OBD-II Code
P0044
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)
$60–$380
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0044 is the 'circuit high' version of the bank-1 sensor-3 heater fault - the heater control signal is stuck above the upper electrical threshold or showing implausible current flow indicating a short-to-power.
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 procedureP0044 is the 'circuit high' version of the bank-1 sensor-3 heater fault - the heater control signal is stuck above the upper electrical threshold or…
P0044 is the 'circuit high' version of the bank-1 sensor-3 heater fault - the heater control signal is stuck above the upper electrical threshold or showing implausible current flow indicating a short-to-power. Diagnostic logic mirrors P0043 but inverted: instead of looking for shorts-to-ground or open circuits, look for shorts-to-battery or shorts to a 12V circuit anywhere in the harness between PCM and sensor.
Cheapest-first ladder
- Unplug the sensor and DMM the heater control pin to ground - a stuck-high reading with the sensor disconnected confirms harness short to power; a floating or zero reading means the sensor itself is the failure.
- Inspect the harness route under the vehicle for chafing against frame rails, body brackets, or against the exhaust pipe itself.
- Check sensor heater coil resistance - a partially shorted internal coil can pull excessive current and read as a short-to-power fault. The 20-minute DMM sequence catches harness-vs-sensor cleanly.
Vehicle-specific patterns2007-2014 Toyota Tundra / Sequoia 5.7L throws P0044 from chafed underbody harness at the body-mount near the bank-1 third O2 sensor.
- 2007-2014Toyota Tundra / Sequoia 5.7L throws P0044 from chafed underbody harness at the body-mount near the bank-1 third O2 sensor.
- 2008-2014Lexus GX460 / LX570 with the 5.7L throws P0044 from a known harness retainer issue that lets the wire rub against the frame.
- 2010-2016Toyota Sienna with the 2GR-FE throws P0044 from melted insulation when the underbody heat shield falls off.
- 2011-2018Lexus IS350 / GS350 with the 2GR-FSE throws P0044 from a failed heater coil internally on the rearmost sensor.
Estimated repair$60 to $380
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