AutoCodes – Generic – U129E

U129E Code - Lost Communication With PCU

Quick Answer

The Controller Area Network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (F-CAN_H and F-CAN_L). Common causes include Faulty Keyless Access/TPMS Control Unit, Keyless Access/TPMS Control Unit harness is open or shorted, Keyless Access/TPMS Control Unit circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: U129E indicates Lost Communication With PCU.
Common causes: Common causes include Faulty Keyless Access/TPMS Control Unit, Keyless Access/TPMS Control Unit harness is open or shorted, Keyless Access/TPMS Control Unit circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 4,495

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 12, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code U129E Description

The Controller Area Network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (F-CAN_H and F-CAN_L). When the Powertrain Control Module (PCM) does not receive the signals from the Keyless Access/TPMS Control Unit via the F-CAN lines for a set time, the PCM detects a malfunction and stores a Diagnostic Trouble Code (DTC).

OBDII Code U129E - Lost Communication With PCU - AutoCodes.com — U129E Code - Lost Communication With PCU

What does this mean?

What are the Possible Causes of the DTC U129E?

Faulty Keyless Access/TPMS Control Unit
Keyless Access/TPMS Control Unit harness is open or shorted
Keyless Access/TPMS Control Unit circuit poor electrical connection
Faulty Powertrain Control Module (PCM)

How to Fix the DTC U129E?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U129E code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the U129E code?

Need more information on how to fix the U129E code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U129E code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

U129E Acura — Lost Communication With PCU
U129E Honda — Lost Communication With PCU

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about U129E Code

What does the OBDII code U129E mean?

U129E indicates a loss of communication with the Powertrain Control Unit (PCU), which can disrupt the vehicle's performance and diagnostics.

What are the common symptoms of a U129E code?

Common symptoms include poor engine performance, reduced fuel efficiency, warning lights on the dashboard, and the inability to communicate with the vehicle's diagnostic system.

What could cause a U129E code to appear?

Causes may include a faulty PCU, damaged wiring or connectors, poor ground connections, or issues with other modules that communicate with the PCU.

How can I diagnose a U129E code?

Start by checking the vehicle's wiring and connectors for damage or corrosion. Then, use a scan tool to verify the code and check for other related codes that may provide additional context.

What are some common repair solutions for a U129E code?

Repairs may involve fixing or replacing damaged wiring, repairing or replacing the PCU, or ensuring proper ground connections and communication between modules.

Can a dead battery cause a U129E code?

Yes, a dead or weak battery can lead to communication issues between the PCU and other modules, potentially triggering the U129E code.

Is it safe to drive a vehicle with a U129E code?

It may be unsafe to drive, as the vehicle may exhibit poor performance or engine issues. It's best to diagnose and repair the problem before continuing to drive.

How do I clear the U129E code after repairs?

Use an OBDII scanner to clear the code after making the necessary repairs. However, ensure that the underlying issue is resolved, as the code may return if the problem persists.

Will a U129E code affect my vehicle's emissions?

Yes, since the PCU plays a crucial role in managing engine performance and emissions, a U129E code can potentially lead to increased emissions due to improper fuel management or engine operation.