OBD Guide

U0099

Vehicle Communication Bus H (-) High

U0099 is an OBD-II diagnostic trouble code meaning: Vehicle Communication Bus H (-) High. Common causes: open or short circuit in wiring harness, damage to communication bus connectors. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–56 (est.)

Symptoms

  • Check Engine light comes on
  • Incorrect operation of the vehicle's electronic systems
  • Loss of communication between modules
  • Reduced engine performance
  • Errors in other systems

Causes

  • Open or short circuit in wiring harness
  • Damage to communication bus connectors
  • Malfunction of one of the control modules
  • Grounding problems
  • Electromagnetic interference

How to Fix

  1. Check the integrity of the communication bus wiring harness
  2. Inspect connectors for corrosion or damage
  3. Check module grounding
  4. Scan all modules for errors
  5. Replace damaged components if necessary

Related codes

Error U0099 by Vehicle Brand

FAQ

What does the U0099 code mean?

U0099 is an OBD-II diagnostic trouble code that indicates: Vehicle Communication Bus H (-) High

What causes a U0099 error code?

The most common causes of U0099 include: Open or short circuit in wiring harness; Damage to communication bus connectors; Malfunction of one of the control modules; Grounding problems.

How do I fix a U0099 diagnostic trouble code?

To fix U0099: Check the integrity of the communication bus wiring harness. Inspect connectors for corrosion or damage. Check module grounding. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U0099?

Limited driving only, diagnose soon

How much does it cost to fix U0099?

The estimated repair cost for U0099 is $6–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat