OBD Guide
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B1858

Climate Control A/C Pressure Switch Circuit Failure

B1858 is an OBD-II diagnostic trouble code meaning: Climate Control A/C Pressure Switch Circuit Failure. Common causes: open or short circuit in wiring harness, air conditioner pressure sensor malfunction. Estimated repair cost: $56–167.

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

Symptoms

  • Air conditioner doesn't work
  • Check Engine Light Is On
  • Reduced cooling efficiency

Causes

  • Open or short circuit in wiring harness
  • Air conditioner pressure sensor malfunction
  • Poor contact in connectors
  • Low refrigerant level

How to Fix

  1. Check the refrigerant level in the system
  2. Inspect the sensor wiring harness and connectors for damage.
  3. Check the resistance of the pressure sensor
  4. Replace pressure sensor if necessary
  5. Clear error codes and check system operation

Related codes

B1857B1859P0532

FAQ

What does the B1858 code mean?

B1858 is an OBD-II diagnostic trouble code that indicates: Climate Control A/C Pressure Switch Circuit Failure

What causes a B1858 error code?

The most common causes of B1858 include: Open or short circuit in wiring harness; Air conditioner pressure sensor malfunction; Poor contact in connectors; Low refrigerant level.

How do I fix a B1858 diagnostic trouble code?

To fix B1858: Check the refrigerant level in the system. Inspect the sensor wiring harness and connectors for damage.. Check the resistance of the pressure sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1858?

Limited driving only, diagnose soon

How much does it cost to fix B1858?

The estimated repair cost for B1858 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat