P2401Generic code

P2401 Code: Evaporative Emission System Leak Detection Pump Control Circuit Low

The P2401 code means the computer sees low voltage in the control circuit of the EVAP leak detection pump, either a short to ground or a missing supply. The system cannot check for fuel vapor leaks and the EVAP monitor does not complete. It does not affect how the car drives, but it can keep you from passing an emissions inspection.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$60 to $400
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Common in: Dodge, Jeep

Updated Reviewed by Renzo Chacca

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What the P2401 code means

On many vehicles the EVAP system is tested with a small pump (an LDP or an ELCM) that pressurizes the tank and hoses or pulls a vacuum on them with the engine off or idling. By measuring how long it takes to reach pressure and how long the pressure holds, the computer can detect leaks as small as half a millimeter (about 0.02 inch).

The computer monitors the control circuit from its own driver transistor. The P2401 code means low voltage in the control circuit (a short to ground or a missing supply). Before you replace the component, check the fuse, relay, connector and wiring, because they are the most common cause.

The pump usually sits next to the canister, near the fuel tank, where it is exposed to road water and dirt.

To confirm it, unplug the component with the key on and watch what happens to the reading or the code. If the value jumps to the opposite extreme, the wiring is fine and the component is the one pulling the signal to ground. If nothing changes, look for the short in the wire, starting where the harness rubs against the engine, the chassis or the exhaust.

P2401 code symptoms

  • Check engine light or another warning light on.
  • The system cannot check for fuel vapor leaks and the EVAP monitor does not complete.

Likely causes of the P2401 code

  1. Control wire shorted to ground. The component can stay on all the time, or the computer cuts the command to protect itself.
  2. Interrupted supply. A blown fuse, a faulty relay or a cut wire.
  3. Shorted component. Resistance far below the specification.
  4. Connector with moisture that creates a path to ground.

How to diagnose the P2401 code step by step

  1. Activate the component with the scan tool and check whether it responds.
  2. Check the fuse and relay. Measure the voltage on both sides of the fuse, and swap the relay with an identical one.
  3. Measure the supply at the connector. Battery voltage with the key on or when it is activated.
  4. Measure the resistance of the component and compare it with the manual. Check the insulation to ground too.
  5. Check the control wire. Continuity to the computer and no shorts.

How to fix the P2401 code

  • Repair the connector, the wiring or the supply.
  • Replace the EVAP leak detection pump if it does not respond with correct power and command.
  • Clear the codes and verify.

After the repair, run the EVAP monitor and make sure the P2401 code stays away. The monitor can take a few drive cycles to complete.

Technical reference data

  • 12 V supply from a relay or from the computer.
  • Many pumps include a switching valve and a pressure sensor.
  • These are reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

This code is common on makes that use a leak detection pump or a leak detection module near the canister.

P2401 on Chrysler

Frequent on Chrysler vehicles, which use an LDP pump.

P2401 on Dodge

Frequent on Dodge vehicles, which use an LDP pump.

P2401 on Jeep

Frequent on Jeep vehicles, which use an LDP pump.

P2401 on Volkswagen

Frequent on Volkswagen vehicles.

P2401 on Audi

Frequent on Audi vehicles.

P2401 on Toyota

Frequent on Toyota vehicles with a leak detection module built into the canister.

Frequently asked questions about P2401

Can I drive with a P2401 code?
Yes. It does not affect how the vehicle drives, but it can keep you from passing an emissions inspection.
What does the EVAP leak detection pump do?
On many vehicles the EVAP system is tested with a small pump (an LDP or an ELCM) that pressurizes the tank and hoses or pulls a vacuum on them. By measuring how long it takes to reach pressure and how long it holds, the computer can detect leaks as small as half a millimeter.
Does the part always have to be replaced?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P2401?
Roughly $60 to $400. A connector or fuse is at the low end, and a new pump with labor is closer to the top.
What does the P2401 code mean?
It is a generic OBD2 code that means the control circuit of the EVAP leak detection pump has low voltage. The cause is a short to ground or a missing supply.
Will a P2401 code clear itself?
If the cause was moisture in the connector, the light may go out once it dries. A shorted pump or a damaged wire will bring the code back, so find the cause.
What is the most common cause of P2401?
A fault in the fuse, relay, connector or wiring is the most common, ahead of the pump itself. A control wire shorted to ground is a close second.

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Questions about the P2401 code

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