Skip to Product Info
    • terminatorxmax_v41974.jpg
    • 550-9281966.jpg
    • 558-405_01183051966.jpg
    • 558-405_02183051966.jpg
    • caps1966.jpg
    • crankid1978.png
    • injectorid1978.png
    • terminatorxmaxdems_11975.jpg
    • terminatorxmaxdems_21975.jpg
    • wire11966.jpg
    • wire21966.jpg
    • wire31966.jpg
    • 554-153_01_P04_ANG.jpg
    • 554-153_02_P01_FRO.jpg
    • 554-153_03_P01_ANG.jpg
    • 554-153_04_P01_ANG.jpg
    • 554-153_06_P01_BOT.jpg
    • 554-153_07_P01_BOT.jpg
    • 554-153_08_P01_ANG.jpg
    • Terminator X Max Measurements - Side View.jpg
    • Terminator X Max Measurements - Top View.jpg
    • 554-153_01_P04_ANG.jpg
    • 554-153_02_P01_FRO.jpg
    • 554-153_03_P01_ANG.jpg
    • 554-153_04_P01_ANG.jpg
    • 554-153_06_P01_BOT.jpg
    • 554-153_07_P01_BOT.jpg
    • 554-153_08_P01_ANG.jpg
    • Terminator X Max Measurements - Side View.jpg
    • Terminator X Max Measurements - Top View.jpg
    Sale!

    Holley EFI Holley EFI Terminator X Max - Gen IV 4.8/5.3/6.0 GM Truck Engines and LS2/LS3 550-928

    Vendor: Holley EFI
    SKU: GVMR_550-928
    Save $207
    Sale Price $2,099.95 Regular Price $2,306.95
    Fast Fulfillment: In-stock parts typically ship same day or next business day.
    Free Shipping on Orders Over $99 | Excludes freight shipments
    Professional, Enthusiast-Driven Customer Support
    International Shipping Available - Contact Us!
    Payment & Security

    Payments are processed through secure, encrypted payment systems. Your credit card information is transmitted directly to the payment processor and is never stored or accessible by us.

    • Amazon
    • American Express
    • Apple Pay
    • Diners Club
    • Discover
    • Google Pay
    • Mastercard
    • PayPal
    • Shop Pay
    • Venmo
    • Visa
    Share to:
    Terminator X Max features real-time fuel learn, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs. The inputs and outputs are ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. Part number 550-928 also has 4L60E or 4L80E Transmission control and Drive-By Wire Throttle Body control. Terminator X Max comes fully loaded with base maps for common LS engine combinations to get you out of the garage and on the road/track fast. The 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions. Also included is Holley EFI's industry-leading, easy-to-use software suite that allows full laptop access for advanced users. Whether you are building a budget beater or a boosted race car, Terminator X MAX has the features and technology you need at a price that won't break the bank.


    Holley EFI Holley EFI Terminator X Max - Gen IV 4.8/5.3/6.0 GM Truck Engines and LS2/LS3 550-928


    Specifications:

    10429 Yes
    10431 Yes
    Brand Holley EFI
    10423 Yes
    Category Air and Fuel Delivery
    10438 Yes
    Crank Reluctor 58x
    10430 Yes
    10437 No
    Drive-By-Wire Yes
    10442 Yes
    10418 Yes
    10428 Yes
    Emission Code 3
    10433 Yes
    7246 No
    10417 No
    906 No
    10425 No
    8922 No
    3390 Performance
    Handheld Included Yes
    909 No
    10422 Yes
    Ignition Type GM LS 58x
    10432 Yes
    Injector Connector USCAR (EV6)
    9780 No
    10427 Yes
    MAP Sensor 1bar
    30 No
    10420 Yes
    Product Type EFI System
    10421 Yes
    10434 Yes
    Terminator LS Options Fuel, Spark, Drive-by-Wire, Transmission
    918 No
    Transmission 4L60E/4L80E
    10435 Yes
    Warning California Proposition 65
    10419 Yes
    10429 Yes
    10431 Yes
    Brand Holley EFI
    10423 Yes
    Category Air and Fuel Delivery
    10438 Yes
    Crank Reluctor 58x
    10430 Yes
    10437 No
    Drive-By-Wire Yes
    10442 Yes
    10418 Yes
    10428 Yes
    Emission Code 3
    10433 Yes
    7246 No
    10417 No
    906 No
    10425 No
    8922 No
    3390 Performance
    Handheld Included Yes
    909 No
    10422 Yes
    Ignition Type GM LS 58x
    10432 Yes
    Injector Connector USCAR (EV6)
    9780 No
    10427 Yes
    MAP Sensor 1bar
    30 No
    10420 Yes
    Product Type EFI System
    10421 Yes
    10434 Yes
    Terminator LS Options Fuel, Spark, Drive-by-Wire, Transmission
    918 No
    Transmission 4L60E/4L80E
    10435 Yes
    Warning California Proposition 65
    10419 Yes
    Description_INV TERMINATOR X MAX MPFI W/TRANS & DBW
    Description_ASC Not recommended for 4x4 applications with electronic transfer cases. Not compatible with 4L6X transmissions from model year 1995 or before due to year-by-year changes in converter lockup and downshift strategy. ECU is not recommended for marine applications, but can be used on off-road applications as long as you choose a safe location, keep it dry, protect from heat, and ensure proper wiring management.
    Description_DES Holley EFI Terminator X Max - Gen IV 4.8/5.3/6.0 GM Truck Engines and LS2/LS3
    Description_EXT 58x Crank - 4x Cam - EV6 Injectors - Drive-By-Wire Throttle Body and Transmission Control - 3.5 in. Touchscreen
    Description_MKT Take control of your LS engine with Terminator X Max. Don't settle for a junkyard ECU with a cumbersome tuning interface when you can have complete control of your engine, self-learning fuel strategies and the proven, race-winning technology of Holley EFI at a budget-friendly price.
    Description_MKT Terminator X Max features real-time fuel learn, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs. The inputs and outputs are ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. Part number 550-928 also has 4L60E or 4L80E Transmission control and Drive-By Wire Throttle Body control. Terminator X Max comes fully loaded with base maps for common LS engine combinations to get you out of the garage and on the road/track fast. The 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions. Also included is Holley EFI's industry-leading, easy-to-use software suite that allows full laptop access for advanced users. Whether you are building a budget beater or a boosted race car, Terminator X MAX has the features and technology you need at a price that won't break the bank.
    Description_FAB Designed for GM LS 4.8/5.3/6.0 LS Truck Engines and LS2/LS3 with 58x Crank, 4x Cam and 4L60E/4L80E transmissions, Drive-by wire throttle body control, and EV6 Injectors
    Description_FAB Real-time fuel map learn takes the guess work out of tuning your base fuel table
    Description_FAB High Impedance Injector Drivers will safely power most Stock LS injectors and Holley EFI Injectors. Injector support chart provided in the instructions (will not control Low Impedance Injectors)
    Description_FAB All of the new Terminator X Max systems utilize the Bosch LSU 4.9 wideband to relay AFR information to the ECU for accurate reading and precise tuning control
    Description_FAB On-Board 1bar MAP sensor is perfect for N/A or Nitrous engine combos. If your combination requires a 2+Bar, we recommend GM 12592525 and our adapter part number 558-416
    Description_FAB MAP Sensor vacuum hose adapters (1/8th – ¼ and 3/16ths)
    Description_FAB 4 Inputs – 12v, Ground, 5v, and Frequency for things such as additional pressure sensors, activation triggers for nitrous activation, or a trans brake
    Description_FAB 4 Outputs – Ground, PWM - for accessories such as fans, boost control, nitrous control, IAC Kit, and more
    Description_FAB Boost Control – Boost vs Time, Boost vs Gear, Boost vs RPM, Boost vs Speed, Boost Safeties
    Description_FAB Nitrous Control – Single Channel of Wet or Dry, Progressive or Non-Progressive, Rich/Lean Safeties, and target Closed Loop AFR
    Description_FAB Advanced Tables – 4x 1D Tables, 1x 1D per Gear Table, 4x 2D Tables, 1x 2D per Gear Table can be used for any custom tables you can dream up, such as Flex Fuel Sensor Offset Table, or a custom fuel or oil pressure safety
    Description_FAB On-Board Diagnostic LEDS for ECU Power – Engine Run – Wideband Status – TPS Calibration – Crank Signal –Cam Signal allow you to identify any critical engine issues at a glance
    Description_FAB The included 3.5" Touchscreen Handheld contains a calibration wizard that allows you to quickly build a base tune for any LS engine. Additionally the handheld provides internal data-logging and a fully customizable gauge display
    Description_FAB The compact ECU size allows you to mount it virtually anywhere, remember, diagnostic LEDS must face up
    Description_FAB Plug and play compatible with multiple Holley EFI accessories including our gauges, shift lights, various modules, and digital and pro dashes (Holley P/N's 553-106, 553-111, and 553-112)
    Description_FAB Free EFI Tuning Software for complete control of your Terminator X power plant
    Description_FAB Recommended Pedal part number - 10379038
    Description_FAB Includes: 58x/4x LS Engine Main Harness - EV6 Injector Harness - DBW Throttle Body Harness - 4L60E/4L80E Transmission Control Harness - Terminator X MAX ECU - ECU Main Power Harness - Bosch LSU 4.9 Wideband Oxygen Sensor - I/O Harness
    Description_INV TERMINATOR X MAX MPFI W/TRANS & DBW
    Description_ASC Not recommended for 4x4 applications with electronic transfer cases. Not compatible with 4L6X transmissions from model year 1995 or before due to year-by-year changes in converter lockup and downshift strategy. ECU is not recommended for marine applications, but can be used on off-road applications as long as you choose a safe location, keep it dry, protect from heat, and ensure proper wiring management.
    Description_DES Holley EFI Terminator X Max - Gen IV 4.8/5.3/6.0 GM Truck Engines and LS2/LS3
    Description_EXT 58x Crank - 4x Cam - EV6 Injectors - Drive-By-Wire Throttle Body and Transmission Control - 3.5 in. Touchscreen
    Description_MKT Take control of your LS engine with Terminator X Max. Don't settle for a junkyard ECU with a cumbersome tuning interface when you can have complete control of your engine, self-learning fuel strategies and the proven, race-winning technology of Holley EFI at a budget-friendly price.
    Description_MKT Terminator X Max features real-time fuel learn, high impedance injector drivers, an integrated 1bar MAP sensor, and 4 programmable inputs and outputs. The inputs and outputs are ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. Part number 550-928 also has 4L60E or 4L80E Transmission control and Drive-By Wire Throttle Body control. Terminator X Max comes fully loaded with base maps for common LS engine combinations to get you out of the garage and on the road/track fast. The 3.5" touch screen LCD handheld contains an easy to use calibration wizard as well as tuning and gauge display functions. Also included is Holley EFI's industry-leading, easy-to-use software suite that allows full laptop access for advanced users. Whether you are building a budget beater or a boosted race car, Terminator X MAX has the features and technology you need at a price that won't break the bank.
    Description_FAB Designed for GM LS 4.8/5.3/6.0 LS Truck Engines and LS2/LS3 with 58x Crank, 4x Cam and 4L60E/4L80E transmissions, Drive-by wire throttle body control, and EV6 Injectors
    Description_FAB Real-time fuel map learn takes the guess work out of tuning your base fuel table
    Description_FAB High Impedance Injector Drivers will safely power most Stock LS injectors and Holley EFI Injectors. Injector support chart provided in the instructions (will not control Low Impedance Injectors)
    Description_FAB All of the new Terminator X Max systems utilize the Bosch LSU 4.9 wideband to relay AFR information to the ECU for accurate reading and precise tuning control
    Description_FAB On-Board 1bar MAP sensor is perfect for N/A or Nitrous engine combos. If your combination requires a 2+Bar, we recommend GM 12592525 and our adapter part number 558-416
    Description_FAB MAP Sensor vacuum hose adapters (1/8th – ¼ and 3/16ths)
    Description_FAB 4 Inputs – 12v, Ground, 5v, and Frequency for things such as additional pressure sensors, activation triggers for nitrous activation, or a trans brake
    Description_FAB 4 Outputs – Ground, PWM - for accessories such as fans, boost control, nitrous control, IAC Kit, and more
    Description_FAB Boost Control – Boost vs Time, Boost vs Gear, Boost vs RPM, Boost vs Speed, Boost Safeties
    Description_FAB Nitrous Control – Single Channel of Wet or Dry, Progressive or Non-Progressive, Rich/Lean Safeties, and target Closed Loop AFR
    Description_FAB Advanced Tables – 4x 1D Tables, 1x 1D per Gear Table, 4x 2D Tables, 1x 2D per Gear Table can be used for any custom tables you can dream up, such as Flex Fuel Sensor Offset Table, or a custom fuel or oil pressure safety
    Description_FAB On-Board Diagnostic LEDS for ECU Power – Engine Run – Wideband Status – TPS Calibration – Crank Signal –Cam Signal allow you to identify any critical engine issues at a glance
    Description_FAB The included 3.5" Touchscreen Handheld contains a calibration wizard that allows you to quickly build a base tune for any LS engine. Additionally the handheld provides internal data-logging and a fully customizable gauge display
    Description_FAB The compact ECU size allows you to mount it virtually anywhere, remember, diagnostic LEDS must face up
    Description_FAB Plug and play compatible with multiple Holley EFI accessories including our gauges, shift lights, various modules, and digital and pro dashes (Holley P/N's 553-106, 553-111, and 553-112)
    Description_FAB Free EFI Tuning Software for complete control of your Terminator X power plant
    Description_FAB Recommended Pedal part number - 10379038
    Description_FAB Includes: 58x/4x LS Engine Main Harness - EV6 Injector Harness - DBW Throttle Body Harness - 4L60E/4L80E Transmission Control Harness - Terminator X MAX ECU - ECU Main Power Harness - Bosch LSU 4.9 Wideband Oxygen Sensor - I/O Harness


    Shipping Policy

    Last Updated: June 2026

    We're committed to getting your order to you as quickly and transparently as possible. Here's everything you need to know about how we ship.

    Order Processing Time

    In-stock orders are typically processed and shipped within 1–2 business days of receiving payment, unless otherwise noted on the product page.

    Orders placed on weekends or holidays will be processed on the next business day.

    Processing times are estimates and may vary during periods of high order volume, severe weather events, holidays, or circumstances beyond our control.

    Backordered Items & ETA Listings

    Some listings display an estimated ship date (ETA). These items are not in stock at the time of order and will not ship immediately.

    ETAs are provided by manufacturers and suppliers and are not guaranteed. Ship dates may change without notice.

    By placing an order for an ETA listing, you acknowledge and agree to the estimated timeframe displayed on the product page.

    If you need to cancel a backordered item, please refer to our Refund Policy for applicable cancellation fees.

    Order Cancellations

    Once an order is placed, cancellations are not guaranteed, as orders are sent to fulfillment quickly.

    If you need to cancel an order, contact us immediately at sales@berryperformancesales.com.

    If a cancellation is possible, applicable processing fees may apply in accordance with our Refund Policy.

    Orders that have already shipped cannot be cancelled and must go through our standard return process.

    Shipping Costs

    Shipping costs are calculated at checkout based on the shipping method selected, package weight and dimensions, and destination address.

    Available shipping options and costs will be displayed before you complete your purchase.

    Estimated Delivery Times

    Domestic orders typically arrive within 1–7 business days after shipment, depending on your location and the carrier.

    Delivery times are estimates only and are not guaranteed.

    Delays due to weather, carrier volume, customs processing, labor disruptions, or other circumstances beyond our control may occur.

    Tracking Information

    Once your order ships, you will receive a confirmation email with tracking information.

    If your tracking has not updated within 48 hours of receiving your shipping confirmation, please contact us.

    Shipping Address

    Please ensure your shipping address is accurate and complete before placing your order.

    If you need to update your address after placing an order, contact us immediately. We will do our best to accommodate your request, but address changes cannot be guaranteed once an order enters fulfillment.

    Berry Performance Sales is not responsible for orders shipped to incorrect or undeliverable addresses provided by the customer.

    We are unable to ship to P.O. Boxes. Please provide a physical delivery address at checkout.

    Signature Requirements

    Berry Performance Sales reserves the right to require an adult signature upon delivery for high-value orders.

    Freight Deliveries

    Freight shipments must be inspected at the time of delivery.

    Any visible damage, shortages, or discrepancies must be noted on the carrier's delivery receipt before signing.

    Failure to note damage or shortages at the time of delivery may limit or void the ability to file a freight damage claim.

    If your freight shipment arrives damaged, contact us within 48 hours of delivery.

    Lost or Stolen Packages

    If your tracking shows your order as delivered but you have not received it, please:

    • Check around your property and with neighbors
    • Confirm the shipping address on your order
    • Contact the carrier directly using your tracking number

    If the issue remains unresolved, contact us within 5 business days of the marked delivery date.

    We will work with you and the carrier to investigate the issue.

    Berry Performance Sales is not responsible for packages confirmed as delivered by the carrier or for packages lost or stolen after delivery.

    Refused or Undeliverable Shipments

    Orders refused by the recipient or returned due to an incorrect or undeliverable address are subject to all applicable return shipping charges, restocking fees, and processing fees outlined in our Refund Policy.

    International Shipping

    We ship internationally.

