OBD Guide
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U1815

Lost Communication With Drive Motor Control Module 1 On Bus B

U1815 is an OBD-II diagnostic trouble code meaning: Lost Communication With Drive Motor Control Module 1 On Bus B. Common causes: broken or damaged can bus wires, oxidation of contacts in connectors. Estimated repair cost: $56–278.

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

Symptoms

  • Check Engine light comes on
  • The car goes into emergency mode
  • Reduced engine power
  • Problems starting the engine
  • Unstable engine operation

Causes

  • Broken or damaged CAN bus wires
  • Oxidation of contacts in connectors
  • Engine control module malfunction
  • Module power problems
  • Software failures in the ECU

How to Fix

  1. Check the integrity of the CAN bus wiring
  2. Inspect and clean connector contacts
  3. Check the power and ground of the control module
  4. Scan other modules for errors
  5. If necessary, replace the control module

Related codes

U1816U1814U1817

FAQ

What does the U1815 code mean?

U1815 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Drive Motor Control Module 1 On Bus B

What causes a U1815 error code?

The most common causes of U1815 include: Broken or damaged CAN bus wires; Oxidation of contacts in connectors; Engine control module malfunction; Module power problems.

How do I fix a U1815 diagnostic trouble code?

To fix U1815: Check the integrity of the CAN bus wiring. Inspect and clean connector contacts. Check the power and ground of the control module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1815?

Limited driving only, diagnose soon

How much does it cost to fix U1815?

The estimated repair cost for U1815 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat