OBD-II code · Powertrain (generic)
P046F EGR Sensor B Circuit Intermittent/Erratic
EGR sensor B signal jumps or drops out intermittently. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
Is it safe to drive with P046F?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIntermittent connector
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- Parts involved
- Egr Valve
Related codes
- P044EEGR Sensor C Circuit Intermittent/Erratic
- P046DEGR Sensor A Circuit Intermittent/Erratic
- P046CEGR Sensor A Circuit Range/Performance
- P046EEGR Sensor B Circuit Range/Performance
- P0470Exhaust Pressure Sensor A Circuit
- P0471Exhaust Pressure Sensor A Circuit Range/Performance
- P0472Exhaust Pressure Sensor A Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.