[Richard Kirshy]

https://www.engine-codes.com/p0420_nissan.html

[Richard Kirshy]

If your having a combination of codes, best to determine if they are some how connected to each other or separate.
Most ( if not all) codes can be looked up on the internet.
Even many by specific MFG’s.
In many cases a code will point you in a direction say a fault with a O2 heater circuit .
In that case the O2 heater may be faulty also the wiring, connector, ECM connection or the ECM itself maybe at fault.
A complete diagnostic will point out the issue to prevent firing the parts cannon and wasting $$$.

[Richard Kirshy]

Anything is possible but…..
Personally. I have never seen or heard of a rock or something loosening a caliper bolt in almost 50 years of working on cars.
I have heard of rocks jammed to the head of a caliper bolt but never loosening one.

I think the dealership is trying to cover their butt.

Just for giggles, do a search on google, yahoo and any other search engines and look up rock loosening caliper bolt.
Print out the results and show the person who told you that foolishness.

[Richard Kirshy]

Some codes can be quite specific as to their issue.
Many others not so much..
IE. P0456, a small EVAP leak.
There are several possible areas on the vehicle that can cause this DTC.
Only way to determine the exact point of failure is to trouble shoot the entire system.

[Richard Kirshy]

Many go for aftermarket replacements for the exact reason you stated.. cost.
But like everything else in life.. you get what you pay for.
I wouldn’t go for the cheapest for the reason if they do fail prematurely you’ll have to do the job twice.
JMHO.

[Richard Kirshy]

Much tougher to clog any muffler than a cat.
Sounds like you may have a partially clogged cat.
Depending on how your ECM is programmed todetermines an actual fault

[Richard Kirshy]

If your going through all the time and effort to do a complete rebuild.
My suggestion would be to get OEM parts from Toyota.

[Richard Kirshy]

Once you get eyes on the mounting hardware and depending on its condition.
At best you’ll just need sockets and a ratchet for removal
At worst, lot of penetrating oil, a torch, air hammer and chisel, grinder and cut off wheels etc.

[Richard Kirshy]

You do not offer much information …
A compression and leak down test would give you a pretty good insight on the internal mechanical health of the engine.

[Richard Kirshy]

See if these are correct:
https://shop.advanceautoparts.com/find/chevrolet-colorado-oil-pressure-switch-connector

[Richard Kirshy]

Check for any codes.
It would be useful to hook up to a scan tool and look at live data.

[Richard Kirshy]

You have a tank venting issue.

[Richard Kirshy]

Could be a number of possibilities:
But being the noise happened when you turn the wheel, I would start with the list I posted.

[Richard Kirshy]

Check your ball joints, sway-bar, steering and CV axles

[Richard Kirshy]

I would use never-seize on the shaft area that passes through the bushings and perhaps some spray cosmoline rust preventative on the nuts and threads

[Author]

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