OBD Guide
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B27C4

A/C Unit Case Temperature Sensor Low

B27C4 is an OBD-II diagnostic trouble code meaning: A/C Unit Case Temperature Sensor Low. Common causes: evaporator temperature sensor malfunction, open or short circuit in the circuit. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • No cooling
  • Spontaneous shutdown of the air conditioner
  • Unstable climate control operation

Causes

  • Evaporator temperature sensor malfunction
  • Open or short circuit in the circuit
  • Poor contact in connectors
  • Malfunction of the climate control control unit

How to Fix

  1. Check sensor resistance at different temperatures
  2. Inspect the wiring harness and connectors
  3. Check reference voltage and continuity
  4. Replace the faulty sensor if necessary

Related codes

B2773B2476B2475

FAQ

What does the B27C4 code mean?

B27C4 is an OBD-II diagnostic trouble code that indicates: A/C Unit Case Temperature Sensor Low

What causes a B27C4 error code?

The most common causes of B27C4 include: Evaporator temperature sensor malfunction; Open or short circuit in the circuit; Poor contact in connectors; Malfunction of the climate control control unit.

How do I fix a B27C4 diagnostic trouble code?

To fix B27C4: Check sensor resistance at different temperatures. Inspect the wiring harness and connectors. Check reference voltage and continuity. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B27C4?

Yes, but get it checked soon

How much does it cost to fix B27C4?

The estimated repair cost for B27C4 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat