Faulty exhaust gas temperature sensor (internal failure or contamination); Damaged, chafed or heat-affected wiring to the sensor; Corroded, loose or contaminated connector terminals; Exhaust leak near the sensor causing false readings; Open circuit or short in the sensor supply or reference voltage or ground circuit; Faulty engine control unit.

P0544

Exhaust Gas Temperature Sensor Circuit Bank 1 Sensor 1.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
5: AreaVehicle speed, idle control and auxiliary inputs
44: FaultThe specific fault in that area

What it means

P0544 is the generic code for a fault in the Bank 1 Sensor 1 exhaust gas temperature sensor circuit, normally the sensor sited upstream of the catalyst or turbocharger. The engine control unit has detected a signal that is out of range, shorted, open circuit or otherwise implausible compared with its expected values or the other temperature sensors.

Symptoms

Engine management light on
Reduced power or the engine going into limp mode on some vehicles
Diesel particulate filter regeneration not completing, or a DPF warning light
Increased fuel consumption
Other exhaust temperature or catalyst codes stored alongside

Possible causes

Faulty exhaust gas temperature sensor (internal failure or contamination)likely
Damaged, chafed or heat-affected wiring to the sensorlikely
Corroded, loose or contaminated connector terminalslikely
Exhaust leak near the sensor causing false readingspossible
Open circuit or short in the sensor supply or reference voltage or ground circuitpossible
Faulty engine control unitrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, checking for other exhaust temperature, particulate filter or catalyst codes.
Check for any manufacturer bulletins or known issues for the specific model and engine, as sensor position and type vary.
Visually inspect the sensor, its wiring and the connector for heat damage, chafing, corrosion, water ingress or oil contamination.
Inspect the exhaust around the sensor for leaks, and check the sensor is correctly fitted and tight.
With the engine cold, compare the live data from the Bank 1 Sensor 1 reading with ambient or other temperature sensors, as they should be similar.
Check the live reading changes sensibly as the engine warms up, and compare it with the other exhaust temperature sensors.
Test the wiring for continuity, short to ground, short to supply and the reference voltage and ground at the connector, using the wiring diagram for the vehicle.
Test the sensor resistance against the manufacturer's specification at a known temperature, if the specification is available.

How to fix

Replace the exhaust gas temperature sensor if it is faulty or out of specification.
Repair or replace damaged wiring and fit new connector terminals or the connector as needed.
Clean and secure the connector, and apply the correct sealing where the design allows.
Repair exhaust leaks near the sensor.
Replace the engine control unit only after all wiring and sensor faults have been ruled out and the fault is confirmed by the manufacturer's procedure.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but the engine control unit may be unable to protect the turbocharger, catalyst or particulate filter without a valid reading, so get it checked soon. If the car goes into limp mode, or there is a strong smell or a flashing warning light, limit driving.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.