eko1

I was just reading the O2 sensor thread and was wondering what codes you guys were getting?

I put on some shorty headers a couple of months ago. Last week I had the codes P0422 and P0432 come up at the same time. The description for the codes is "Main Catalyst Efficiency Below Threshold".

I think it would be unusual that both bank 1 and 2 primary cats to fail at the same time. I am wondering if this could be due to bad O2 readings?

Anybody have these codes?

Are these the codes that tuners are tuning out by manipulating the O2 sensors?

Thanks.

jmb614

If you removed the primary cats then that is likely the reason you are seeing those codes. The ECU thinks the cats aren't doing their job; if you've removed them, the ECU is correct

eko1

Thanks.

I should have stated that. The cats were not removed.

jmb614

http://www.obd-codes.com/p0422

eko1

Thanks 614.

I looked up the codes and am aware of what they mean.

Has anybody else had these codes?

Are these the ones you get when you remove the cats and the tuners get the CEL to go out?

pearlpower

I have had shorties on for some time along with deleted secondaries and 200 cell primaries. I received those codes just recently, the only time. Not sure why it took so long to kick on but will be monitoring it. Easily pulled and uploaded to Dropbox for storage and cleared as I keep the ELM327 plugged in at all times. I realize 300 cell cats would have most likely held off codes, but the 200 cells were enticing. LOL.

Fault log report generated by Torque for Android
=================================================
Vehicle VIN:
Vehicle Manufacturer: Mercedes-Benz

Vehicle Calibration ID: Not present

Current
Fault Log
------------------

P0432: Main Catalyst Efficiency Below Threshold (Bank 2)

P0422: Main Catalyst Efficiency Below Threshold (Bank 1)

Pending Fault Log
------------------
ECU reports no pending faults

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------

ECU reports no other fault codes logged

End of report.