OBD-II Code
P0144
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$90–$620
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0144 means the bank 1, sensor 3 O2 sensor is reading stuck-high voltage — signal voltage above the upper threshold (typically over 1.0V for longer than 60-120 seconds, where a healthy narrow-band sensor maxes around 0.9V at full rich).
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0144 means the bank 1, sensor 3 O2 sensor is reading stuck-high voltage — signal voltage above the upper threshold (typically over 1.0V for longer t…
P0144 means the bank 1, sensor 3 O2 sensor is reading stuck-high voltage — signal voltage above the upper threshold (typically over 1.0V for longer than 60-120 seconds, where a healthy narrow-band sensor maxes around 0.9V at full rich). Stuck-high indicates either the sensor is shorted internally to its heater 12V supply, the signal wire is shorted to a positive reference somewhere in the harness, or the exhaust upstream of sensor 3 is running genuinely rich enough to consume every molecule of oxygen — which on a post-second-cat sensor is a very different problem than P0172 system-rich.
Cheapest-first ladder
- Scan live data and compare B1S3 voltage to B1S1 — if B1S1 is also pegged high (over 0.85V with no switching), the engine is genuinely flooded rich (leaking injector, ruptured fuel pressure regulator diaphragm bleeding fuel into the vacuum line, stuck-closed EVAP purge) and the sensor is reporting correctly.
- Unplug B1S3 with the engine running — voltage at the signal pin should drop to the ECM's 0.45V bias; if it stays pinned at 1.0V or higher with the sensor disconnected, the harness has a positive short between signal and the heater feed.
- Inspect the connector for melted plastic — sensor 3 lives close to the exhaust and a melted connector can fuse the signal pin to the heater pin internally.
- If wiring is good and B1S1 is normal, replace B1S3. The expensive misdiagnosis is condemning the fuel pressure regulator at $250-$450 when the real fault is a chafed wire in the rear underbody harness — easy to miss without a continuity sweep.
Vehicle-specific patterns2009-2014 Ford F-150 3.5L EcoBoost throws P0144 on bank 1 sensor 3 from a known leaking injector pattern on bank 1 (the rich cylinder dumps fuel thro…
- 2009-2014Ford F-150 3.5L EcoBoost throws P0144 on bank 1 sensor 3 from a known leaking injector pattern on bank 1 (the rich cylinder dumps fuel through the cat and pegs the rear sensor) — pull injector balance data before the sensor.
- 2005-2010Jeep Grand Cherokee/Commander 5.7L Hemi sees P0144 from a melted bank 1 sensor 3 connector where it routes too close to the rear cat heat shield.
- 2004-2008Mercedes-Benz ML500/ML550 with the M113/M273 V8 throws P0144 on bank 1 sensor 3 from an internal short in the OEM Bosch sensor after roughly 80-110k miles — a documented Mercedes pattern.
- 2008-2013BMW E70 X5 4.8i / N63 X5 5.0i sees P0144 on bank 1 sensor 3 from the well-known fuel-injector index-code mismatch (injectors swapped without recoding) running cylinders 1-4 rich enough to peg the rear sensor.
Estimated repair$90 to $620.
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