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So I got a CEL on Saturday. I checked the code and it is P0430, which seems to be caused by a bad cat, a bad O2 sensor, or a vacume leak. I know I've got a cracked exhaust manifold. Can the cracked exhaust manifold cause this CEL error code?
 

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Here is some info for the code you have. (Exhaust Leak Is on the list.)

P0430-CATALYST EFFICIENCY (BANK 2)

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 3 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

O2 RETURN UPSTREAM CIRCUIT SHORTED TO GROUND

O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO GROUND

O2 RETURN UPSTREAM CIRCUIT OPEN

O2 RETURN DOWNSTREAM CIRCUIT OPEN

EXHAUST LEAK

ENGINE MECHANICAL CONDITION

AGING O2 SENSOR

CATALYTIC CONVERTER
 

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So I got a CEL on Saturday. I checked the code and it is P0430, which seems to be caused by a bad cat, a bad O2 sensor, or a vacume leak. I know I've got a cracked exhaust manifold. Can the cracked exhaust manifold cause this CEL error code?
Yes... any exhaust leak can cause that type of code... (Tech gurus) tell us anywhere from the manifold down to with 18 inches past the cat...
what happens is during decel, the exhaust sucks in "fresh air" that the PCM didnt see come in or expect to be there and thinks the cat is failed

We test it by plugging the tailpipe and introducing air into it (we use a plarge plug with an air hole for an adjustble air sprayer) NO MORE THAN 5psi ... and spray the entire exhaust system with very soapy water, watch for bubbles..
(i use more than 5 psi to expediate the soap to bubble)... find leaks, repair
i would suggest doing it with a cold system, then heat the engine up to temp, shut off engine and retest...
 
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