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Home >> Chrysler >> 2003 >> Intrepid ES, 3.5 V >> Repair and Diagnosis >> External Pages >> Different car >> Section 5 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0420: Catalytic 1/1 Efficiency Or DTC P0432: Catalytic 2/1 Efficiency >> Testing

DTC P0420: Catalytic 1/1 Efficiency Or DTC P0432: Catalytic 2/1 Efficiency: Testing

WARNING: This page is about a different car, the 2002 Dodge Intrepid, 2002 Chrysler Intrepid, 2002 Chrysler Concorde, and 2002 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE: If an O2 Sensor DTC is also set, diagnose O2 Sensor DTC before proceeding. Also, check for contaminants that may have damaged HO2S and catalytic converter such as contaminated fuel, unapproved silicone, oil and coolant.
  1. Turn ignition on, engine not running. With the DRBIII®, read 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, go to step  7.
  2. Inspect the Catalytic Converter for damage, dents and holes. Check for severe discoloration caused by overheating the Catalytic Converter. Check Catalytic Converter leaks or internal blockage problems. Were any problems found? If yes, replace the Catalytic Converter. Repair the condition that may have caused the failure. If no, go to next step.
  3. Start engine and allow the engine to idle. Check for exhaust leaks between engine and appropriate downstream O2 Sensor. Are there any exhaust leaks? If yes, repair or replace leaking exhaust parts as necessary. If no, go to next step.
  4. Check exhaust for excessive smoke caused by internal oil or coolant 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.
    5. NOTE: A new Downstream O2 Sensor used along with an aging Upstream O2 Sensor may cause this DTC to set.
  5. 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.
  6. There are no possible causes remaining, replace the Catalytic Converter.
    7. 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.
  7. The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. A new Downstream O2 Sensor used along with an aging Upstream O2 Sensor may cause this DTC to set. Review vehicle repair history. Check for contaminants that may have damaged the O2 Sensor and Catalytic Converter such as contaminated fuel, unapproved silicone, oil and coolant. With the engine running at normal operating temperature, monitor the DRBIII® parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII® Freeze Frame information. If possible, try to duplicate the conditions under which the DTC was set. Refer to any Technical Service Bulletins (TSB) that may apply. Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.
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