OBD Guide
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U129E

Lost Communication With PCU

U129E is an OBD-II diagnostic trouble code meaning: Lost Communication With PCU. Common causes: open or short circuit in the can bus, pcu module malfunction. Estimated repair cost: $167–556.

Severity
🔴 High
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$167–556 (est.)

Symptoms

  • Check Engine light comes on
  • The car goes into emergency mode
  • Reduced engine power
  • Problems charging the hybrid battery
  • Disabling some electronic systems

Causes

  • Open or short circuit in the CAN bus
  • PCU module malfunction
  • PCU power supply problems
  • Corroded or damaged connectors
  • Software failure in ECU or PCU

How to Fix

  1. Check the integrity of the CAN bus between the ECU and PCU
  2. Check power supply and ground of PCU module
  3. Inspect connectors for corrosion or damage
  4. Perform diagnostics on the PCU module
  5. If necessary, replace the PCU or update its firmware

Related codes

U129FU0100U0121

FAQ

What does the U129E code mean?

U129E is an OBD-II diagnostic trouble code that indicates: Lost Communication With PCU

What causes a U129E error code?

The most common causes of U129E include: Open or short circuit in the CAN bus; PCU module malfunction; PCU power supply problems; Corroded or damaged connectors.

How do I fix a U129E diagnostic trouble code?

To fix U129E: Check the integrity of the CAN bus between the ECU and PCU. Check power supply and ground of PCU module. Inspect connectors for corrosion or damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U129E?

Limited driving only, diagnose soon

How much does it cost to fix U129E?

The estimated repair cost for U129E is $167–556. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat