P2402Generic code

P2402 Code: Evaporative Emission System Leak Detection Pump Control Circuit High

The P2402 code means the computer sees high voltage in the control circuit of the EVAP leak detection pump, either an open circuit or a short to voltage. 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

Updated Reviewed by Renzo Chacca

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What the P2402 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 P2402 code means high voltage in the control circuit (an open circuit or a short to voltage). 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, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be less than 1 ohm, and an infinite reading means the wire is open. If the wiring is good, measure the component itself: infinite resistance confirms it is open inside.

P2402 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 P2402 code

  1. Loose or broken connector. The most common cause, especially after another repair.
  2. Coil or motor open with infinite resistance.
  3. Control wire cut between the component and the computer.
  4. Short to 12 V. The control wire touches another wire that carries voltage.

How to diagnose the P2402 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 P2402 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 P2402 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.

P2402 on Chrysler

Frequent on Chrysler vehicles, which use an LDP pump.

P2402 on Dodge

Frequent on Dodge vehicles, which use an LDP pump.

P2402 on Jeep

Frequent on Jeep vehicles, which use an LDP pump.

P2402 on Volkswagen

Frequent on Volkswagen vehicles.

P2402 on Audi

Frequent on Audi vehicles.

P2402 on Toyota

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

Frequently asked questions about P2402

Can I drive with a P2402 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 P2402?
Roughly $60 to $400. A connector or wire repair is at the low end, and a new pump with labor is closer to the top.
What does the P2402 code mean?
It is a generic OBD2 code that means the control circuit of the EVAP leak detection pump has high voltage. The cause is an open circuit or a short to voltage.
Will a P2402 code clear itself?
If a connector was only loose for a moment, the light may go out after several drive cycles. An open pump or a cut wire will bring the code back, so find the cause.
What is the most common cause of P2402?
A loose or broken connector, especially after another repair. An open pump coil and a cut control wire come next.

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