OBD Guide

U01B8

Lost Communication With Switch Input Module B

U01B8 is an OBD-II diagnostic trouble code meaning: Lost Communication With Switch Input Module B. Common causes: broken or damaged can bus wires, switch module b fault. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Some switches in the cabin do not work
  • Check Engine Light Is On
  • Errors in other CAN bus-related systems
  • Intermittent operation of related functions

Causes

  • Broken or damaged CAN bus wires
  • Switch module B fault
  • Module power problems
  • Corrosion of contacts or connectors
  • ECU malfunction

How to Fix

  1. Check the integrity of the CAN bus wires
  2. Diagnose switch module B
  3. Check the power supply and ground of the module
  4. Inspect connectors for corrosion
  5. If necessary, replace the switch module

Related codes

Error U01B8 by Vehicle Brand

FAQ

What does the U01B8 code mean?

U01B8 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Switch Input Module B

What causes a U01B8 error code?

The most common causes of U01B8 include: Broken or damaged CAN bus wires; Switch module B fault; Module power problems; Corrosion of contacts or connectors.

How do I fix a U01B8 diagnostic trouble code?

To fix U01B8: Check the integrity of the CAN bus wires. Diagnose switch module B. Check the power supply and ground of the module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U01B8?

Yes, but get it checked soon

How much does it cost to fix U01B8?

The estimated repair cost for U01B8 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat