P0422 - Is it a fake code Topic is solved

Post by **xHeart** » 06 Dec 2018, 12:21

There aren't many references, not discussed often:
https://www.matthewsvolvosite.com/volvo ... ewer-codes

Post by **RickHaleParker** » 06 Dec 2018, 16:57

P0422 = Three-way catalytic converter (TWC) efficiency.

On a 1997 850 with M 4.4, P0422 = EFI-443.

Diagnostic trouble code (DTC) information EFI-443
EFI-443 Three-way catalytic converter (TWC) efficiency

A2301062 Condition
The engine control module (ECM) continuously monitors three-way catalytic converter (TWC) efficiency by comparing the signal from the rear heated oxygen sensor (HO2S) with the signal from the front heated oxygen sensor (HO2S). When three-way catalytic converter (TWC) efficiency deviates too much the engine control module (ECM) stores diagnostic trouble code (DTC) EFI-443.

Substitute value
none.

Possible source

uneven compression
air leakage in the intake system
air leakage in the exhaust system
faulty fuel pressure
defective three-way catalytic converter (TWC).

Fault symptoms
may result in poor performance.

Post by **xHeart** » 07 Dec 2018, 11:08

Thank you for the details.
The CEL is on our 2001 V70XC - ME7.

After reading your notes, my VIDA Search for P0422 returned it with corresponding ECM 4801: Permanent Fault.

The instructions for diagnose and check appeared confusing. Example: air leakage in the intake system - It says to remove Fresh Air Intake pipe from MAF and then connect tool xyz (Mityvac) to Fresh Air Intake pipe.

The item #9 is from MAF to turbo?

FWIW - disconnected vac tube from purge valve to intake port . Tested purge valve for vacuum leak. It passed, i.e. closed, holds vacuum.

The vac tube (the tube on right connects to port on purge valve & bottom tube goes to intake):

Post by **xHeart** » 07 Aug 2019, 14:18

The code P0422 returns intermittently.
The CEL goes away when ambient is above 90ºF, like today. What sensor to dust-off, clean?

Last month, it passed emission with a gentle reminder from the inspector to have it looked for code P0422.

Post by **abscate** » 08 Aug 2019, 03:10

Next year it might do the same. That same vacuum line system self destructed on my car a couple years back. You could try a smoke test for induction leaks

Post by **xHeart** » 15 Sep 2019, 18:29

abscate wrote: 08 Aug 2019, 03:10 Next year it might do the same. That same vacuum line system self destructed on my car a couple years back. You could try a smoke test for induction leaks

Few warm days and the CEL for P0422 disappeared. The CEL returned today when ambient temp dropped below 77ºF. I can forecast CEL.
I'll plug in VIDA to narrow down location for this vacuum leak, if you say.

Post by **RickHaleParker** » 15 Sep 2019, 19:47

xHeart wrote: 15 Sep 2019, 18:29 Few warm days and the CEL for P0422 disappeared. The CEL returned today when ambient temp dropped below 77ºF.

Metal contracts when cold and expands at higher temperatures.
Spray some Either around the intake manifold when the engine is below 77ºF see if the engine surges. Or you could do a smoke test when the engine is below 77ºF.

Post by **xHeart** » 17 Sep 2019, 07:59

RickHaleParker wrote: 15 Sep 2019, 19:47
xHeart wrote: 15 Sep 2019, 18:29 Few warm days and the CEL for P0422 disappeared. The CEL returned today when ambient temp dropped below 77ºF.
Metal contracts when cold and expands at higher temperatures.
Spray some Either around the intake manifold when the engine is below 77ºF see if the engine surges. Or you could do a smoke test when the engine is below 77ºF.

I'll check it.
FWIW, the intake was taken off during a PCV project, more here viewtopic.php?f=9&t=61449. Then reassembled back with Volvo gasket and new screws.