What it means
Same as P2494 on bank 2. 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
The Bank 2 EGR cooler bypass position sensor sends valve-position feedback to the control module. This code sets when the sensor signal falls below the plausible range, indicating a low-signal circuit condition rather than simply a disagreement between valve position and command.
Common causes
Most likely first.
- Signal shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 check Bank 2 bypass sensor live data to confirm the signal is low when the fault occurs.
- Inspect the Bank 2 sensor connector and harness for corrosion, chafing, crushed insulation, or a signal wire contacting ground.
- Check connector pin fit and corrosion, since added contact resistance can pull the sensor signal down.
- Test the signal wire for a short to ground and check its reference and ground circuits against the manufacturer's specification.
- If wiring and connector checks pass, test the Bank 2 sensor output against the manufacturer's specification before replacing it.
Common fixes
- Clean and secure corroded or loose Bank 2 sensor connector pins.
- Repair chafed Bank 2 harness insulation or a signal wire shorted to ground.
- Restore a faulty sensor reference or ground connection.
- Replace the Bank 2 bypass position sensor if its output remains too low with sound wiring.
Can I keep driving?
A short, gentle drive may be possible if the engine runs normally, but avoid heavy acceleration if it pings or hesitates. The fault can impair EGR control, raise NOx emissions, and cause an emissions test failure.
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.