OBD Guide

U1850

Drive Motor Control Module 2 Lost Communication With Transmission Control Module

U1850 is an OBD-II diagnostic trouble code meaning: Drive Motor Control Module 2 Lost Communication With Transmission Control Module. Common causes: broken or damaged can bus wires, poor contact in ecm or tcm connectors. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • The car goes into emergency mode
  • Gear shifting problems
  • Check Engine light comes on
  • Reduced engine power
  • Unstable operation at idle

Causes

  • Broken or damaged CAN bus wires
  • Poor contact in ECM or TCM connectors
  • Transmission control module malfunction
  • Problems with power supply or grounding of modules
  • Software error in one of the modules

How to Fix

  1. Check the integrity of the CAN bus wiring
  2. Inspect ECM and TCM connectors for oxidation
  3. Check power supply and grounding of modules
  4. Scan both modules for additional errors
  5. If necessary, replace the faulty module

Related codes

FAQ

What does the U1850 code mean?

U1850 is an OBD-II diagnostic trouble code that indicates: Drive Motor Control Module 2 Lost Communication With Transmission Control Module

What causes a U1850 error code?

The most common causes of U1850 include: Broken or damaged CAN bus wires; Poor contact in ECM or TCM connectors; Transmission control module malfunction; Problems with power supply or grounding of modules.

How do I fix a U1850 diagnostic trouble code?

To fix U1850: Check the integrity of the CAN bus wiring. Inspect ECM and TCM connectors for oxidation. Check power supply and grounding of modules. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1850?

Limited driving only, diagnose soon

How much does it cost to fix U1850?

The estimated repair cost for U1850 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat