Evaporative Emission System Leak Detection Pump Control Circuit/Open
The Powertrain Control Module (PCM) monitors the electrical circuit of the Evaporative Emission (EVAP) system's leak detection pump. Code P2400 is set when the PCM detects an open circuit or a lack of electrical continuity in this specific control circuit.
This is an emissions-related code that does not typically affect engine performance or drivability. However, it will cause the vehicle to fail an emissions inspection and should be repaired to ensure proper EVAP system monitoring.
Common symptoms
- Illuminated Check Engine Light
- Failed state emissions test
- Incomplete EVAP system readiness monitor
- Possible faint fuel odor near the rear of the vehicle
- No noticeable drivability or performance issues
Likely causes
- Damaged or corroded wiring in the leak detection pump control circuit
- Loose or poor electrical connection at the leak detection pump
- Faulty EVAP leak detection pump
- Blown fuse supplying power to the EVAP system
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Inspect the wiring harness and connector at the leak detection pump.
Look for: Look for broken wires, corrosion, or loose pins that would cause an open circuit.
Check the fuses related to the EVAP system and leak detection pump.
Look for: A blown fuse indicates a short circuit that needs to be traced, which interrupts power to the pump.
Measure voltage at the leak detection pump connector with the key on.
Look for: You should see battery voltage on the power feed wire; a lack of voltage indicates an open circuit upstream.
Test the internal resistance of the leak detection pump using a multimeter.
Look for: Compare the resistance reading to factory specifications; an infinite reading (OL) means the pump's internal coil is open and the pump must be replaced.
Use a bi-directional scan tool to command the leak detection pump on and off.
Look for: Listen for a click or observe the circuit state on the scanner to verify if the PCM can successfully control the pump when commanded.
This page explains the generic P2400 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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