P2408

Fuel Cap Sensor/Switch Circuit

Evaporative emissions (EVAP) Generic OBD-II Low

What it means

P2408 sets when the engine computer sees an electrical fault in the fuel cap sensor or switch circuit, which is part of the evaporative emissions system. It does not affect how the vehicle runs. The usual causes are wiring or connector problems, a failed sensor, or a cap that is not fully closed on systems that detect cap position.

Low

Can I keep driving? Safe to drive. This is an emissions/sensor fault with no effect on how the vehicle runs, but it may fail an emissions test.

Real-world scan data

Seen in

984

scans in the past year

Found in

0.2%

of scans

0.3%

of scans that found faults

Appears alongside · share of P2408 scans

U0100in 14.7% of scans

P0607in 14.1% of scans

P0300in 11.3% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
No noticeable change in how the vehicle drives
May fail an emissions/readiness test

Common causes

Most likely first

Corroded or loose connector at the fuel cap sensor/switchLikely
Open or shorted wiring in the sensor/switch circuitCommon
Failed fuel cap sensor or switchCommon
Fuel cap not fully closed or seated (on systems that sense cap position)Less often
Failed PCM/ECM (rare)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data, then confirm the fuel cap is the correct type and fully closed.
Inspect the fuel cap sensor/switch connector and wiring for corrosion, opens, and shorts.
Test the sensor/switch signal against spec with a scan tool.
Replace the fuel cap sensor/switch if it fails testing.
Clear the code and complete a drive cycle to confirm the repair.

FAQ

Quick answers

Is it safe to drive with P2408?+

Yes. It does not affect drivability or safety. It is an emissions-related fault, so repair it before an emissions test and to clear the check-engine light.

Can I just clear P2408?+

You can, but it returns unless the cap position, wiring, or sensor is corrected.

Read & clear P2408 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX