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OBD-II Code

P0073

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)

$15–$350

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

$15 (sensor swap DIY) to $350 (sensor + harness repair + connector + labor at shop).

P0073 is the specific ambient air temperature sensor circuit HIGH INPUT fault — the inverse of P0072.

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.

  1. 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.

  2. 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.

  3. 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.

  4. 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 procedureP0073 is the specific ambient air temperature sensor circuit HIGH INPUT fault — the inverse of P0072.

P0073 is the specific ambient air temperature sensor circuit HIGH INPUT fault — the inverse of P0072. The PCM is seeing AAT signal voltage pinned at or above the high-voltage threshold (typically above 4.5-4.9V, which scales to a temperature reading at or above the 248 F ceiling of the sensor table), which physically means either the signal wire is open (broken between sensor and PCM), the sensor connector is disconnected, the sensor itself has failed open internally, or the signal wire is shorted to the 5V reference.

Cheapest-first ladder

  1. Scan live data and confirm AAT is pegged at the 248 F ceiling — that confirms a hard-open circuit, not a drift fault.
  2. Locate the sensor (bumper, mirror, behind grille per vehicle) and confirm it's still physically attached and connected — disconnected sensors from car-wash strikes or amateur bumper-cover R&R are #1 cause.
  3. With sensor unplugged, jumper the two pins of the connector together; if AAT now reads the 248 F ceiling AND the high-input code stays, the harness signal wire is open between connector and PCM; if AAT now flips to the -40 F floor, the harness is fine and the sensor was open internally.
  4. Ohm-out the sensor against the OEM thermistor table (typically 9-12 k-ohm at 32 F, 2-3 k-ohm at 70 F) — infinite resistance confirms a dead sensor.
  5. Swap the sensor ($15-50) and clear. The expensive misdiagnosis: don't condemn the PCM or the instrument cluster (which displays AAT) before doing the connector-jumper test — a broken connector latch that lets the sensor fall partway out is invisible from above and sets P0073 even though the sensor itself is fine.
Vehicle-specific patterns2009-2014 Ford F-150 and 2008-2016 Ford SuperDuty set P0073 most commonly from a sensor that's been knocked loose by a winter bumper strike or by car…
  • 2009-2014Ford F-150 and 2008-2016 Ford SuperDuty set P0073 most commonly from a sensor that's been knocked loose by a winter bumper strike or by car-wash brushes catching the harness — the connector backs out of the sensor body and reads open.
  • 2007-2014GM full-size trucks (Silverado, Sierra, Tahoe, Yukon) set P0073 from the bumper-mounted sensor harness being cut during off-road use or by tow-strap routing.
  • 2008-2015Dodge Ram and 2011-2018 Jeep Grand Cherokee/Dodge Durango set P0073 from grille-area harness fatigue at the grommet pass-through.
  • 2007-2013Mercedes-Benz GL/ML/R-Class mounts the AAT in the front bumper behind the lower grille and sets P0073 frequently after front-bumper R&R where the harness gets pinched or left disconnected.

Estimated repair$15 (sensor swap DIY) to $350 (sensor + harness repair + connector + labor at shop).

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