What it means
EGR sensor B reads in range but plausibility check fails — slow response or stuck reading. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
EGR sensor B reports a position or operating signal that the control module uses to check EGR flow response. This code sets when the signal stays within its electrical range but responds too slowly or implausibly as the EGR system changes state.
Common causes
Most likely first.
- Sensor drift
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
How to diagnose it
- Record freeze-frame data and compare EGR sensor B live data with commanded EGR operation to see when its response becomes implausible.
- With the engine off, inspect sensor B's mounting and connector for looseness, contamination, corrosion, or damage that could damp the signal.
- Check the EGR sensor B wiring for chafing, heat damage, poor routing, and loose terminals.
- Command the EGR system through an appropriate scan-tool test, if supported, and watch whether sensor B changes smoothly and promptly.
- Test sensor B's supply, ground, and signal circuit against the wiring diagram and manufacturer's specification.
- If wiring and mounting are sound but sensor B still responds slowly or inaccurately, test or replace the sensor as directed by vehicle service information.
Common fixes
- Secure sensor B and its mounting so it cannot move or damp the signal.
- Clean and reconnect the sensor B connector; repair loose or corroded terminals.
- Repair damaged wiring or poor sensor grounds.
- Replace EGR sensor B if its response remains slow or implausible after circuit checks.
Can I keep driving?
You can usually drive gently for a short time if the engine runs smoothly, but avoid heavy acceleration and sustained high loads because poor EGR response can contribute to knocking and excess NOx emissions. Stop if rough running or power loss becomes severe.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.