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P2423 is a diagnostic trouble code (DTC) for "HC Adsorption Catalyst Efficiency Below Threshold Bank 1". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
A P2423 code is a generic powertrain code related to emissions systems problems. In this case, the hydrocarbon adsorption and catalyst efficiency is below the allowed threshold in engine bank 1 (typically the number 1 cylinder).
This code is related to:
The Hydrocarbon Absorptive Catalyst (HCAC) system includes a three-way catalyst and two heated oxygen sensors. The three-way catalyst absorbs hydrocarbons emitted soon after the engine is started.
If a P2423 code appears, engine bank 1 is signaling that its hydrocarbon adsorption and catalyst efficiency is below the allowed threshold. The engine control module (ECM) takes exhaust composition and temperature information from the vehicle’s oxygen sensors and determines the degree of needed catalyst efficiency. If the level detected varies from the necessary amount, a P2423 code will be stored.
A P2423 code is caused by a number of possible problems, including:
Damaged or defective catalytic converter
Damaged or defective oxygen sensors (will typically accompany an oxygen sensor diagnostic trouble code)
Incorrect fuel use
Damaged or defective coolant temperature sensor
Damaged or defective mass air flow sensor
Damaged or defective manifold air sensor
Damaged or defective fuel pressure regulator or fuel injection system/components
Possible leaks from exhaust components upstream from the catalytic converter
A mechanic may use one or more of the following methods to diagnose a P2423 code:
Use an OBD-II scanner to check for a stored P2423 code
Inspect the exhaust system for leaks
Visually inspect all wiring and connectors for damage
Use a temperature gun to measure exhaust pipe temperatures before and after the catalytic converter
Measure upstream and downstream oxygen sensor operations on bank 1 with an oscilloscope
When failures revolving around the catalytic converter occur, one of the most common mistakes include not completely understanding the initial cause of the failure. Engine misfires or rich exhaust levels can cause catalytic converter failure due to deterioration of the platinum. Failing to fix the causes of these issues first can result in unneeded repairs. Oxygen sensor failure should also be checked.
Because a vehicle can stall and possibly go into “limp mode, and operation can become dangerous, YourMechanic considers this a serious code and recommends getting this diagnosed and repaired as soon as possible to protect the car from further damage.
Repairs that can fix a P2423 code can include:
Repairing any leaks in the exhaust system
Repairing or replacing any frayed or shorted wires or damaged connectors
Repairing or replacing any damaged oxygen sensors (Note: an oxygen sensor code should also be stored on the ECM if doing this repair)
Replacing a damaged or defective catalytic converter
Clearing the codes, test driving the vehicle, and rescanning to see if the codes reappear
A catalytic converter failure is typically a sign of additional, serious problems. Problems upstream from the catalytic converter may be read by the ECM as a failure of the catalytic converter, resulting in speedy, unnecessary repairs or replacement of the catalytic converter. Always resolve any oxygen sensor codes before working to fix a catalytic converter code.
In addition, catalytic converters are typically backed by a 100,000-mile federally mandated warranty, so check to see if it is still covered before making repairs.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.