OBD Guide
ENFRDEESPT

P1B78

Hybrid/Electric Vehicle Battery 50 Circuit Performance

P1B78 is an OBD-II diagnostic trouble code meaning: Hybrid/Electric Vehicle Battery 50 Circuit Performance. Common causes: high voltage battery fault, problems with the battery management system. Estimated repair cost: $167–889.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$167–889 (est.)

Symptoms

  • Reduced vehicle power
  • Increased fuel consumption (for hybrids)
  • Check Engine Light Illuminated
  • Limitation of operation in electric mode
  • Error messages on the dashboard

Causes

  • High voltage battery fault
  • Problems with the battery management system
  • Wiring harness damage
  • Corrosion or poor connections
  • Battery sensor malfunction

How to Fix

  1. High voltage battery diagnostics
  2. Checking the Battery Management System
  3. Inspect the wiring harness and connections
  4. Battery Sensor Testing
  5. Repair or replacement of faulty components
  6. Repair only from an authorized dealer

Related codes

P1B77P1B79P0A80

FAQ

What does the P1B78 code mean?

P1B78 is an OBD-II diagnostic trouble code that indicates: Hybrid/Electric Vehicle Battery 50 Circuit Performance

What causes a P1B78 error code?

The most common causes of P1B78 include: High voltage battery fault; Problems with the battery management system; Wiring harness damage; Corrosion or poor connections.

How do I fix a P1B78 diagnostic trouble code?

To fix P1B78: High voltage battery diagnostics. Checking the Battery Management System. Inspect the wiring harness and connections. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1B78?

Do not drive — repair immediately

How much does it cost to fix P1B78?

The estimated repair cost for P1B78 is $167–889. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat