I think the VTM code 77 may be related to the EGR valve. I see references to VTM-4, code 77, EGR, and a TSB with pilots. I’ve seen weak O2 sensors on some Nissans …
code p0420 honda ridgeline Direct Download speed 7287 Kb/s
code p0420 honda ridgeline Full Version speed 5567 Kb/s
A P0420 code is a trouble code on OBD-II equipped vehicles. All vehicles from 1996-newer sold in North America support this generic powertrain code.
P0420 documents back to top of this page Below are links to Honda/Acura documents of two kinds: Technical Service Bulletins, and Honda Service News (HSN) issues.
Installing removal of catalytic converter is bank 1 n 2 valve adjustment and passenger side CV axle removal.
Honda Trouble Codes. 85 Accord, 85-87 Civic. ECU Location. The ECU is located under the passenger’s seat. Codes are displayed on a series of four LEDs.