OBD Guide
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B278B

Electric Compressor High Voltage

B278B is an OBD-II diagnostic trouble code meaning: Electric Compressor High Voltage. Common causes: electric compressor malfunction, wiring harness damage. Estimated repair cost: $167–556.

Severity
🔴 High
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$167–556 (est.)

Symptoms

  • Air conditioner doesn't work
  • Check Engine light comes on
  • Reduced efficiency of the climate control system

Causes

  • Electric compressor malfunction
  • Wiring harness damage
  • Problems with the control unit
  • Short circuit in the circuit

How to Fix

  1. Check the voltage in the compressor circuit
  2. Inspect the wiring harness for damage
  3. Test the electric compressor
  4. Replace faulty components
  5. Reset the error and check the system

Related codes

B278AB278CP0562

FAQ

What does the B278B code mean?

B278B is an OBD-II diagnostic trouble code that indicates: Electric Compressor High Voltage

What causes a B278B error code?

The most common causes of B278B include: Electric compressor malfunction; Wiring harness damage; Problems with the control unit; Short circuit in the circuit.

How do I fix a B278B diagnostic trouble code?

To fix B278B: Check the voltage in the compressor circuit. Inspect the wiring harness for damage. Test the electric compressor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B278B?

Limited driving only, diagnose soon

How much does it cost to fix B278B?

The estimated repair cost for B278B is $167–556. Actual cost depends on your vehicle, location, and labor rates.

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