Evaporative Emission System Leak Detection Pump Sense Circuit Intermittent/Erratic
Diagnostic trouble code P2407 indicates that the powertrain control module (PCM) has detected an intermittent or erratic signal from the evaporative emission (EVAP) system leak detection pump sense circuit. This means the voltage signal from the leak detection pump is fluctuating outside of the expected parameters, preventing the PCM from accurately monitoring the EVAP system for leaks.
This code does not affect the drivability or safety of the vehicle. However, it will cause the vehicle to fail an emissions test and should be repaired to ensure proper EVAP system function.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Failed emissions test
- Slight fuel odor in some cases
- No noticeable drivability issues
- Inability of the PCM to run EVAP readiness monitors
Likely causes
- Faulty EVAP leak detection pump
- Loose, corroded, or damaged wiring in the leak detection pump circuit
- Poor electrical connection at the leak detection pump connector
- Vacuum leak in the EVAP system near the pump
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Visually inspect the wiring and connector at the EVAP leak detection pump.
Look for: Look for frayed wires, corrosion, bent pins, or a loose connector that could cause an intermittent electrical connection.
Check the leak detection pump connector for proper voltage and ground.
Look for: Using a multimeter, verify that the pump is receiving the correct reference voltage and has a solid ground according to the manufacturer's wiring diagram.
Test the leak detection pump sense circuit for continuity.
Look for: Disconnect the PCM and pump connectors, and measure the resistance of the sense wire. High resistance or an open circuit indicates a wiring fault.
Perform a component test on the EVAP leak detection pump.
Look for: Apply the specified voltage or use a bidirectional scan tool to command the pump on, checking if it operates smoothly without erratic current draw or signal dropouts.
Inspect the EVAP hoses connected to the leak detection pump.
Look for: Check for cracks, blockages, or disconnected hoses that might cause the pump to operate erratically or fail to build pressure.
This page explains the generic P2407 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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