P2404Generic code

P2404 Code: Evaporative Emission System Leak Detection Pump Sense Circuit Range/Performance

The P2404 code means the sensor of the EVAP leak detection pump is giving a reading that makes electrical sense but does not match what the computer expects. The main effect is that the EVAP monitor does not complete. It does not affect how the car drives.

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 P2404 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 sensor works as a switch: the computer sees a high or a low voltage depending on its position. A range or performance fault means the sensor is measuring, but measuring wrong, or that there is a real abnormal condition. That is what the P2404 code reports.

The computer reads a switch or a pressure sensor inside the pump to learn whether it reached the test pressure.

This kind of fault is usually not solved with a multimeter alone, because electrically everything looks fine. You have to compare what the part says with reality: use a gauge, a thermometer, a tachometer, or command the component with the scan tool and see whether the physical result matches the order.

P2404 code symptoms

  • Check engine light on.
  • The EVAP monitor does not complete.

Likely causes of the P2404 code

  1. Aged or out-of-calibration sensor. It gives believable readings that are wrong.
  2. Real abnormal condition. The system is genuinely operating outside normal.
  3. High resistance in the connector from corrosion, which shifts the reading.
  4. Damaged or blocked port, hose or tone wheel, depending on the type of sensor.

How to diagnose the P2404 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check power and ground with the key on: correct reference voltage and less than 0.1 V drop on the ground.
  4. Measure the signal with the connector plugged in and see whether it changes with the conditions.
  5. Do a wiggle test on the wiring with the scan tool in graph mode.
  6. Check the continuity of each wire to the computer (less than 1 ohm).

How to fix the P2404 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one.
  • Clear the codes and verify with a road test.

After the repair, run the EVAP monitor and make sure the P2404 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.

P2404 on Chrysler

Frequent on Chrysler vehicles, which use an LDP pump.

P2404 on Dodge

Frequent on Dodge vehicles, which use an LDP pump.

P2404 on Jeep

Frequent on Jeep vehicles, which use an LDP pump.

P2404 on Volkswagen

Frequent on Volkswagen vehicles.

P2404 on Audi

Frequent on Audi vehicles.

P2404 on Toyota

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

Frequently asked questions about P2404

Can I drive with a P2404 code?
Yes. It does not affect how the vehicle drives, but the EVAP monitor will not complete until it is repaired.
Does the sensor have to be replaced?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor.
What does the EVAP leak pump sensor 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. A switch or pressure sensor inside the pump tells the computer whether the test pressure was reached, which is how it detects leaks as small as half a millimeter.
How much does it cost to fix P2404?
Roughly $60 to $400. A connector repair is at the low end, and a new pump with labor is closer to the top.
What does the P2404 code mean?
It is a generic OBD2 code for a range or performance fault in the circuit of the EVAP leak detection pump sensor. The sensor reads, but what it reads does not match what the computer expects.
Will a P2404 code clear itself?
If the odd reading was a one-time event, the light can go out after several drive cycles. A drifting sensor or a corroded connector will bring it back, so find the cause.
What is the most common cause of P2404?
An aged sensor that drifted out of calibration, or a connector with corrosion that adds resistance. Both give believable but wrong readings.

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