P2421 Code - Evaporative Emission System Vent Valve Stuck Open
Quick Answer
The fuel tank pressure (FTP) sensor output indicates about atmospheric pressure 0 kPa (0 in.Hg, 0 mmHg) before purge starts since the evaporative emission (EVAP) canister vent shut valve is normally open (open to the atmosphere). Common causes include Faulty Evaporative Emission Vent Shut Valve, Evaporative Emission Vent Shut Valve harness is open or shorted, Evaporative Emission Vent Shut Valve circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P2421 indicates Evaporative Emission System Vent Valve Stuck Open.
- Common causes
- Common causes include Faulty Evaporative Emission Vent Shut Valve, Evaporative Emission Vent Shut Valve harness is open or shorted, Evaporative Emission Vent Shut Valve circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P2421 Description
When the FTP sensor indicates vacuum after starting the engine, there is the possibility of an FTP sensor zero point shift failure or an EVAP canister vent shut valve stuck closed failure. So the Powertrain Control Module (PCM) monitors the FTP sensor output after purge starts. The PCM detects a malfunction of the EVAP canister vent shut valve if the output indicates excessive vacuum.
However, if the fuel tank internal pressure is below the specified value (excessive vacuum is detected) when starting the engine, the malfunction detection should be done as follows because it is difficult to distinguish the FTP sensor range problem (P1454) from the EVAP canister vent shut valve stuck closed (P2422).
1. If neither Temporary Diagnostic Trouble Code (DTC) (P1454 nor P2422) is stored, both DTCs are stored.
2. If both Temporary DTCs (P1454 and P2422) are stored and excessive vacuum is detected, both DTCs are stored.
3. If either Temporary DTC (P1454 or P2422) is stored and excessive vacuum is detected, the PCM stores the DTC of the Temporary DTC that was stored.
What are the Possible Causes of the DTC P2421?
- Faulty Evaporative Emission Vent Shut Valve
- Evaporative Emission Vent Shut Valve harness is open or shorted
- Evaporative Emission Vent Shut Valve circuit poor electrical connection
How to Fix the DTC P2421?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P2421 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- P2421 Dodge — Evaporative Emission System Vent Valve Stuck Open
Frequently Asked Questions about P2421 Code
1. What are the common symptoms of OBDII code P2421?
- Common symptoms include the check engine light coming on, decreased fuel efficiency, and potentially a strong gasoline smell.
2. What does the OBDII code P2421 mean?
- The code P2421 indicates that the evaporative emission system vent valve is stuck open, leading to a possible leak in the system.
3. What are the possible causes of code P2421?
- The code P2421 can be caused by a faulty vent valve, a damaged or disconnected vacuum hose, or a malfunctioning purge valve.
4. How serious is OBDII code P2421?
- While the code itself may not cause immediate driving issues, it can lead to increased emissions and decreased fuel efficiency if left unresolved.
5. How can I diagnose a vent valve stuck open issue?
- Diagnosing the issue involves inspecting the vent valve, checking for vacuum leaks, and testing the functionality of related components with a scan tool.
6. Can I continue driving with OBDII code P2421?
- It is generally not recommended to drive with this code active, as it can affect the vehicle's emissions and fuel economy.
7. What is the typical repair for OBDII code P2421?
- The typical repair involves replacing the faulty vent valve, repairing or replacing damaged hoses, and clearing the code with a scan tool.
8. How much does it cost to fix code P2421?
- The cost of fixing code P2421 can vary depending on the cause of the issue, but it typically ranges from $100 to $300 for parts and labor.
9. Can I reset the code P2421 without fixing the issue?
- While you can clear the code with a scan tool, it is important to address the underlying problem to prevent further issues with the evaporative emission system.
10. How can I prevent OBDII code P2421 from recurring?
- Regular maintenance, checking for loose hoses, and addressing any warning signs promptly can help prevent the vent valve stuck open issue from happening again.
Discuss the causes and fixes for P2421 OBDII Code
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