OBD Guide

U2105

Lost Communications with Engine Control Module

U2105 is an OBD-II diagnostic trouble code meaning: Lost Communications with Engine Control Module. Common causes: open or short circuit in the can bus, engine ecu malfunction. Estimated repair cost: $56–333.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–333 (est.)

Symptoms

  • Check Engine light comes on
  • Loss of engine power
  • Incorrect operation of other systems (ABS, transmission, etc.)
  • The car may go into emergency mode
  • Problems starting the engine

Causes

  • Open or short circuit in the CAN bus
  • Engine ECU malfunction
  • Problems with ECU power supply
  • Corroded or damaged connectors
  • Wiring Harness Problems

How to Fix

  1. Check the integrity of the CAN bus
  2. Check power supply and grounding of the ECU
  3. Inspect the ECU connectors for damage
  4. Check wiring harness for damage
  5. If necessary, replace the ECU

Related codes

FAQ

What does the U2105 code mean?

U2105 is an OBD-II diagnostic trouble code that indicates: Lost Communications with Engine Control Module

What causes a U2105 error code?

The most common causes of U2105 include: Open or short circuit in the CAN bus; Engine ECU malfunction; Problems with ECU power supply; Corroded or damaged connectors.

How do I fix a U2105 diagnostic trouble code?

To fix U2105: Check the integrity of the CAN bus. Check power supply and grounding of the ECU. Inspect the ECU connectors for damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U2105?

Do not drive — repair immediately

How much does it cost to fix U2105?

The estimated repair cost for U2105 is $56–333. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat