OBD Guide
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B2459

Auxiliary Heater Overheat Sensor Circuit Open

B2459 is an OBD-II diagnostic trouble code meaning: Auxiliary Heater Overheat Sensor Circuit Open. Common causes: broken wires in the harness, overheat sensor malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Auxiliary heater does not turn on
  • Incorrect heater operation
  • The malfunction indicator on the instrument panel lights up

Causes

  • Broken wires in the harness
  • Overheat sensor malfunction
  • Poor contact in connectors
  • Malfunction of the additional heater control unit

How to Fix

  1. Check the integrity of the wiring harness
  2. Check sensor connections and connectors
  3. Check the resistance of the overheating sensor
  4. Replace sensor if necessary
  5. Check the operation of the control unit

Related codes

B2458B2460B2461

FAQ

What does the B2459 code mean?

B2459 is an OBD-II diagnostic trouble code that indicates: Auxiliary Heater Overheat Sensor Circuit Open

What causes a B2459 error code?

The most common causes of B2459 include: Broken wires in the harness; Overheat sensor malfunction; Poor contact in connectors; Malfunction of the additional heater control unit.

How do I fix a B2459 diagnostic trouble code?

To fix B2459: Check the integrity of the wiring harness. Check sensor connections and connectors. Check the resistance of the overheating sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2459?

Limited driving only, diagnose soon

How much does it cost to fix B2459?

The estimated repair cost for B2459 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat