DTC (Diagnostic Trouble Code) P014400.
In most OEM formats, P0144 or P0144-00 corresponds to:

✅ P0144 – O2 Sensor Circuit High Voltage (Bank 1, Sensor 3)

What it means

The engine control module detects higher-than-normal voltage from the oxygen sensor located after the catalytic converter on Bank 1.

This sensor measures oxygen content in the exhaust to monitor catalytic converter efficiency. High voltage usually means the sensor is reading too rich (too much fuel / too little oxygen) or there’s a circuit fault.

🔧 Common Causes

1. Faulty O2 sensor (Bank 1, Sensor 3)

2. Short to voltage in the O2 sensor signal wire

3. Damaged wiring harness / poor ground

4. Exhaust leaks before the sensor

5. Rich-running condition (less common for post-cat sensor)

6. Contaminated sensor (oil, coolant, silicone)

7. Faulty ECU (rare)

🛠️ Diagnostic Steps for a Technician / Workshop

* Scan Live Data

Check B1S3 voltage: typically should cycle around 0.1–0.9V, but slower and more stable than front sensors.

If fixed high (~0.9–1.0V), suspect short or rich condition.

* Inspect Wiring

Look for melted wires near exhaust.

Check for short-to-voltage or high resistance on sensor signal wire.

* Check Sensor Heater Circuit

A failing heater can skew sensor readings.

Test resistance of the heater element vs OEM spec.

* Exhaust Leak Check

Ensure no leak between catalytic converter and B1S3 location.

* Fuel Trim Review

If long-term trim is highly negative, the engine may be running rich.

🔧 Common Fixes

Replace O2 sensor (most common fix)

Repair wiring harness or connectors

Fix exhaust leaks

Address engine running rich (if applicable)

Clear code and test drive

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