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Yanmar 3TNV86, 4TNV86 Engine Control Module (ECM) 2014-2021: OEM 129C26-78000

YANMAR 3TNV86, 4TNV86 ENGINE CONTROL MODULE (ECM) 2014-2021: OEM 129C26-78000

Shipping ICON

ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY

WARRANTY ICON

WARRANTY
1M MILES OR 1 YEAR

$1,195.00

AVAILABILITY IN STOCK
OEM NUMBER129C26-78000
PART TYPEEngine Control Module (ECM)
BRANDTamerx Diesel Products
ENGINE MAKEYanmar
ENGINE TYPE3TNV86, 4TNV86
YEAR2014-2021
PART NUMBER129C26-78000RM
APPLICATION NOTESTier 4 Final

PRODUCT DESCRIPTION

This is a New, Tamerx Engine Control Module (ECM), Tamerx part number 129C26-78000RM ( OEM Part Number 129C26-78000 ).This part is primarily made for a Yanmar 3TNV86, 4TNV86, production years 2014-2021, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here

OEM NUMBERS

Primary OEM129C26-78000
Additional OEM129C26-78000

ADDITIONAL DETAILS

CONDITIONNew
UPC / Barcode00840490542419
WEIGHT5.00 LBS

SHIPPING OPTIONS

Ship Weight : 5.00 LBS
UPS Ground, 2nd Day Air, Next Day Air

SHIPPING POLICY

Tamerx Diesel Products ships via UPS Ground. Next day air shipping can be arranged for a reasonable price of anywhere from $50.00 - $100.00 depending on the weight of the product and your location. We will do everything we can to make sure that you get the service you need. We understand how important it is to receive your order as quickly as possible.
In most cases Tamerx Diesel Products only needs one address, as long as your product is shipping to the same location as your billing information. In order to eliminate credit card fraud, your billing information must match the credit card you provide.

The terms, conditions, and details of our warranty vary from product to product. Specific warranty details can be found below.

Tamerx Diesel Products provides a replacement warranty on all of our parts. The duration and mileage limitations of the warranty vary by product and are specified on the product's detail page/item listing.

Please note that the warranty covers replacement of the part and the cost of shipping the replacement part to you only. It does not cover any shop, labor, towing, or any similar or related costs. This is not a "money back guarantee".

If you experience a problem with your part or it is not functioning properly, the correct warranty procedure is to call us at (510) 257-1777 (8:00 AM - 5:00 PM ET Monday through Friday). Be sure to have your order number and/or other relevant order information ready so we can easily locate your order and resolve your issue as quickly as possible. From that point, we will review with you any troubleshooting steps that may need to be taken and other areas or systems that can be checked to rule out external problems contributing to your part's issue. If a replacement is determined to be necessary, we will then arrange for your replacement part to ship out ASAP and issue any necessary return shipping labels and/or documents.

As is the case for the majority of the diesel products sold on Tamerx Diesel Products, your part's warranty is active as soon as you install it. In some other cases, warranty activation is contingent upon you sending us your core (i.e., your old part). Tamerx Diesel Products will provide you a return shipping label for parts that have a warranty with a core return condition. When we have received your core return, the part's warranty coverage begins. We reserve the right to void the product warranty if your core is not received within the allotted time, or if it isn't received at all. If the warranty for the diesel part you are purchasing has a core return requirement, it will be clearly noted on the product detail page/item listing.

What is a Core Charge?

A core charge (also called "core deposit") is similar to the deposit you might pay for a can or bottle of soda and is a standard requirement in the auto parts industry. For example, in many states, to promote recycling, you pay a deposit when you purchase a can of soda and receive your deposit back when you return the empty can. Many automotive parts have a core charge, or core price, that works in essentially the same way as a soda can deposit.

30 Day Core Charge Hold

You authorize Tamerx Diesel Products, to hold your credit card for the specified core charge amount and that you agree to return your core with 30 days of receiving the purchased part. When we have received your core return, the hold is released and the core charge payment is canceled.

The customer, or parts buyer, is responsible for any shipping costs associated with core returns unless otherwise specified in the product listing/detail page. Tamerx Diesel Products offers prepaid UPS shipping labels (SKU numbers UPS-CR1 and UPS-CR2) for use in returning your core that are available for purchase on our website during your shopping/order process.

The shipping label you will need to use for the core return is dependent upon what part you are purchasing. UPS-CR1 is good for cores weighing up to 20 pounds. UPS-CR2 is appropriate for shipping cores weighing 21 pounds or more. You must include enough information with the core return that clearly identifies it as a.) a Core Return, and b.) contains enough information we can use to clearly associate the core return with your order. Including a copy of the invoice or packing slip that came with the original shipment, clearly marked "Core Return", is ideal. Alternately, you can include a note marked as "Core Return" that includes your order number, full name and address, and phone number or other contact information. Failure to include this information with your returned core will most likely delay any due core credit being issued and/or delay any applicable warranty activation. Core returns need to be for the exact part purchased and cannot be damaged. Substituting another part in place of the part you have purchased is not acceptable.

All fluids must be drained.

If you have purchased a set or a parts package, you will need to return cores for all components of the set. For example, if you have purchaed a high pressure oil pump with an IPR valve, you will need to return both HPOP and IPR valve cores to receive proper credit. If you have purchased an EGR cooler/EGR valve package, your core return must consist of an EGR cooler core and an EGR valve core, or core credit will not be given.

Core Charges are often mandated by state legislature, and, as such, the actual core charge and taxes on the charge may vary depending on the state in which you buy your part. The Tamerx Diesel Products core charge presented to you online today with your item is representative of the most common core charge.


Precise engine management begins with the Yanmar 3TNV86, 4TNV86 Engine Control Module (ECM) 2014–2021, OEM Part Number 129C26-78000. Designed for compatibility with select Yanmar 3TNV86 and 4TNV86 engines, this ECM controls critical functions such as fuel delivery, timing, and system diagnostics. Manufactured to meet OEM specifications, it ensures accurate fitment and reliable communication with onboard sensors and components. A faulty ECM can lead to starting issues, irregular engine operation, or persistent fault codes, making proper replacement essential. Tamerx Diesel Products LLC provides dependable diesel components to help keep your Yanmar engine operating smoothly and consistently.

FITMENT CHART

YEARMAKEENGINE(S)
2014Yanmar 3TNV86 4TNV86
2015Yanmar 3TNV86 4TNV86
2016Yanmar 3TNV86 4TNV86
2017Yanmar 3TNV86 4TNV86
2018Yanmar 3TNV86 4TNV86
2019Yanmar 3TNV86 4TNV86
2020Yanmar 3TNV86 4TNV86
2021Yanmar 3TNV86 4TNV86

PEOPLE ALSO ASKS | BLOG(S)

Modern Yanmar diesel engines rely on electronic management for precise operation, and the Yanmar 3TNV86, 4TNV86 Engine Control Module (ECM) OEM 129C26-78000 serves as the central control unit. Designed for 2014–2021 applications, this module monitors and manages critical engine functions to ensure efficient and reliable performance.

The primary role of the ECM is to process input data from various engine sensors and make real-time adjustments to optimize operation. It acts as the “brain” of the engine’s electronic system.

The Yanmar ECM OEM 129C26-78000 is responsible for:

  • Controlling fuel injection timing and quantity
  • Monitoring engine speed and load conditions
  • Managing idle and throttle response
  • Regulating emissions-related components
  • Storing diagnostic fault codes

The ECM continuously receives signals from sensors that measure temperature, pressure, airflow, and other operating conditions. Using this information, it adjusts fuel delivery and other parameters to maintain stable combustion and proper engine function.

If the ECM detects irregular readings or component failures, it can trigger warning indicators and log diagnostic codes for troubleshooting.

Engineered specifically for Yanmar 3TNV86 and 4TNV86 engines, the OEM 129C26-78000 ECM ensures proper communication between sensors, actuators, and control systems.

When functioning correctly, the ECM supports smooth engine operation, controlled fuel delivery, and dependable performance across a wide range of applications.

The Engine Control Module (ECM) is the central computer that manages fuel delivery, ignition timing, emissions systems, and many other engine functions. When it fails, multiple systems can be affected at once.

The main cause of ECM failure is electrical damage.

Voltage spikes, short circuits, or poor grounding can damage the delicate internal circuitry inside the module. Because the ECM relies on consistent voltage, irregular electrical supply can gradually weaken components or cause sudden failure.

Other common contributing factors include:

  • Water intrusion or moisture exposure
  • Corroded wiring or connectors
  • Faulty alternator overcharging
  • Jump-starting errors
  • Heat exposure from engine bay conditions
  • Battery connection issues

Water damage is especially harmful. Even small amounts of moisture can corrode internal circuit boards and disrupt communication with sensors.

Heat is another major factor. Continuous exposure to high engine temperatures can stress internal electronics over time.

In some cases, a failing sensor or shorted component elsewhere in the system can overload the ECM and lead to internal damage.

Routine inspection of wiring, maintaining healthy battery and charging systems, and addressing electrical issues quickly can significantly reduce the risk of premature ECM failure.

Yes, the Yanmar 129C26-78000 ECM is designed to connect with the original engine sensors and wiring harness.

After installation, confirming proper function with diagnostic testing is recommended to ensure correct integration.

The Yanmar 129C26-78000 ECM manages key engine functions including fuel delivery and timing on compatible models.

Yes, a malfunctioning Yanmar 129C26-78000 ECM can generate diagnostic trouble codes and disrupt engine control.