Short to voltage on the signal wire between the sensor and the computer; Contaminated or failed oxygen sensor internally shorted to its heater circuit; Chafed or damaged wiring harness rubbing against a hot or sharp component; Corroded or loose connector pins at the sensor or computer; Failed engine computer driver circuit for the sensor signal; Exhaust leak upstream of the sensor drawing in air and confusing the reading; Rich-running engine condition from a leaking injector or high fuel pressure that the sensor correctly reports

DTC codes / P01xx · Fuel and air metering / P0144

P0144O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)

Q: What does code P0144 mean?

O2 Sensor Circuit High Voltage (Bank 1 Sensor 3). P0144 means the engine computer detected a persistently high voltage on the downstream oxygen sensor circuit for Bank 1 Sensor 3, which is the post-catalytic converter sensor on that bank. A high voltage signal tells the computer the sensor is reporting a rich exhaust condition or that the signal wire is shorted to voltage, so the computer flags the circuit as out of range.

P0144 means the engine computer detected a persistently high voltage on the downstream oxygen sensor circuit for Bank 1 Sensor 3, which is the post-catalytic converter sensor on that bank. A high voltage signal tells the computer the sensor is reporting a rich exhaust condition or that the signal wire is shorted to voltage, so the computer flags the circuit as out of range.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
A slight decrease in fuel economy as the computer adjusts fuel trim based on a false rich signal
Rough idle or hesitation if the false rich reading skews the air-fuel mixture
Failed emissions test due to the oxygen sensor monitor not completing or reporting a fault
In rare cases, black smoke or a strong fuel smell from the tailpipe if the engine runs overly rich

Common causes, most likely first

Short to voltage on the signal wire between the sensor and the computer
Contaminated or failed oxygen sensor internally shorted to its heater circuit
Chafed or damaged wiring harness rubbing against a hot or sharp component
Corroded or loose connector pins at the sensor or computer
Failed engine computer driver circuit for the sensor signal
Exhaust leak upstream of the sensor drawing in air and confusing the reading
Rich-running engine condition from a leaking injector or high fuel pressure that the sensor correctly reports

How to diagnose and fix it

Scan all modules and record freeze-frame data to confirm the code and check for related oxygen sensor or fuel trim codes
Inspect the sensor wiring and connector for chafing, corrosion, or contact with the exhaust; repair as needed
Measure the sensor signal voltage with a digital multimeter and compare it to the manufacturer's specification
Check the sensor heater circuit resistance and supply voltage to rule out an internal sensor short
Perform a propane enrichment test or use a scan tool to watch the sensor voltage respond to a known rich condition
If the signal wire shows battery voltage with the sensor disconnected, trace the harness for a short to voltage and repair it
Replace the oxygen sensor only after confirming the circuit and fuel trims are otherwise normal, then clear codes and verify the monitor runs

Why a high voltage reading is not always the sensor

A short to voltage on the signal wire is the most common cause of P0144, and it often happens where the harness passes near the starter or alternator wiring.
Technicians frequently replace the downstream sensor only to find the code returns because the real fault is a chafed wire hidden behind the engine block.
A genuinely rich exhaust mixture from a leaking injector can drive the downstream sensor voltage high and set P0144 even though the sensor is working correctly.
On some vehicles, a failing upstream sensor can cause the computer to overcorrect fuel delivery and push the downstream sensor into a high-voltage range.
The downstream sensor on Bank 1 Sensor 3 is often located after a secondary catalytic converter on V6 and V8 engines, so exhaust leaks at the converter flange can mimic a sensor fault.

Can I keep driving with P0144?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration or towing because a false rich signal can cause the engine to run leaner than intended and overheat the catalytic converter. If the check engine light starts flashing or you notice rough running, stop driving and have it towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.