Evaporative Emission System Leak Detection Pump Control Circuit High
Diagnostic trouble code P2402 indicates that the powertrain control module (PCM) has detected an unexpectedly high voltage signal in the evaporative emission (EVAP) leak detection pump control circuit. This typically means there is a short to power or an open circuit preventing the pump from operating correctly to test the EVAP system for leaks.
This code primarily affects the vehicle's emissions system and will not cause drivability issues. However, it will cause the vehicle to fail an emissions test and should be repaired to ensure proper EVAP system monitoring.
Common symptoms
- Illuminated Check Engine Light
- Failed emissions test or inspection
- Incomplete EVAP system readiness monitor
- Possible faint fuel odor near the rear of the vehicle
- No noticeable drivability or performance issues
Likely causes
- Faulty EVAP leak detection pump (LDP)
- Short to voltage in the LDP control circuit wiring
- Open circuit or poor electrical connection in the LDP harness
- Faulty leak detection pump relay (if equipped)
- Corroded or damaged pins at the LDP connector
- Internal failure of the Powertrain Control Module (PCM)
What to check before replacing parts
Visually inspect the wiring harness and connector at the EVAP leak detection pump.
Look for: Look for chafed wires, melted insulation, or corroded pins that could cause a short to voltage or an open circuit.
Use a bidirectional scan tool to command the leak detection pump on and off.
Look for: Listen for a click or pump operation; if the pump does not activate, the circuit or pump is faulty.
Measure the voltage at the leak detection pump connector with the key on.
Look for: Check if battery voltage is constantly present on the control circuit when it should be off, indicating a short to power.
Test the internal resistance of the leak detection pump using a multimeter.
Look for: Compare the resistance reading to the manufacturer's specifications; an out-of-limits reading (often an open circuit) indicates a failed pump.
Test the continuity of the control wire between the pump connector and the PCM.
Look for: A lack of continuity indicates a broken wire, while continuity to power indicates a short in the harness.
This page explains the generic P2402 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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