OBD Guide

U18D1

Lost Communication With Transmission Range Control Module On Powertrain Expansion CAN Bus

U18D1 is an OBD-II diagnostic trouble code meaning: Lost Communication With Transmission Range Control Module On Powertrain Expansion CAN Bus. Common causes: broken or damaged can bus wires, transmission range control module malfunction. Estimated repair cost: $56–167.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–167 (est.)

Symptoms

  • Inability to change gears
  • Check Engine Light Is On
  • The car goes into emergency mode
  • No display of the current gear on the instrument panel

Causes

  • Broken or damaged CAN bus wires
  • Transmission Range Control Module Malfunction
  • Module power problems
  • Corrosion or poor contact in connectors
  • Engine control unit malfunction

How to Fix

  1. Check the integrity of the CAN bus wiring
  2. Check power supply and grounding of the module
  3. Inspect connectors for corrosion
  4. Scan other modules for CAN bus errors
  5. If necessary, replace the transmission range control module

Related codes

FAQ

What does the U18D1 code mean?

U18D1 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Transmission Range Control Module On Powertrain Expansion CAN Bus

What causes a U18D1 error code?

The most common causes of U18D1 include: Broken or damaged CAN bus wires; Transmission Range Control Module Malfunction; Module power problems; Corrosion or poor contact in connectors.

How do I fix a U18D1 diagnostic trouble code?

To fix U18D1: Check the integrity of the CAN bus wiring. Check power supply and grounding of the module. Inspect connectors for corrosion. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18D1?

Do not drive — repair immediately

How much does it cost to fix U18D1?

The estimated repair cost for U18D1 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat