Hello Good People
My Mazda's been doing a pretty good job since July and I'm thinking of selling her.
The check engine light came on about 24 hours ago and the guys at AutoZone gave me 3 codes.

P1526 - same one I had this summer[:@],ABV Solenoid Valve(July19 post)
P0170 - could be 02 sensor, missfire or vacuum leak or injector
P0421 - catalytic converter failure, missfire or vacuum leak

Autozone guy says he thinks the p0170 &p0421 are related to the factory-code p1526... is he right?

Is the best bet that it's time to replace the ABV valve again?
Or should I look into the catalytic converter thing?

I need to sell the Mazda and get an SUV or truck, since we're expecting a baby in April, so I want to know whether to fix it and sell it, or knock the "fix it" price off of how much I would sell it for.

Your help is appreciated!

 

generally, you start with the lower number, and work your way up. the 0170 is a vacuum leak, very common. most likely one of the plastic vacuum tees. 0421 is the right bank cat, below threshold. while this MIGHT be the post cat o2 sensor, i think your cat is going, and you will need to replace it. i would just erase the code, and see if it returns in a short period of time. if it comes back in a couple of weeks, you need a cat. kinda expensive, and takes about 3 hours to change. the 1526 is the abv solenoid CIRCUIT, which could be related to the 0170. if you have a vacuum leak in that circuit, it will throw the 1526 code, and the 0170 code. if you fix the leak, both codes might go away. the 0421 code is not related, and it will come back. it might stay off for several months, but it will come back. there is an illegal way to erase it, but i dont feel good about this method.

 

Thanks Keninn!!

Quick Followup:
Any price ranges that are pretty standard with replacing the cat? (and I assume that's the catalytic converter, yes?) Can my husband do it or should we take it to a mechanic or a Mazda dealership? Or should we just sell it with the estimated "you might need to replace the catalytic converter, so we'll knock X amount of dollars off the price" disclaimer attached?

I'll see if we can start with the lower-numbered problems first (my husband replaced thesolenoid valvelast time and the light went off in the same day. i think the cost was around $60 for the part) and we can go from there.

Is there a certain way to check the plastic vacuum tees?

And how do we go about "erasing the code" - do i just ask the folks at Autozone?