P2403 - EVAP Leak Detection Pump Sense Circuit/Open
The P2403 code indicates an open or malfunction in the sense circuit of the Evaporative Emission (EVAP) system leak detection pump. This pump is part of the EVAP system's diagnostic module, which pressurizes the system to check for leaks. An open circuit means the PCM detects no voltage or signal from the pump's sense circuit, often due to wiring issues, a faulty pump, or a blown fuse. This can prevent the system from performing leak tests and may trigger the check engine light.
1. Most Common Causes
- Open circuit, short to ground, or short to voltage in the EVAP leak detection pump sense circuit
- Damaged, corroded, or disconnected connector at the leak detection pump or PCM
- Internally failed leak detection pump (LDP) causing no sense signal
- Excessive resistance in the harness due to bent pins, corrosion, or poor splices
- Faulty PCM/ECM (rare cause)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed EVAP system leak test during emissions inspection
- Possible fuel odor (rare)
- No noticeable drivability issues
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P2403 and check for related EVAP codes.
Step 2: Visually inspect the leak detection pump connector and wiring for damage, corrosion, or loose connections.
Step 3: Test the pump's sense circuit for continuity and voltage using a multimeter; compare to manufacturer specs.
Step 4: Check the EVAP system fuse and relay; replace if blown.
Step 5: If wiring and power are good, replace the leak detection pump assembly.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but the check engine light will be on and the vehicle may fail an emissions test. The EVAP system prevents fuel vapors from escaping, so a leak could increase emissions, but drivability is usually unaffected.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the cause. If the pump needs replacement, parts cost $30-$80 and labor $50-$100.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.