P0420- Catalyst System Efficiency Below Threshold Bank 1
Possible Causes: - Three way catalyst converter Bank 2 - Exhaust tube - Intake air leaks - Fuel injectors may be faulty - Fuel injector leaks - Spark plugs may be faulty - Improper ignition timing - Engine Control Module
Possible Solutions: The most common cause is the three way catalyst converter Bank 1. Changing just the O2 sensor usually don't repair the problem.
A three way catalyst converter(Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst (Manifold) malfunction is diagnosed.
Answers & Comments
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Code p0420 means Catalyst System Efficiency Below Threshold (Bank 1). This will surely needs attention to resolve the problem.
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P0420- Catalyst System Efficiency Below Threshold Bank 1
Possible Causes:
- Three way catalyst converter Bank 2
- Exhaust tube
- Intake air leaks
- Fuel injectors may be faulty
- Fuel injector leaks
- Spark plugs may be faulty
- Improper ignition timing
- Engine Control Module
Possible Solutions:
The most common cause is the three way catalyst converter Bank 1. Changing just the O2 sensor usually don't repair the problem.
A three way catalyst converter(Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst (Manifold) malfunction is diagnosed.