # 37240-R70-A04 and part #91319-PAA-A01), respectively) should eliminate the trouble.
Before ordering the new parts, however, check the engine oil dipstick because a low oil level can also cause these codes to set. If the oil level is low, add oil, clear the code(s) and release the vehicle to the customer. If the oil level is okay or the vehicle comes back with the same complaint, replace the front and/or rear pressure switch and O-ring, depending on the code(s) logged. For reference, the location of each rocker arm oil pressure switch is shown in the illustration.