P2400 OBD-II Trouble Code: EVAP Leak Detection Pump Control Circuit/Open

Check Engine Light

P2400 code definition

EVAP Leak Detection Pump Control Circuit/Open

What the P2400 code means

Trouble code P2400 is set when the Engine Control Module (ECM) detects a problem on the circuit that controls the evaporative emissions (EVAP) leak detection pump, or ECM is not seeing the expected result when the leak detection pump is activated.

What causes the P2400 code?

There are a few different reasons why P2400 would set:

  • The most obvious would be that the leak detection pump motor has failed. A failure of the pump motor could cause an open or short circuit in the leak detection pump control circuit.

  • Next would be a leak or damage to the hoses that connect the pump to the EVAP system. This would cause a condition where the pump control circuit would be good, but the computer does not see the right reaction from the system.

  • The final problem could be with the wiring or the ECM itself.

What are the symptoms of the P2400 code?

The main symptom for this code is that the Check Engine Light will come on. There are no drivability problems typically associated with this code.

How does a mechanic diagnose the P02400 code?

As with any diagnosis, I recommend a visual inspection of all the components involved in the system that is Malfunctioning. Many times this visual check can save you time and avoid unnecessary diagnostics.

  • Look for broken wires or wires that have rubbed through the insulation. Also look for damage to hoses connected to the leak detection pump.

  • If no visible damage is visible it may be necessary to check the integrity of the hoses in the EVAP system by using a smoke machine to find small cracks or leaking seals.

  • Next, I would use a test light that uses an incandescent headlight bulb to check the power and ground supply to the pump. Disconnect the electrical connector and plug the test light into the terminals of the connector with the appropriate probes. Using a scan tool, command the leak detection pump on. You should see the test light shining very brightly. If it is dim that means there is a fault in the wiring that needs to be located.

If no faults are found in the wiring it may be possible that the power supply from the ECM may be at fault.

Common mistakes when diagnosing the P2400 code

  • As always, the most common mistake is replacing components without performing the correct diagnostics.

  • The next most common mistake would be not identifying a leak in the EVAP hoses that lead to and from the pump.

How serious is the P2400 code?

The P2400 trouble code is not a very serious code. The only problem is that this code will most likely fail you for an emissions test.

What repairs can fix the P2400 code?

  • The most common repair for this trouble code is to replace a faulty leak detection pump.

  • Next would be to repair a broken or leaking hose leading to or from the leak detection pump.

  • Finally, after those repairs, the next most common fix is to repair the wiring leading to the leak detection pump.

Need help with a P2400 code?

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.

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