What it means
The control module detects an electrical fault in the exhaust gas temperature sensor circuit at Bank 1 Sensor 1. Sensor location and its role in exhaust protection or aftertreatment vary by vehicle.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Bank 1 Sensor 1 is an exhaust gas temperature sensor at the first monitored position on the engine's Bank 1 exhaust side; its exact location and role vary by vehicle. The control module monitors the sensor circuit and sets P0544 when it detects an electrical fault, without specifying whether the signal is low or high.
Common causes
Most likely first.
- Exhaust gas temperature sensor failure
- Open or short in sensor wiring
- Loose, damaged, or corroded connector
Symptoms
- Check-engine light on
- Possible reduced engine power or altered exhaust-system operation
How to diagnose it
- Record freeze-frame data and compare Bank 1 Sensor 1 temperature readings with other exhaust temperature readings, if available.
- With the exhaust cool, inspect the Bank 1 Sensor 1 connector and nearby wiring for corrosion, loose pins, heat damage, or chafing.
- Check the sensor harness routing and connectors for an open or short, using the vehicle wiring diagram.
- Test the Bank 1 Sensor 1 circuit and sensor against the manufacturer's procedure to distinguish a sensor fault from a wiring fault.
- After repairs, clear the code and confirm that the sensor reading changes plausibly as the exhaust warms.
Common fixes
- Reconnect or clean the Bank 1 Sensor 1 connector if it is loose or corroded.
- Repair damaged or chafed wiring in the Bank 1 Sensor 1 circuit.
- Replace the Bank 1 Sensor 1 exhaust temperature sensor if circuit tests show it has failed.
- Repair a failed connector terminal or circuit connection identified during testing.
Can I keep driving?
If the vehicle has reduced power or altered exhaust-system operation, keep driving to a minimum and avoid heavy loads or sustained high speeds. An inaccurate temperature signal can interfere with exhaust protection or aftertreatment control.
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.