OBD Guide

U18A9

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

U18A9 is an OBD-II diagnostic trouble code meaning: Lost Communication With Transmission Range Control Module On Chassis Expansion CAN Bus. Common causes: open or short circuit in the can bus wiring, 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

  • Check Engine light comes on
  • The car goes into emergency mode
  • Incorrect operation of the gearbox
  • Lack of response to gear shifting
  • Power Loss

Causes

  • Open or short circuit in the CAN bus wiring
  • Range control module malfunction
  • Module power problems
  • Poor contact in connectors
  • Engine control unit malfunction

How to Fix

  1. Check the integrity of the CAN bus wiring
  2. Check power and grounding of the range control module
  3. Inspect connectors for corrosion or damage
  4. Scan other modules for communication errors
  5. Replace the range control module if necessary

Related codes

FAQ

What does the U18A9 code mean?

U18A9 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Transmission Range Control Module On Chassis Expansion CAN Bus

What causes a U18A9 error code?

The most common causes of U18A9 include: Open or short circuit in the CAN bus wiring; Range control module malfunction; Module power problems; Poor contact in connectors.

How do I fix a U18A9 diagnostic trouble code?

To fix U18A9: Check the integrity of the CAN bus wiring. Check power and grounding of the range control module. Inspect connectors for corrosion or damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18A9?

Do not drive — repair immediately

How much does it cost to fix U18A9?

The estimated repair cost for U18A9 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat