P2402 - Evaporative Emission System Leak Detection Pump Control Circuit High
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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
Evaporative Emission (EVAP) Leak Detection Pump Control Circuit/Open
Evaporative Emission System Leak Detection Pump Control Circuit Low
Evaporative Emission System Leak Detection Pump Sense Circuit Open
Evaporative Emission (EVAP) Leak Detection Pump Sense Circuit Range/Performance
Technical Description
The P2402 Diagnostic Trouble Code (DTC) indicates that the Engine Control Module (ECM) has detected a 'high' voltage condition in the Evaporative Emission (EVAP) Leak Detection Pump (LDP) control circuit. This signal is typically interpreted as a short to voltage. The LDP is used to pressurize or create a vacuum within the EVAP system to verify its integrity and detect leaks. When the ECM commands the pump OFF but still perceives a high voltage on the signal return line, or when the current draw exceeds OEM specifications, P2402 is stored. This affects the vehicle's ability to perform self-diagnostic EVAP leak tests.
Possible Causes
Short to voltage in the Leak Detection Pump wiring harness
Failed Leak Detection Pump (internal electrical short/low resistance)
Corrosion or short circuit in the electrical connector (moisture ingress)
Faulty Engine Control Module (ECM) internal driver circuit
Symptoms
Recommended Solution
- Visual Inspection: Examine the wiring harness and connector at the Leak Detection Pump (usually located near the fuel tank or charcoal canister). Look for chafing or corrosion.
- Fuse Check: Inspect all fuses related to the EVAP/Engine management system.
- Electrical Testing: Disconnect the pump connector. Measure voltage on the control wire with ignition ON. If 12V is present when the pump is commanded OFF, there is a short to voltage in the harness. Measure the pump's internal resistance; a value near 0 Ohms indicates an internal short (typical range is 10-50 Ohms depending on vehicle model).
- Bi-directional Test: Use a scan tool to command the pump ON/OFF and monitor the circuit status and current draw.
- Component Replacement: If the wiring is verified as good but the code persists, 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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