OBD Guide
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U2109

Lost Communications With Powertrain Multiple Control System

U2109 is an OBD-II diagnostic trouble code meaning: Lost Communications With Powertrain Multiple Control System. Common causes: problems with the can bus (open or short circuit), control module (pcm) malfunction. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • Check Engine Light Is On
  • The car goes into emergency mode
  • Reduced engine power
  • Problems with gear shifting (on automatic)
  • Unstable engine operation

Causes

  • Problems with the CAN bus (open or short circuit)
  • Control module (PCM) malfunction
  • Wiring harness damage
  • Problems with module power supply
  • Corrosion of connectors

How to Fix

  1. Check the integrity of the CAN bus
  2. Inspect connectors and wiring harnesses
  3. Check power supply to control modules
  4. Read error codes of all modules
  5. Replace the PCM if necessary

Related codes

U2100U2101U2102

FAQ

What does the U2109 code mean?

U2109 is an OBD-II diagnostic trouble code that indicates: Lost Communications With Powertrain Multiple Control System

What causes a U2109 error code?

The most common causes of U2109 include: Problems with the CAN bus (open or short circuit); Control module (PCM) malfunction; Wiring harness damage; Problems with module power supply.

How do I fix a U2109 diagnostic trouble code?

To fix U2109: Check the integrity of the CAN bus. Inspect connectors and wiring harnesses. Check power supply to control modules. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U2109?

Yes, but get it checked soon

How much does it cost to fix U2109?

The estimated repair cost for U2109 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat