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P2421 is a diagnostic trouble code (DTC) for "Evaporative Emission System Vent Valve Stuck Open". 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.
The P2421 fault code indicates the vehicle’s on-board computer has detected either the vent valve or vent valve control circuit is stuck open in the evaporative (EVAP) control system, which recovers any raw fuel that may begin to evaporate within fuel storage.
While the P2421 code registers, it indicates a change in fuel pressure due to the EVAP control system allowing raw fuel to evaporate.
Several issues can cause the conditions triggering the P2421 code to register, ranging from a damaged or loose fuel cap to a faulty sensor. These conditions, however, are most frequently caused by a faulty vent valve or vent valve control solenoid.
Aside from the P2421 trouble code registering, it is not likely the vehicle will display any other symptoms, although other fault codes may also be present. Aside from the P2421 trouble code registering and setting the Check Engine Light, it is not likely the vehicle will display any other symptoms, although other fault codes may also be present.
In diagnosing the P2421 OBD-II trouble code, a technician will first validate the presence of the code using a specialized scan tool. This tool retrieves data from the on-board computer and reports any anomalies in the form of trouble codes. Using personal experience and professional reference guides, the technician can narrow the potential causes of the P2421 code and perform a hands-on inspection (possibly using a smoke machine to help identify any leaks), repairing or replacing any parts deemed necessary before performing another scan to ensure the issue is resolved.
After the P2421 trouble code registers, the most common mistakes in troubleshooting it are:
While there are few - if any - symptoms to accompany the P2421 trouble code, neglecting to address the underlying issue can lead to greater problems down the road. It is, therefore, advisable to seek an inspection and make repairs promptly.
After validating the existence of the P2421 fault code, the following repair(s) may be needed:
Often, the underlying issue causing the P2421 code to register is an intermittent one, which can make it difficult to diagnose. An intermittent condition may require extra time to troubleshoot due to the need for multiple tests. In some cases, it may even be necessary to allow the problem to worsen in order to identify the cause. If other trouble codes are present, it may be helpful for the mechanic in diagnosing the root cause of the P2421 code.
YourMechanic can connect you with a mobile technician capable to traveling to you to diagnose your P2421 fault code. Get a quote, book an appointment online, or speak with one of our service representatives at 1-800-701-6230.