2016 Honda Accord LX
86,156 mi CVT
OBDII Codes:
P0172
P0420
P0087
83-11
61-11
OBD trouble codes aren't shopping lists. Your problem needs to be diagnosed by a mechanic first.
It could cost $10, or it could cost $1,000. You could have one problem, or you could have several.
Start by looking up your codes on obd-codes.com.
For starters, I'd say your fuel pump is going out.
It's not clear if you want Scotty to work on it or you want to know how much it would cost at a shop.
Either way it is not possible for us to tell from here. First of all, assuming the latter, we have no idea what the going rate is for mechanics in your area. Second of all it is unknown exactly how much work that thing really needs. As you may (or may not) know, codes do not tell you what part to replace. It's not as simple as that. To determine the actual cause or causes requires additional diagnosis and it's impossible to tell ahead of time of how long that will take or what the diagnosis will reveal.
Your best bet would be to obtain an estimate from a good local mechanic. Stay away from dealers and chain shops.
P0420
This code could be generated from something related to the exhaust system and not directly related to the catalytic converter.
There are two 02 sensors in the exhaust system. One before the catalytic converter and one after. If one is "lazy", especially the downstream one, it may trip that code.
Catalytic converters are designed to last the lifetime of the vehicle, and it is usually the last thing to suspect, especially considering the cost of a new one.
P0172
This could indicate a clogged air filter. Take the air filter housing apart and check it.
P0087
That might mean your fuel pump is going out.
83-11
61-11
These codes may be as simple as needing a new battery. From what both codes indicate, you currently don't have anti-lock brakes, which is hazardous.
There's no other way to tell from here.
@justin-shepherd how does a vacuum leak cause P0420? "The PCM sets P0420 if the average of calculated oscillation size of rear HO2S signal during predetermined duration is higher than the predetermined threshold." Maybe you mean exhaust leak.
Yeah, that's what I meant. I'll edit it.
Are you sure there's only a possible exhaust leak/ lazy 02 sensor? The way I understood it, the MAF determines the weight of air in grams per second, and the car's exhaust via the two oxygen sensors determine the combustion products. If unmetered air gets through the engine, wouldn't that possibly lead to errant results from the 02 sensors and trip that code, or is the intake side and exhaust side of the system fully independent from each other?
@justin-shepherd nope. A vacuum leak would cause a lean condition. Not wider O2 oscillation swings.
@justin-shepherd the theory of operation is described in service manuals:
https://charm.li/Honda/2011/Accord%20L4-2.4L/Repair%20and%20Diagnosis/A%20L%20L%20%20Diagnostic%20Trouble%20Codes%20%28%20DTC%20%29/Testing%20and%20Inspection/P%20Code%20Charts/P0420/Advanced%20Diagnostics/
@imperator That makes sense. I must have gotten the two conditions mixed up somewhere along the line. Thanks.