Code P0430 Cat. Sys. Eff. Below Thresh. Bank 2, '99 5.3

[MotoCARR_]

• 1999 5.3
• I assume original exhaust system at the headers/pre cats but there is a Borla exhaust installed.
• Engine was swapped with a low mile unit but if exhaust matches the body, ~155K
• Actron AutoScanner Plus code reader/scanner

-Check engine light has been on since I purchased the truck a week or so ago. Pulled codes and I had P0300(Random-Multiple Misfire Detected Intermittent) AND P0430(Catalyst System Efficiency Below Threshold Bank 2).

-Started the truck, let it idle for about 5 min, made the video below of the O2 sensor readings. No check engine light.

-Made a 3 mile round trip and on the way back the light came back. This time ONLY P0430.

For the video, from what I can tell:

O2S11= Upstream driver side

O2S12= Downstream driver side

O2S21= Upstream passenger side

O2S22= Downstream passenger side.

Two questions:

1. Based on the code I assume I should be focusing on the O2S22 reading since that is the sensor reading on bank 2 after the cat. correct?
2. These readings were taken after a 5 min idle. Is a longer drive time necessary to get a better or more accurate reading?

https://youtu.be/5o4rsivto8U

[tbarn]

P0430 almost always means replace the converter. Maybe 2% chance it is not. TWC = converter.

 

 

Inspect for the following conditions:

•Verify that the TWC is an original equipment part.
•Inspect the TWC for damage from the following conditions:
– Dents
– Severe discoloration caused by excessive temperatures
– Holes
– Other conditions
•Verify that an internal TWC rattle that is caused by a damaged catalyst is not present.
•Inspect the exhaust system for the following conditions:
◦Leaks
◦Damage
◦Loose hardware
◦Missing hardware
Refer to Exhaust Leakage in Engine Exhaust.

•Verify that the HO2S 1 and the HO2S 2 are secure, and ensure that the pigtails and the wiring are not damaged or contacting the exhaust.

 

If all passes inspection, replace converter