OBD Guide

B0509

Output Air Temperature Sensor 3 Circuit

B0509 is an OBD-II diagnostic trouble code meaning: Output Air Temperature Sensor 3 Circuit. Common causes: open or short circuit in wiring harness, air temperature sensor 3 malfunction. Estimated repair cost: $22–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–56 (est.)

Symptoms

  • Incorrect operation of the climate control system
  • Increased fuel consumption (if the sensor is connected to the intake)
  • Incorrect air temperature readings on the display

Causes

  • Open or short circuit in wiring harness
  • Air temperature sensor 3 malfunction
  • Poor contact in the sensor connector
  • Problems with the control unit

How to Fix

  1. Check the integrity of the wiring harness and sensor connector
  2. Measure the sensor resistance (compare with the norm)
  3. Check voltage and ground in the sensor circuit
  4. Replace sensor if necessary
  5. Reset the error and check if it returns

Related codes

Error B0509 by Vehicle Brand

FAQ

What does the B0509 code mean?

B0509 is an OBD-II diagnostic trouble code that indicates: Output Air Temperature Sensor 3 Circuit

What causes a B0509 error code?

The most common causes of B0509 include: Open or short circuit in wiring harness; Air temperature sensor 3 malfunction; Poor contact in the sensor connector; Problems with the control unit.

How do I fix a B0509 diagnostic trouble code?

To fix B0509: Check the integrity of the wiring harness and sensor connector. Measure the sensor resistance (compare with the norm). Check voltage and ground in the sensor circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B0509?

Limited driving only, diagnose soon

How much does it cost to fix B0509?

The estimated repair cost for B0509 is $22–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat