Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer thinks that a special part that helps clean the air from the engine isn't working well on one side of the engine.
The HC Adsorption Catalyst is designed to reduce hydrocarbon emissions. When its efficiency falls below a certain threshold, the engine control module (ECM) triggers this code.
The P2423 code indicates that the efficiency of the hydrocarbon (HC) adsorption catalyst on bank 1 is below the required threshold. This component is responsible for adsorbing hydrocarbons during cold starts to reduce emissions. If it fails to perform adequately, the ECM detects this and sets the code.
• Check Engine Light is on
• Increased emissions
• Possible decrease in fuel efficiency
• Faulty HC adsorption catalyst
• Exhaust leaks
• Faulty oxygen sensors
HC: Hydrocarbon
ECM: Engine Control Module
• Use an OBD-II scanner to confirm the code
• Inspect the HC adsorption catalyst for damage
• Check for exhaust leaks
• Replace the HC adsorption catalyst
• Repair any exhaust leaks
• Replace faulty oxygen sensors
• OBD-II scanner
• Wrench set
• Exhaust leak detector
$500 - $1200
Moderate
• Toyota Camry
• Honda Accord
• Nissan Altima
• Regular vehicle maintenance
• Timely replacement of faulty sensors
• Routine exhaust system inspections
Emission Control Issue
• Have your vehicle inspected by a professional
• Avoid driving the vehicle excessively until repaired
Check with the vehicle manufacturer for warranty coverage on emission-related components.
This code has become more common as emission standards have tightened and vehicles age.
Moderate – While the vehicle may still be drivable, increased emissions can lead to further damage.
Driving with this code may result in failing emissions tests and could lead to fines in areas with strict emissions regulations.
• Vehicle at operating temperature
• Engine running at idle
The HC adsorption catalyst is typically located in the exhaust system, close to the engine.
Q: Can I drive with a P2423 code?
A: It's possible, but not recommended due to increased emissions and potential further damage.
Q: How do I know if my HC adsorption catalyst is bad?
A: A mechanic can perform tests to determine if the catalyst is functioning properly.
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Fitment Required · Vehicle-fitment part
Relevant when the code or supporting diagnostics point toward upstream or downstream oxygen-sensor faults.
This code family often involves upstream or downstream oxygen-sensor diagnosis.
Verify exact sensor position and vehicle fitment before buying.
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Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.