OBD Guide

U1861

Battery Charger Control Module Lost Communication With Engine Control Module

U1861 is an OBD-II diagnostic trouble code meaning: Battery Charger Control Module Lost Communication With Engine Control Module. Common causes: broken or damaged can bus wires, disconnected or oxidized connector contacts. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Check Engine light is on
  • Incorrect battery charge
  • Hybrid system power reduction (if equipped)
  • Switching to emergency mode
  • Errors in other on-board computer systems

Causes

  • Broken or damaged CAN bus wires
  • Disconnected or oxidized connector contacts
  • Charging control module malfunction
  • Problems with on-board voltage
  • Software failure in one of the modules

How to Fix

  1. Check the integrity of the CAN bus wiring
  2. Inspect and clean the connector contacts
  3. Check the voltage in the on-board network
  4. Read error codes in related systems
  5. Diagnose the charging control module

Related codes

FAQ

What does the U1861 code mean?

U1861 is an OBD-II diagnostic trouble code that indicates: Battery Charger Control Module Lost Communication With Engine Control Module

What causes a U1861 error code?

The most common causes of U1861 include: Broken or damaged CAN bus wires; Disconnected or oxidized connector contacts; Charging control module malfunction; Problems with on-board voltage.

How do I fix a U1861 diagnostic trouble code?

To fix U1861: Check the integrity of the CAN bus wiring. Inspect and clean the connector contacts. Check the voltage in the on-board network. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1861?

Yes, but get it checked soon

How much does it cost to fix U1861?

The estimated repair cost for U1861 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat