DTC P0420: 1/1 Catalytic Converter Efficiency Or DTC P0432: 2/1 Catalytic Converter Efficiency: Testing
WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition on, with engine off. With the DRBIII(R) scan tool, read the DTCs and record the related freeze frame data. Is the Good Trip Counter displayed and equal to zero? If yes, go to next step. If no, see INTERMITTENT CONDITION under SELF-DIAGNOSTIC SYSTEM.
- Inspect the catalytic converter for damage. Check for dents and holes, severe discoloration caused by overheating the catalytic converter, catalytic converter broken internally or leaking catalytic converter. Were any problems found? If yes, replace the catalytic converter and repair the condition that may have caused the failure. If no, go to next step.
- Start the engine and let idle. Check for exhaust leaks between the engine and the downstream O2 sensor. Are there any exhaust leaks? If yes, repair or replace exhaust parts as necessary. If no, go to next step.
- Check exhaust for excessive smoke caused by coolant entering combustion chambers or high oil consumption. Is there an oil or coolant consumption condition present? If yes, repair engine mechanical condition as necessary and replace catalytic converter. If no, go to next step.
- Turn ignition off. Review vehicle repair history. Has the downstream O2 sensor been replaced without replacing the upstream O2 sensor? If yes, replace the appropriate upstream O2 sensor. If no, go to next step.
- If there are no possible causes remaining, replace catalytic converter.
WARNING:
When the engine is operating, DO NOT stand in a direct line with the fan. DO NOT put your hands near the pulleys, belts or fan. DO NOT wear loose clothing.
NOTE:
A new downstream O2 sensor along with an aging upstream O2 sensor may cause this DTC to set.