P0420, P0430 codes. Check engine light came on and I scanned and came up with those codes.

[MustangSteve1965]

Scanner says P0420 Catalyst System Efficiency below Threshold (Bank 1) and P0430 Catalyst System Efficiency below Threshold (Bank 2).

Does this mean I need new cats?

Exhaust leak?

I'm taking my car to Alternative Auto Performance on Monday the 24th, is it possible the tune isn't correct and that's what's causing it?

 

[Vinnie_B]

DTC sets when bank 1/2 catalyst system efficiency is below the acceptable threshold.

Possible causes for P0420/P0430 DTC to set:

• Damaged heated oxygen sensor (HO2S)
• Exhaust leaks
• Damaged exhaust manifold
• Damaged catalytic converter
• Oil contamination
• Cylinder misfiring
• Downstream HO2S wires incorrectly connected
• Damaged exhaust system pipe
• Damaged muffler/tailpipe assembly
• Evaporative emission (EVAP) purge valve stuck open
• Leaking fuel injector

Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which reduces the frequency and amplitude of the downstream HO2S as compared with an upstream HO2S signal. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal has an increased amplitude and frequency, approaching the amplitude and frequency of the upstream HO2S.


*For vehicles with universal HO2S, the PCM compares the signal line length of the downstream HO2S to an expected signal line length of the downstream HO2S with a deteriorated catalytic converter.


*For all others, the signal line lengths of the downstream HO2S are compared against the signal line lengths of the upstream HO2S.

 

[MustangSteve1965]

DTC sets when bank 1/2 catalyst system efficiency is below the acceptable threshold.

Possible causes for P0420/P0430 DTC to set:

• Damaged heated oxygen sensor (HO2S)
• Exhaust leaks
• Damaged exhaust manifold
• Damaged catalytic converter
• Oil contamination
• Cylinder misfiring
• Downstream HO2S wires incorrectly connected
• Damaged exhaust system pipe
• Damaged muffler/tailpipe assembly
• Evaporative emission (EVAP) purge valve stuck open
• Leaking fuel injector

Under normal closed loop fuel conditions, high efficiency catalysts have oxygen storage which reduces the frequency and amplitude of the downstream HO2S as compared with an upstream HO2S signal. As catalyst efficiency deteriorates, its ability to store oxygen declines and the downstream HO2S signal has an increased amplitude and frequency, approaching the amplitude and frequency of the upstream HO2S.


*For vehicles with universal HO2S, the PCM compares the signal line length of the downstream HO2S to an expected signal line length of the downstream HO2S with a deteriorated catalytic converter.


*For all others, the signal line lengths of the downstream HO2S are compared against the signal line lengths of the upstream HO2S.

Thanks Vinnie.

I believe it may be:

• Evaporative emission (EVAP) purge valve stuck open

As previously I threw a P0443 Code

Should I just take it to the dealer?

I'm taking it to Lidio at Alternative on Monday the 24th to get it tuned.

Is it best to get this corrected first?

Thanks for all your help!

 

[Vinnie_B]

Thanks Vinnie.

I believe it may be:

• Evaporative emission (EVAP) purge valve stuck open

As previously I threw a P0443 Code

Should I just take it to the dealer?

I'm taking it to Lidio at Alternative on Monday the 24th to get it tuned.

Is it best to get this corrected first?

Thanks for all your help!

P0443 - Evaporative Emission System Purge Control Valve Circuit


The PCM monitors the state of the EVAPCP circuit output driver. This DTC sets when the signal moves outside the minimum or maximum limit for the commanded state.

Possible causes:

• VPWR circuit open
• EVAPCP circuit open
• EVAPCP circuit short to ground
• EVAPCP circuit short to voltage
• Damaged EVAP purge valve
• Damaged PCM

To verify normal function, monitor the EVMV PID or EVAPCP PID and the signal voltage (PCM control side). With the valve closed, the EVMV indicates 0 mA (0% duty cycle for EVAPCP) and voltage approximately equal to battery voltage. When the valve is commanded fully open, EVMV indicates 1,000 mA (100% duty cycle for EVAPCP) and a voltage drop of 3 volts minimum is normal.



Yea I would get this checked out first @MustangSteve1965. You have low mileage and cant see the CATS going bad so soon.

 

[MustangSteve1965]

P0443 - Evaporative Emission System Purge Control Valve Circuit


The PCM monitors the state of the EVAPCP circuit output driver. This DTC sets when the signal moves outside the minimum or maximum limit for the commanded state.

Possible causes:

• VPWR circuit open
• EVAPCP circuit open
• EVAPCP circuit short to ground
• EVAPCP circuit short to voltage
• Damaged EVAP purge valve
• Damaged PCM

To verify normal function, monitor the EVMV PID or EVAPCP PID and the signal voltage (PCM control side). With the valve closed, the EVMV indicates 0 mA (0% duty cycle for EVAPCP) and voltage approximately equal to battery voltage. When the valve is commanded fully open, EVMV indicates 1,000 mA (100% duty cycle for EVAPCP) and a voltage drop of 3 volts minimum is normal.



Yea I would get this checked out first @MustangSteve1965. You have low mileage and cant see the CATS going bad so soon.

Thanks again Vinnie!

Man, I'm really hoping I didn't buy a lemon here. Hopefully, I'm overreacting.

Going to reschedule with Lidio and take it to the dealer. Wife is going to be oh so happy that I spend $55K on a car and have to take it to the dealer again.

 

[MustangSteve1965]

Thanks again Vinnie!

Man, I'm really hoping I didn't buy a lemon here. Hopefully, I'm overreacting.

Going to reschedule with Lidio and take it to the dealer. Wife is going to be oh so happy that I spend $55K on a car and have to take it to the dealer again.

Doing more research, it seems if there is an off road X pipe or high flow cats, that could be causing it since it's both banks.

I texted the guy from whom I bought it to ask if any exhaust/cat mods were done.

Thinking it could be 02 sensors.