P2403: EVAP System Leak Detection Pump Sense Circuit/Open

What it means

The control module detects an open or interrupted sense circuit for the EVAP leak detection pump, so it may not receive the expected pump feedback.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The leak detection pump has a sense circuit that reports feedback to the control module while the EVAP system runs its leak check. This code sets when that feedback circuit is open or interrupted, leaving the module without the expected pump signal.

Common causes

Most likely first.

1. Open in pump or sense wiring
2. Pin pushed back out of connector body
3. Cracked solder joint inside the module or sensor

Symptoms

• Check engine light on

How to diagnose it

1. Record freeze-frame data and see whether the code appears during an EVAP test when pump feedback should be present.
2. Inspect the leak detection pump sense-wire harness and connector for breaks, corrosion, loose terminals, or a pin pushed back into the connector.
3. Check sense-circuit continuity from the pump connector toward the control module using the manufacturer's wiring information.
4. Check the relevant connector terminals for secure contact and inspect accessible module or sensor connections for damage.
5. If the wiring and terminals pass, test the pump's sense output and the receiving module circuit against the manufacturer's specification.

Common fixes

• Reseat a pushed-back terminal and secure the sense-circuit connector.
• Clean corrosion or repair a loose terminal in the pump sense circuit.
• Repair an open or broken sense wire.
• Repair or replace the pump or module only if testing confirms the source of the missing feedback.

Can I keep driving?

The open sense circuit usually does not affect engine operation, so driving is generally possible. The module may be unable to verify the leak test, which can increase emissions and prevent an emissions inspection from passing.