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P0420 Fault Code in 2001 Dodge Neon: Diagnosis and Solutions

Model: 2001 Dodge Neon Fault Code: P0420 Posted: 2006-08-01 21:37

I have recently replaced both oxygen (O2) sensors and the catalytic converter on my 2001 Dodge Neon. After performing the replacement, I used an OBD-II scanner to reset the system, but the P0420 code reappears. I've tried multiple troubleshooting steps, yet the issue persists. Can anyone provide insight into possible causes or further diagnostic steps for this specific model? 10 Q

Related fault codes
P0420
Comments (2)
Anonymous 2006-08-08 09:53

Please specify the brand of your O2 sensors and catalytic converter. Additionally, check if any fuses are blown in the O2 heater circuit. Also verify the EGR valve operation and inspect fuel pressure levels—these components can contribute to a P0420 code on a 2001 Dodge Neon.

Anonymous 2006-08-09 12:25

I installed dealer-grade O2 sensors, but could not locate an EGR valve. I'm now considering replacing the fuel pressure regulator as well and will also inspect the O2 heater circuit fuses. Thank you for the advice—I'll update this thread so others with similar issues can benefit. kdrram, Houston TX