P2406 OBD Error Code: Problem & Solutions

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An EVAP leak is a fault in the evaporative emission control system (EVAP). The EVAP’s function is to keep gasoline fumes in the fuel tank from reaching the atmosphere. This keeps air pollution down and keeps the smell of fuel from reaching the inside of your vehicle. Fuel vapors are emitted from vehicles any time there is gasoline in the tank. So if you have a leak, even if you are not driving the vehicle, those vapors are polluting the air 24 hours a day. Uncontrolled emissions like this account for about 20 percent of the pollution produced by vehicles.

OBD code P2406 means Evaporative Emission System Leak Detection Pump Sense Circuit High Issue.

The charcoal canister contains charcoal which absorbs and stores the fuel vapours. When the time comes to “purge” the vapours, fresh air passes over the charcoal and this releases the vapours. When engine operating conditions are correct, the purge solenoid opens the purge valve. This allows fuel vapours to be sucked into the engine and burned.

Enhanced EVAP systems use a canister vent solenoid and valve during system self-testing. The PCM closes the valve, sealing the canister off from outside air. Then, the PCM can monitor the closed system and check it for leaks. Once the engine is shut down, the powertrain control module (PCM) tests the integrity of the EVAP system. It does this by closing off the system and monitoring pressure/vacuum to check for leaks. Code P2406 indicates the PCM has detected high voltage output in the leak detection pump circuit indicating low power to the pressure sensor.

What causes this problem with the Evaporative Emission System Leak Detection Pump Sense Circuit High?

• EVAP pump sense circuit shorted
• Corroded or damaged connection to the leak detection pump
• Faulty wiring of the exhaust system to the PCM/ECM

1. Engine Control Module – ECM faults are rare but can be a big problem as faulty ECM will cause wrong vehicle operations and can also result in wrong OBD codes getting stored in the system which can also cause misdiagnosis. Thus, replace faulty ECM components now!
2. Electronic Control Unit – The ECU coordinates with the temperature sensor to control the blower fan for keeping the battery temperatures under control. So, replace faulty ECU components now!
3. Exhaust Gas Recirculation Valve - Did you just see check engine light flashing on your dashboard? If the computer would detect some fault with the automobile’s EGR valve circuit, then it would set up the check engine light so that the driver is notified about the fault. Don’t waste time and get them replaced or else this fault code can turn up.
4. Fuel Injector - Faulty fuel injector, it will cause rough idles and difficulty in starting. Also, it will affect the fuel economy and engine performance. Fuel injector can also crack or break leading to leakages and should be replaced immediately.
5. Diesel Exhaust Fluid Pump - The diesel exhaust fluid pump needs to work properly if the transmission system has to perform. If it is not functioning, the transmission may slip and cause harsh shifts too. Thus replace faulty pump now and buy a new one from us!
6. Powertrain Control Module – Check for PCM error which might be due to circuit faults that might require complete replacement and reprogramming. Replace it now!
7. Oxygen Sensor – Inspect for faulty O2 sensor that can affect the engine combustion process and the exhaust emissions. Thus, it is important to understand its importance and replace faulty oxygen sensor now!
8. Manifold Absolute Pressure Sensor - The MAP sensor would fail by getting clogged, contaminated, or sometimes damaged. There can be times when the engine heat would “overcook” the electronics of the MAP sensor and can cause cracks vacuum lines. So it is very important to take proper care of the MAP sensor and in case you need a new one, then Parts Avatar is here at your service.
9. Diagnostic Tool - In order to detect the error, one needs high grade diagnostic tools. Visit us today to grab amazing deals.
10. EVAP Leak Detection Pump - Basically a leak in the EVAP system will make the LDP keep pumping, since there is an escape for the air pressure. It is precisely the job of the LDP to detect such leaks. A vacuum problem to the upper chamber will render the LDP inoperative. The atmospheric line can actually be broken without affecting the system. In this case, the LDP will suck air through it instead of the LDP air filter.
11. Vapor Canister Valve - If your canister purge valve is stuck open, however, it creates a vacuum leak that can affect your engine adversely. Simply put, air will be allowed to enter the engine in a quantity that is not predicted by your car’s computer. This will change the car’s air to fuel ratio, and can cause rough idling (car feels rough and bouncy when the engine is running), as well as difficulty starting. If experienced in tandem, there is a high likelihood of a failing canister valve, or some other part of the EVAP system.
12. Vapor Canister Purge Solenoid - A defective canister purge solenoid may also set off the Check Engine Light. If the computer detects any problem with the purge solenoid circuit or signal, it will set off the Check Engine Light to alert the driver that a problem has occurred. A Check Engine Light can also be caused by a wide variety of other problems, so it is recommended to have the vehicle scanned for trouble codes to be sure.

For us our customers are everything, and that’s why we will help you to diagnose P2406 code by mentioning some important symptoms below:

Common Symptoms

• Affected fuel economy
• Increased exhaust emissions
• Check engine light ON
• Rough engine idles
• In rare cases, complete engine failure

After you know the symptoms of your vehicle’s problem, it becomes easy to detect it and get started with solving it. So, next on our list is few common steps to correct this issue with your vehicle.

• Faulty wiring repair or replacement
• EVAP pressure sensor repair or replacement
• Fuel cap replacement
• Faulty EVAP valves replacement
• EVAP pump circuit and connections corrections

To do all this, you will need few high quality auto parts such as ECM, EVAP, PCM, EVAP System, Intake Manifold, Evap Pump and so on. From where will you get them? From your local store? Well, why go there when you can order quality parts with us while sitting in the comfort of your home. So, just browse through our website and order your needed parts today.

Here are some steps which you should follow in order to diagnose this fault code P2406:

Scan codes and document the code in the PCM, view the freeze frame data to see when fault happened. Inspect the entire vapour purge valve system to include the purge valve and vent valve hose connectors for damaged or loose connections

Check the purge valve vent for any blockage from dirt, debris or spider webs that could cause the valve to not be able to complete a total seal of the vapours. Perform a smoke leakage test on the fuel vapour system to try and locate the cause of the vapour leak using the test vapour port, checks the fuel cap for vent leakage

Inspect the EVAP pump for any problems in association to the circuit wiring and connectors and resolve them immediately.

Check the purge control valve to see if it will hold a vacuum when activated. Also check for faults in the PCM and repair or reprogram as required.

Common Mistakes When Diagnosing the P2406 Code

Not checking and assuming the EVAP pump is defective without doing a thorough diagnostics of the complete system to later find the wiring is broken or cut, not verifying the leak and replacing parts that may or may not be the problem, and not checking for any technical service bulletins that may have a fix for the code are some of the common mistakes.