2008 Saturn Vue 3.6L Automatic
140,000
I have a P0430 code and From what I read I may have to replace my CAT for Bank 2, but not sure since my O2 sensors seem to read as they are supposed to, back pressure test showed good and CAT temp readings looked good also. Just not 100% sure it is my CAT that needs replacing. Any ideas on what else I can check? Not really wanting to change cat if I don’t have to.
Calculated Engine Load Value 43.1 %
Engine Coolant Temperature 205
Short Term Fuel Trim Bank 10.0 %
Long Term Fuel Trim Bank 1-10.2 %
Short Term Fuel Trim Bank 20.0 %
Long Term Fuel Trim Bank 2-7.0 %
Fuel Pressure (Gauge) 43.1 PSI
Intake Manifold Absolute Pressure 13.0 inHg
Engine RPM768 rpm
Vehicle Speed0 MPH
Timing Advance for #1 cylinder9.5 °
Intake Air Temperature 97 °F
Mass Air Flow Rate7.18 g/s
Absolute Throttle Position20.4 %
Run Time Since Engine Start 4581 seconds
Commanded Evaporative Purge0.0 %
Fuel Level Input68.2 %
# of Warm-ups Since Codes Cleared2
Distance Traveled Since Codes Cleared60 mile
Evap. System Vapor Pressure0.292 inHO₂
Barometric Pressure28.9 inHg
Catalyst Temperature Bank 1 - Sensor 11236.2 °
Catalyst Temperature Bank 2 - Sensor 11248.8 °
Control Module Voltage14.268
Absolute Load Value26.3 %
Commanded Equivalence Ratio0.847 λ
Relative Throttle Position7.5 %
Ambient Air Temperature81 °F
Absolute Throttle Position B20.4 %
Accelerator Pedal Position D19.2 %
Accelerator Pedal Position E9.4 %
Commanded Throttle Actuator10.6 %
Your MAF sensor is reading too high for a 3.6 L engine at 768 rpms. It's showing 7.18 g/s. It should be closer to 4 g/s.
LTFT on bank 1 is subtracting 10.2% and LTFT on bank 2 is subtracting 7%. (Probably due to that lying MAF sensor).
Since you say the back pressure looks good you might want to set your scanner to graph the upstream O2 sensor and the downstream O2 sensor voltages on bank 2. You don't want to see that downstream O2 sensor voltage jumping around
Well it takes a professional mechanic to correctly diagnose a cat using freeze frame oscilloscopes a road test and a lot of knowledge. I would advise you to do that rather than just guess because there are literally scores of things that can cause the inefficient cat code to pop up you don't want to waste money on a cat you don't need
Thanks Scotty! I will try to find me a good mechanic here locally to further diagnose.