Car question

[Clodfobble]

Yeah, assuming that it really truly is a failing emissions level triggering the light, and not a poor gas mixture like Lamplighter suggested. If it's a gas mixture problem, turning off the light may allow it to stay off, or it may come back on again and then I'll know for sure.

[ZenGum]

Originally Posted by Clodfobble

Fuck. Check engine light is on. Got the codes read at AutoZone, they say:

P0421 - Warm up catalyst system (RH) efficiency below threshold
P0431 - Warm up catalyst system (LH) efficiency below threshold
P0174 - Lean Air/Fuel ratio bank 2

I know it will not pass inspection with this issue. But I just passed in November, so I'm safe there for 11 more months. My question is, is this a dangerous thing to be driving around with, or can it hang out for a few months with no real problems other than continuing to degrade a catalytic converter that is probably going to need replacement either way? I have to drive this thing for about 10 hours of holiday travel in just a couple weeks, and fixing it right now is going to be very painful.

Originally Posted by Clodfobble

Yeah, assuming that it really truly is a failing emissions level triggering the light, and not a poor gas mixture like Lamplighter suggested. If it's a gas mixture problem, turning off the light may allow it to stay off, or it may come back on again and then I'll know for sure.

Just pulling stuff out of my ear here but ...
The fact that both LH and RH (left hand and right hand?) catalysts are showing errors at the same time suggests either:
a. These catalysts are shitty and have a poor lifespan built in or
b. The catalysts are fine and the problem is caused by some factor shared between them, most likely the gas you are using.

B. Let it be b.

ETA: or c. the catalysts were fine but have been irreversibly cocked up by using shitty gas. Hope not.

[xoxoxoBruce]

You've got the cats, and some sensors (usually oxygen sensors) to report back to the computers how the cats are performing. A bad report could be a failure of either.

Only after you're sure of what the problem actually is, then explore your options
Here's a couple out of a list of 76.

[tw]

Originally Posted by Clodfobble

Yeah, assuming that it really truly is a failing emissions level triggering the light, and not a poor gas mixture like Lamplighter suggested.

The combination of codes imply a least expensive suspect. To say more requires information you cannot obtain.

Appreciate what you have and what is relevant. Oxygen sensors do nothing until the engine heats them to maybe 600 degrees. During a warm up period, the engine dumps larger amounts of gasoline into the engine. Much unburned gas is then burned by the catalytic converter when it gets hot.

Once the oxygen sensors get warm, then the engine computer changes a fuel input. Leans out the mixture based, in part, on data from an oxygen sensor.

Apparently you have two sensors. If one is proving bad data, then the engine will dump improper amounts of fuel into the engine. This can result either in a too lean mixture (causing exhaust valve failure) or too rich (causing catalytic converter failure).

A most likely suspect is a bad oxygen sensor. Fix it now to avert damage that may cost $thousands.

Bad gasoline causing this problem would be noted by mileage changes approaching maybe ten percent. Of the maybe 100 other possible errors associate with the converter, gasoline might only explain less than ten.

This failure could be something as simple as an oxygen sensor with a failed heater. Then the engine computer, after a delay, would be expecting data that was incorrect. Or it could be a thermal junction failure inside that sensor. Either way, a $100+ sensor is a least expensive solution. I believe you have two. Don't know if the shop will want to replace both or just one.

Again, your reply is only as useful as facts first provided. You (typically) cannot obtain numbers necessary for a better answer. The shop can.