OBD Guide

U0043

Vehicle Communication Bus B (-) Low

U0043 is an OBD-II diagnostic trouble code meaning: Vehicle Communication Bus B (-) Low. Common causes: broken or damaged communication bus wires, short circuit in the communication bus circuit. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Check Engine light comes on
  • Malfunction of vehicle electronic systems
  • Problems with diagnostics via OBD-II
  • Unstable operation of the dashboard

Causes

  • Broken or damaged communication bus wires
  • Short circuit in the communication bus circuit
  • Malfunction of one of the electronic modules
  • Poor contact in communication bus connectors
  • Problems with power supply of electronic modules

How to Fix

  1. Check the integrity of the communication bus wires
  2. Check connections and connectors of the communication bus
  3. Diagnose electronic modules for faults
  4. Check power supply of electronic modules
  5. Repair only from an authorized dealer

Related codes

Error U0043 by Vehicle Brand

FAQ

What does the U0043 code mean?

U0043 is an OBD-II diagnostic trouble code that indicates: Vehicle Communication Bus B (-) Low

What causes a U0043 error code?

The most common causes of U0043 include: Broken or damaged communication bus wires; Short circuit in the communication bus circuit; Malfunction of one of the electronic modules; Poor contact in communication bus connectors.

How do I fix a U0043 diagnostic trouble code?

To fix U0043: Check the integrity of the communication bus wires. Check connections and connectors of the communication bus. Diagnose electronic modules for faults. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U0043?

Yes, but get it checked soon

How much does it cost to fix U0043?

The estimated repair cost for U0043 is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat