Short to voltage in the sensor signal wire, or chafed wiring touching a power feed; Faulty or contaminated Bank 1 Sensor 3 oxygen sensor; Damaged, corroded or loose connector or terminals at the sensor or its harness plug; Wiring damaged by heat or exhaust contact near the sensor; Open circuit or poor sensor ground causing a false high reading; Fault within the engine control unit.

P0144

O2 Sensor Circuit High Voltage Bank 1 Sensor 3.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
44: FaultThe specific fault in that area

What it means

P0144 is the generic code for a high voltage condition in the oxygen sensor circuit on Bank 1, Sensor 3. This sensor sits downstream of the catalytic converter, further along the exhaust than the usual post-cat sensor, and is only fitted on some vehicles. The control unit set the code because the signal voltage stayed higher than expected, typically stuck near the top of the sensor's range, for longer than the monitoring strategy allows.

Symptoms

Engine management warning light on
Usually no noticeable change in driveability
Possible slight change in fuel economy if other faults are present
Failed emissions test or readiness monitors not completing
Other oxygen sensor or fuelling codes stored alongside it

Possible causes

Short to voltage in the sensor signal wire, or chafed wiring touching a power feedlikely
Faulty or contaminated Bank 1 Sensor 3 oxygen sensorlikely
Damaged, corroded or loose connector or terminals at the sensor or its harness plugpossible
Wiring damaged by heat or exhaust contact near the sensorpossible
Open circuit or poor sensor ground causing a false high readingpossible
Fault within the engine control unitrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine temperature and load when the fault set.
Confirm which sensor is Bank 1 Sensor 3 on this model, as the layout and bank numbering vary by engine and exhaust design.
Visually inspect the sensor, wiring and connector for heat damage, chafing, corrosion, water ingress and security of routing.
Check for other oxygen sensor, misfire or fuel trim codes, and fix any related faults first.
With the ignition on and the sensor unplugged, measure the reference and signal voltages at the harness against the manufacturer's specification.
Check the signal and ground wires for continuity and for shorts to voltage or to each other.
View live sensor data after warming the engine and see whether the voltage is stuck high or responds to changes in mixture, comparing against model-specific values.
Check the sensor heater circuit and the engine control unit supply and grounds if the readings are inconsistent.

How to fix

Repair or replace damaged wiring, and secure it clear of hot or moving parts.
Clean or replace a corroded or damaged connector and terminals.
Replace the Bank 1 Sensor 3 oxygen sensor if it is faulty or contaminated, and find the cause of any contamination.
Restore a poor sensor ground or supply connection.
Repair any related fuelling or exhaust fault found, then clear the codes and confirm the monitors complete.

Can I keep driving?

Low severity

The car can normally be driven while you book it in, as this fault rarely affects safety or causes immediate damage. Do not leave it for long, as it may hide other faults and could lead to an emissions test failure.

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