P2404 - Evaporative Emission (EVAP) Leak Detection Pump Sense Circuit Range/Performance
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System
Powertrain (Engine & Gearbox)
OBS!This code is in a manufacturer-specific range. The description may vary depending on the vehicle manufacturer.
Related Fault Codes
Technical Description
P2404 is set when the Engine Control Module (ECM) detects an implausible signal from the Evaporative Emission (EVAP) Leak Detection Pump (LDP) pressure switch or position sensor. The system utilizes the LDP to pressurize or create a vacuum in the fuel system to monitor for hydrocarbon leaks. If the sensor signal fails to toggle or stays outside expected voltage parameters (typically 0.5V to 4.5V) during the pump's duty cycle, the ECM triggers this code, indicating a circuit performance issue rather than a confirmed physical leak.
Possible Causes
Faulty Leak Detection Pump (LDP) or integrated pressure switch
Damaged or corroded LDP connector
Clogged EVAP system fresh air filter or blocked pump hose VIDA.
Wiring issues (high resistance or short to ground in signal wire)
Faulty Engine Control Module (ECM) software
Symptoms
Recommended Solution
- Visual Inspection: Check the LDP and connector for corrosion. Inspect EVAP hoses and the vent filter for blockages or cracks.
- Voltage Test: Verify 12V power supply and ground at the LDP. Measure the signal voltage; it should typically sit near 0V or 5V at rest (brand specific).
- Bi-directional Test: Use a scan tool to command the pump ON/OFF and monitor the sensor voltage sweep. Verify the duty-cycle matches factory specs.
- Resistance Test: Check the signal wire from LDP to ECM for high resistance (should be < 0.5 Ohms).
- Component Replacement: If the pump functions mechanically but the sensor signal is static, replace the Leak Detection Pump.
Mechanic's Tip
Before replacing expensive components, always double-check wiring and connections. 80% of all sensor faults are actually due to corroded contacts or broken wires.
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