OBD-II code · Powertrain (generic)
P0409 Exhaust Gas Recirculation Sensor "B" Circuit High
Exhaust Gas Recirculation Sensor "B" Circuit High: the signal voltage is above the expected range. Without valid EGR feedback the ECU disables exhaust gas recirculation and may set further EGR codes.
Is it safe to drive with P0409?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor circuit shorted to supply
- PossibleEGR position sensor B failed
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Egr Position Sensor, Egr Sensor Wiring
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.