What it means
Exhaust Gas Temperature Sensor Circuit High Bank 2 Sensor 1: the signal voltage is above the expected range. The ECU uses this temperature to protect the catalyst and diesel particulate filter.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 2 Sensor 1 measures exhaust gas temperature at the first monitored position on the Bank 2 exhaust side. P0549 sets when the sensor signal rises above the expected range, which can happen if the signal is shorted to a supply or a poor connector contact drives it high.
Common causes
Most likely first.
- Signal shorted to supply
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light on
- Possible reduced engine power or altered exhaust-system operation
How to diagnose it
- Record freeze-frame data and check whether Bank 2 Sensor 1 live temperature is implausibly high or fixed.
- With the exhaust cool, inspect the Bank 2 Sensor 1 harness for pinched insulation or contact with a battery supply wire.
- Check the connector terminals for corrosion, looseness, or damage that could create a high signal.
- Use the wiring diagram to test the signal circuit for a short to supply and check the sensor against the manufacturer's procedure.
- After repair, clear the code and confirm that Bank 2 Sensor 1 data changes plausibly as the exhaust warms.
Common fixes
- Repair pinched or damaged Bank 2 Sensor 1 wiring that is shorted to a supply.
- Clean or repair corroded or loose connector terminals.
- Replace the Bank 2 Sensor 1 exhaust temperature sensor if it fails testing.
- Repair a faulty circuit connection identified during diagnosis.
Can I keep driving?
If the vehicle shows reduced power or changed exhaust-system operation, keep driving to a minimum and avoid heavy loads or sustained high speeds. A signal stuck high can make Bank 2 exhaust temperature protection or aftertreatment control unreliable.
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.