Open or damaged wire in the control circuit between the leak detection pump and the engine computer.; Corroded or loose electrical connector at the leak detection pump or at the computer.; Failed leak detection pump solenoid or motor winding, causing an open circuit.; Short to battery voltage in the control wire, often from chafed insulation.; Faulty engine computer driver for the leak detection pump circuit, though this is less common.; Blown fuse or relay that supplies power to the leak detection pump, leading to a high-voltage signal on the control side.

DTC codes / P24xx · Auxiliary emission controls / P2402

P2402Evaporative Emission System Leak Detection Pump Control Circuit High

P2402 means the engine computer has detected an abnormally high voltage on the control circuit for the evaporative emission leak detection pump, which is the component that pressurizes the fuel system to check for leaks. The computer expects to see a switched ground or a duty-cycled signal, but instead it sees voltage that stays too high, indicating an open circuit, a short to power, or a failed pump driver.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms.
A slight fuel odor may be present if the leak detection pump is stuck and not sealing properly.
In some vehicles, the remote start or fuel door release may be disabled as a failsafe.
Rough idle or hesitation only if the high voltage is caused by a shorted pump that drags down the shared power supply.
Inability to complete an emissions readiness monitor, causing a failed inspection.
In rare cases, the pump may run continuously and drain the battery.

Common causes, most likely first

Open or damaged wire in the control circuit between the leak detection pump and the engine computer.
Corroded or loose electrical connector at the leak detection pump or at the computer.
Failed leak detection pump solenoid or motor winding, causing an open circuit.
Short to battery voltage in the control wire, often from chafed insulation.
Faulty engine computer driver for the leak detection pump circuit, though this is less common.
Blown fuse or relay that supplies power to the leak detection pump, leading to a high-voltage signal on the control side.

How to diagnose and fix it

Use a scan tool to command the leak detection pump on and off while watching the control circuit voltage to confirm the fault is active.
Visually inspect the pump connector and the computer connector for corrosion, bent pins, or water intrusion, and clean or repair as needed.
Disconnect the pump and measure resistance across its control terminals; compare to the manufacturer's specification to rule out an open winding.
Check the control wire for continuity to ground and for short to battery voltage with a multimeter, repairing any damaged section of harness.
Verify that the pump receives proper power and ground at its connector when the key is on, and check any related fuse or relay.
If the circuit and pump test good, substitute a known-good pump or use a test light to confirm the computer can ground the circuit; replace the computer only if the driver is confirmed faulty.
Clear the code and perform a drive cycle to verify the repair and confirm the monitor runs without resetting the code.

Don't overlook the simple wiring checks

A high-voltage code on a control circuit often results from a disconnected or corroded connector rather than a failed pump, so always inspect the plug before condemning parts.
The leak detection pump may share a power feed with other emissions components, and a blown fuse can cause a high signal on the control wire even though the pump itself is fine.
Some vehicles set P2402 when the pump motor is electrically open, which can happen from normal wear, but the same code can appear if the computer's driver circuit fails, so test the driver before replacing the computer.
A short to voltage in the harness can be intermittent and only set the code when the engine is running or when the vehicle is driven over bumps, so wiggle-test the harness while monitoring live data.
This code does not always mean the pump needs replacement; a simple terminal tension issue at the connector can cause the same high-voltage reading.

Can I keep driving with P2402?

The vehicle is safe to drive under normal conditions because this fault affects only the emissions self-test and does not compromise engine performance or safety. Avoid towing heavy loads or driving in dusty environments until repaired, and address the code promptly to prevent a failed emissions inspection.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.