1999 C2 Error Codes P0430, P1276, and P0159

[auto-xr]

Just checking to see if anyone can help chime in on some error codes I've been getting. I've reset the computer multiple times but the same error codes seem to come up.

P0430 Catalyst system efficiency below threshold bank2

P1276 Aging of Oxygen Sensor Ahead of Catalytic Converter (Cylinders 4 - 6) - Below Lower Limit

P0159 Porsche fault code 23 - 02 sensor ageing behind cat. c. bank 2

From the looks of it, I think that I should change the front and rear O2 sensors for bank 2 and see what happens. Thoughts?

[Loren]

P0430 Catalytic Converter Conversion Too Low (Cylinders 4 - 6)

Probable cause:

TWC

P0159?

How about P0158

P0158 Oxygen Sensor After Catalytic Converter (Cylinders 4 - 6) - Short Circuit to B+

Probable cause:

- Wiring harness

- Oxygen sensor

- DME control module

P0133 Aging of Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Below Lower Limit

Probable cause:

- Oxygen sensor

Very odd. These faults say the O2 sensor ahead of the cat on bank 1 is bad -- and -- the O2 sensor on bank 2 after the cat is bad.

I would check the wiring on all the O2 sensors and verify that it is not broken or corroded. Visually inspect the O2 sensors for damage or signs that some oil (or other substance) has gotten on the sensors.

Then (and only then) would I replace the affected sensors. Reset the codes and see if the bad TWC comes back.

[auto-xr]

P0430 Catalytic Converter Conversion Too Low (Cylinders 4 - 6)

Probable cause:

TWC

P0159?

How about P0158

P0158 Oxygen Sensor After Catalytic Converter (Cylinders 4 - 6) - Short Circuit to B+

Probable cause:

- Wiring harness

- Oxygen sensor

- DME control module

P0133 Aging of Oxygen Sensor Ahead of Catalytic Converter (Cylinders 1 - 3) - Below Lower Limit

Probable cause:

- Oxygen sensor

Very odd. These faults say the O2 sensor ahead of the cat on bank 1 is bad -- and -- the O2 sensor on bank 2 after the cat is bad.

I would check the wiring on all the O2 sensors and verify that it is not broken or corroded. Visually inspect the O2 sensors for damage or signs that some oil (or other substance) has gotten on the sensors.

Then (and only then) would I replace the affected sensors. Reset the codes and see if the bad TWC comes back.

Hi Loren,

Thanks for your feedback. I double checked the Durametric codes and I definitely have a P0159 and P1276. I also ran it against the following link:

http://forums.rennlist.com/rennforums/996-forum/489609-info-sources.html

The P0430 was taken with my ODBCII scan tool however just recently.

The P0159/P1276 combination were both taken at 3 to 4 different intervals during the past year. Is it possible that the Bank 2 pre-cat, twc, and post-cat are all bad?

[Loren]

Sorry, I misread your model year.

P1276 Aging of Oxygen Sensor Ahead of Catalytic Converter (Cylinders 4 - 6) - Below Lower Limit

Probable cause:

- Oxygen sensor

P0159 Aging of Oxygen Sensor After Catalytic Converter (Cylinders 4 - 6)

Probable cause:

- Oxygen sensor

Replace the O2 sensor on bank 2 ahead of the cat.

Your CEL was on solid not flashing correct?

[auto-xr]

Sorry, I misread your model year.

P1276 Aging of Oxygen Sensor Ahead of Catalytic Converter (Cylinders 4 - 6) - Below Lower Limit

Probable cause:

- Oxygen sensor

P0159 Aging of Oxygen Sensor After Catalytic Converter (Cylinders 4 - 6)

Probable cause:

- Oxygen sensor

Replace the O2 sensor on bank 2 ahead of the cat.

Your CEL was on solid not flashing correct?

Hi Loren,

Thanks for the update. I'll order a pre cat O2 sensor for bank 2 and see what happens. Hopefully, that'll take care of the problem. I'll keep the board posted.

[judgejon]

might be good to replace the set while your at it.

good luck 

[DBJoe996]

Ummm...hopefully after almost 8 years (auto-xr last post on December 20, 2010) he figured it out. 

[judgejon]

Right.  2010 indeed.  

Good to read the fine print.  

Cheers, 

[george orwell]

Now, in 2020, I (a different poster) have the same problem. And the advice is helpful. Thanks.