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Need Help: o2 Sensor, P0430 Code, Catalytic Converter Mess

11531 Views 8 Replies 5 Participants Last post by  rclark
Hey everyone, first off thanks in advance for any help or advice anyone can provide. I have searched and read a lot already and I guess am just looking for any advice or opinions before I go get porked by a repair shop if I don't need to.

Was driving home yesterday and my check engine light came on. Went to Auto Zone, they ran their little cpu on it and returned the code P0430.

From what I have gathered this could mean 1 of 2 things.

1. I need a new catalytic converter. I am at 7 years and 96k so I am screwed on the warranty.

2. Bad o2 Sensor(s).

I guess my question is, should I try replacing all my o2 sensors before I take it into a shop, pay $120 for a diagnostic that tells me to spend another $200 on o2 sensors, or tells me I need to drop $600+ on a new cat converter?

Or just replace them myself, see if the check engine light goes off and skip the diagnostic?

If replacing them myself, does anyone know which one(s) to start with? and is this Mopar 56029049AA Oxygen Sensor: Automotive is what I need?

I am not an auto repair guru and don't know much about o2 sensor(s). Are they all the same? Or are there different ones depending on which one you need to change?

At the end of the day, I am jsut trying to not get ripped off while trying to fix this issue. Any advice is appreciated.

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Anyone recommend a website for factory parts? The diagnostic says I need a new cat converter. $1600 quote for the parts and install.

Kick in the nuts.
Check a vendor here on the forum. Moparonlineparts.

Bob K.
Google spark plug non fouler trick. I've done this on my wife's Mustang GT with an off-road pipe, two years now I've not had to remove the off-road pipe to get an inspection. The non foulers stay on permanently and I just remove the tune and let the computer reset before the inspection. This trick could alleviate you from having to replace the cat and not have the CEL light on.
I am not worried about an inspection, I am worried about f%^&ing up my Jeep. I am gonna replace the cat converter, just trying to get the best price.

Special Tools: Click to display a list of tools used in this procedure

Click here to launch the form to order any tools you need.

8815A - Kit, NGC, 38 Position

Originally Shipped In Kit Number(s) 8718, 8718CC, 8815A.8404-EC - Exhaust Cone8404-ECT - Exhaust Cone, Truck

Originally Shipped In Kit Number(s) 8404-ECT.​

For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation

The State of Change (SOC) catalyst monitor uses the signals from both the upstream and downstream O2 sensors to detect aging of the catalyst. Based on the fact that when a catalyst ages, it loses some of its Oxygen Storage Capacity (OSC). As a result, part of the untreated exhaust gases can breakthrough the catalyst and causes the downstream O2 sensor to deviate from its neutral (Stoichiometric) position. By observing the activities in the downstream O2 signal, the degradation level of catalyst can be detected. In general, the higher the downstream O2 sensor SOC value, the more exhaust gas breakthrough and the lower the OSC of the catalytic converter.

  • When Monitored: ECT above 70° C (158° F), engine RPM between 1400 and 2300, vehicle speed between 64 and 96 kph (40 and 60 mph), and engine run time greater than three minutes.
  • Set Condition: If the final State of Change index is within the calibrated fail threshold. Two trip fault. Three good trips to turn off the MIL.
Possible Causes

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


NOTE:A new rear O2 Sensor along with an aging front O2 Sensor may cause the DTC to set. Review the repair history of the vehicle before continuing.
NOTE:If an O2 Sensor DTC set along with the Catalytic Converter Efficiency DTC diagnose the O2 Sensor DTC(s) before continuing.
NOTE:Check for contaminants that may have damaged the O2 Sensor and Catalytic Converter: contaminated fuel, unapproved silicone, oil and coolant, repair necessary.1.Start the engine.2.Allow the engine to reach normal operating temperature.3.With a scan tool, select View DTCs.
NOTE:It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

Some info from the manual. Did you bang on the converter with a soft hammer? Sometimes when a converter goes bad you will hear the honey comb inside ratteling around. If you replace the converter it is a good idea to replace the O2 sensors also.
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Check to make sure your exhaust-manifold is not cracked. Had the same issue with my 08. O2 sensor failed then a day later the catalytic converter. Dealer would not replace the cat without replacing the manifold. One good thing is that I'm not adding a quart of oil every 1000 miles anymore.
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