P0432 Catalyst 2 - 1 Efficiency code

I've got a 01 XJ that has been throwing this code for past 220,000 miles or so. Engine now has 320,000. The check engine light burned out a few years ago because of it. Emissions are low enough that it can pass if the tailpipe emissions rather than codes are checked. In the past I've been told the mini-cats need to be replaced. Any chance this is only the O2 sensors?

Why did you ignore a CEL for 220,000 miles ? The cat converter and the O2 sensors have a service life of about 150,000 miles. Replacing the cat converter and O2 sensors is normal routine maintenance.


P0432 Jeep - Catalytic 2/1 Efficiency

Possible causes

- Warm Up Three Way Catalytic converter deterioration or malfunction
- Exhaust system leaks
- Loose front or rear HO2Ss
- Faulty front heater O2 sensor
- O2 sensors harness is open or shorted
- O2 sensors poor electrical connection


Tech notes

As the code description implies the P0432 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0432 code is combined with other codes, try fixing the other codes first.


When is the code detected?

The P0432 code is set when the Engine Control Module (ECM) detects rear HO2S value difference becomes closer to value of front HO2S. The ECM monitors when vehicle speed is 25-60 MPH, load is 22-45 percent and engine speed is 1000-3000 RPM.

Unfortunately you do need to get the mini cats replaced. Good thing you're not in NY, your car would fail inspection simply for the check engine light not working.

I've been monitoring it. No drivability issues and emissions are low enough. Why pay hundreds and hundreds of dollars to make a light go out? If it was simply an 02 for $55 I'd change it.

It would be reasonable to assume that the gas mpg's are less than they could be with correctly functioning emissions controls, thus replacing the cats and O2's would pay for itself in better mpg's.

I haven't noticed a fuel economy drop. It's gotten about 15-22 MPG since I've owned it. 15 with heavy city driving in the winter, 19 average city/highway in the summer, and about 20-22 summer interstate. Being held to 15-20 under the speed limit by camper trailers will boost fuel economy to 24 or more. I believe fuel economy is reduced overall by the high content of ethanol in fuel today. Crappy for everyone except the Midwestern farmers who get more for a bushel of corn.

It is most likely your mini-cats. A common misconception is that a cat efficiency code means replace the O2 sensor, when the O2 sensor is really telling you the cat needs to be replaced.

Jeep O2 sensors start getting lazy around 150k miles, but they still work well enough not to set a code. I had that same code on my 2000 at around 120k miles and I replaced the mini-cats. The light has been off since.

Here in emissions areas of Colorado, the CEL must work, but they cannot fail the car for the light being on.

My Wife's '07 compass has had a P0420 cat efficiency code on for nearly 70k miles.At 185k, It just went through it's first required emissions test this year and it 'fast passed'. Which is to say, it did not need to complete the test as it was running so clean.

To the OP: Fix the dead CEL, and as long as it passes the tail pipe test, save your coins for when it doesn't.

Thanks. How hard is it to change the bulb? Can I reach up there or do I need to pull the IC.

The cluster will have to come out.