P2406
EVAP System Leak Detection Pump Sense Circuit High
Evaporative emissions (EVAP)
Generic OBD-II
Low
What it means
P2406 means the ECM has seen high voltage on the sense circuit of the EVAP leak detection pump — the device that pressurizes the fuel-vapor system to check for leaks. It's an electrical circuit fault, not a fuel leak, and it doesn't affect drivability. The usual causes are a failed leak detection pump or a wiring/connector problem in its sense circuit.
Low
Can I keep driving? Safe to drive — this is an emissions self-test circuit fault with no effect on how the car runs; it just needs fixing to pass an emissions test.
Common symptoms
What you'll notice
- Check-engine light on
- No change in how the car drives
- May fail an emissions/readiness test
- Possible faint fuel smell only if an actual EVAP leak also exists
Common causes
Most likely first
- Failed EVAP leak detection pump (LDP)Likely
- Open or short-to-voltage in the LDP sense circuit wiringCommon
- Corroded or loose LDP connectorCommon
- Poor ground on the LDP circuitLess often
- Faulty ECM driver (less common)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for other EVAP or LDP codes.
- Inspect the leak detection pump connector and wiring for damage, corrosion, or a loose pin.
- Check the sense-circuit wiring for an open or short to voltage back to the ECM.
- Verify the LDP's ground and supply.
- If wiring and grounds are good, replace the leak detection pump. Clear and re-test after a drive cycle.
FAQ
Quick answers
Is it safe to drive with P2406?+
Yes. This code is about the EVAP system's leak-detection self-test, not engine operation, so the car drives normally. Fix it to clear the light and pass emissions.
Can I just clear P2406?+
You can, but it returns once the EVAP monitor runs again unless the leak detection pump or its wiring is repaired.
Related codes
Often seen with P2406
Read & clear P2406 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX