EVAP Leak Detection Pump Sense Circuit High
The P2406 code indicates that the Engine Control Module (ECM) has detected a voltage signal from the evaporative emission (EVAP) leak detection pump sense circuit that is higher than the expected range. This circuit monitors the pump's operation during the EVAP system leak test. A high voltage reading typically points to a short to power, a faulty pump, or wiring issues. The EVAP system prevents fuel vapors from escaping into the atmosphere, so this code can affect emissions and may trigger the Check Engine Light.
01. Most Common Causes
- Faulty EVAP leak detection pump
- Short to voltage in the sense circuit wiring
- Corroded or damaged connector at the pump
- Failed ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Possible fuel odor
- No noticeable drivability issues
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve freeze frame data and verify the code.
Step 2: Visually inspect the EVAP leak detection pump and its wiring for damage, corrosion, or loose connections.
Step 3: Disconnect the pump connector and measure voltage at the sense circuit (should be 0V with key on, engine off). If voltage is present, repair short to power.
Step 4: Test the pump resistance and operation per manufacturer specifications; replace if out of range.
Step 5: Clear the code and perform a drive cycle to confirm repair.
04. Commonly Affected Makes
05. 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 you may fail an emissions test. It is recommended to diagnose and repair promptly to avoid potential fuel vapor leaks.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on whether the pump needs replacement (part cost $30-$80) and labor rates.