OBD Guide

B0978

Accessory Indicator Control Circuit

B0978 is an OBD-II diagnostic trouble code meaning: Accessory Indicator Control Circuit. Common causes: open or short circuit in wiring harness, blown fuse. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$6–56 (est.)

Symptoms

  • The accessory indicator does not work
  • Flashing or unstable indicator
  • No dashboard backlight

Causes

  • Open or short circuit in wiring harness
  • Blown fuse
  • Control unit malfunction
  • Problems with contacts in the circuit

How to Fix

  1. Check the fuses associated with the indicator circuit
  2. Inspect the wiring harness for damage
  3. Check contacts and connectors in the circuit
  4. Test the control unit for faults
  5. Replace faulty components

Related codes

Error B0978 by Vehicle Brand

FAQ

What does the B0978 code mean?

B0978 is an OBD-II diagnostic trouble code that indicates: Accessory Indicator Control Circuit

What causes a B0978 error code?

The most common causes of B0978 include: Open or short circuit in wiring harness; Blown fuse; Control unit malfunction; Problems with contacts in the circuit.

How do I fix a B0978 diagnostic trouble code?

To fix B0978: Check the fuses associated with the indicator circuit. Inspect the wiring harness for damage. Check contacts and connectors in the circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B0978?

Do not drive — repair immediately

How much does it cost to fix B0978?

The estimated repair cost for B0978 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat