OBD Guide
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U18D3

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

U18D3 is an OBD-II diagnostic trouble code meaning: Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus. Common causes: open or short circuit in the can bus circuit, transmission range selector module malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • The Check Engine light comes on
  • The gearbox goes into emergency mode
  • The current transmission mode is not displayed on the instrument panel
  • Gear shifting problems
  • Lack of response to selector switch

Causes

  • Open or short circuit in the CAN bus circuit
  • Transmission Range Selector Module Malfunction
  • Module power problems
  • Corrosion or poor contact in connectors
  • Main ECU malfunction

How to Fix

  1. Conduct CAN bus diagnostics using an oscilloscope
  2. Check the integrity of the wiring and connections of the module
  3. Check the power and ground of the range selector module
  4. Replacing the transmission range selector module if necessary
  5. Update ECU software if necessary

Related codes

U18D1U18D2U18D4

FAQ

What does the U18D3 code mean?

U18D3 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Transmission Range Selector Control Module On Powertrain Expansion CAN Bus

What causes a U18D3 error code?

The most common causes of U18D3 include: Open or short circuit in the CAN bus circuit; Transmission Range Selector Module Malfunction; Module power problems; Corrosion or poor contact in connectors.

How do I fix a U18D3 diagnostic trouble code?

To fix U18D3: Conduct CAN bus diagnostics using an oscilloscope. Check the integrity of the wiring and connections of the module. Check the power and ground of the range selector module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U18D3?

Limited driving only, diagnose soon

How much does it cost to fix U18D3?

The estimated repair cost for U18D3 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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