    International orders may require a custom shipping quote prior to purchase.

    To request a quote, contact sales@berryperformancesales.com with:

    • Your country and full delivery address
    • The item(s) you are interested in purchasing

    International customers are responsible for all customs duties, taxes, brokerage fees, import fees, and other charges imposed by their local government.

    These charges are not included in shipping quotes and are non-refundable.

    Questions?

    We're happy to help before, during, or after your purchase.

    Email: sales@berryperformancesales.com

    Berry Performance Sales reserves the right to update this policy at any time. Changes take effect immediately upon posting. It is the customer's responsibility to review the current policy at the time of purchase.

    Return Policy

    Last Updated: June 2026

    We want you to love what you ordered. If something isn't right, here's everything you need to know.

    30-Day Return Window

    You have 30 days from the date your order is shipped to initiate a return. After this window, we are unable to accept returns.

    We do not offer exchanges. All approved returns are refunded according to the terms below.

    How to Initiate a Return

    To request a return, contact us at sales@berryperformancesales.com with your order number and reason for return.

    All returns must be approved by our team before any item is shipped back to us.

    Once your return has been approved, your item must be shipped within 10 calendar days of approval. Valid tracking information must be provided upon request.

    Items shipped without prior approval, without verifiable tracking information upon request, or outside this window may be refused and returned to sender at the customer's expense.

    Return Conditions

    To be eligible for a return, items must be:

    • Unused and in original condition
    • In original packaging
    • Complete with all original parts, hardware, manuals, accessories, and promotional items

    The following items are not eligible for return:

    • Custom-ordered products
    • Programmers and tuners, unless brand new and factory sealed. Any unit that has been connected to a vehicle, registered, or used to flash a tune is not returnable, regardless of packaging condition
    • Open Box listings
    • Installed, modified, painted, coated, welded, cut, or otherwise used products
    • Items marked as Clearance, Closeout, or Final Sale

    Products sold as kits, complete systems, or bundled packages must be returned in their entirety. Partial returns are not accepted.

    Items that include promotional products, discounts, or free gifts must be returned with all included items. If any promotional item is not returned, its retail value may be deducted from the refund.

    We strongly recommend test-fitting all parts before installation, painting, coating, or modification.

    Labor costs, installation fees, tuning expenses, diagnostic charges, rental vehicles, towing fees, downtime, or any other incidental or consequential costs are not reimbursable under any circumstances.

    If you're unsure whether your item qualifies for return, contact us before purchasing.

    Once we receive your return, we will inspect the item before processing any refund. We reserve the right to deny a return or reduce the refund amount if the item is received in a condition that differs from what was originally shipped, including signs of use, missing parts, altered packaging, or damage that occurred after delivery.

    If a return is denied, the item will be shipped back to the customer at the customer's expense. We will attempt to contact the customer to arrange this. Denied returns left unclaimed after 30 days may be disposed of at our discretion.

    Fitment Responsibility

    Vehicle compatibility information is provided as a guide only and may not account for all modifications, trim levels, production changes, or custom applications.

    It is the customer's responsibility to verify fitment before ordering.

    Berry Performance Sales is not responsible for fitment issues resulting from vehicle modifications, engine swaps, aftermarket components, or inaccurate information provided at checkout.

    If you have questions regarding compatibility, please contact us before placing your order.

    Race Use & Off-Road Products

    Some products sold by Berry Performance Sales are intended for race use, off-road use, or closed-course competition only and may not be legal for use on public roads.

    It is the customer's responsibility to verify local, state, and federal regulations before installing or using these products on a street-driven vehicle.

    Berry Performance Sales is not responsible for fines, citations, emissions violations, or other legal consequences resulting from the use of race-only or off-road-only parts.

    Return Packaging Requirements

    Do not write on, tape directly to, or affix shipping labels to the manufacturer's packaging.

    Returned items must be shipped in an outer box or protective packaging sufficient to prevent damage during transit.

    Items returned with damaged, altered, or missing packaging may be subject to additional deductions or denial of the return.

    Customers are responsible for ensuring return packages are properly packed and delivered to us. We strongly recommend using a trackable and insured shipping service.

    Fees to Know Upfront

    We believe in being transparent about costs:

    • Restocking Fee: 20% — deducted from all approved return refunds
    • Return Shipping: Buyer's responsibility on all standard returns
    • Cancellation (Installment/Payment Plan): 7% fee to cover transaction costs
    • Cancellation (Credit Card/PayPal): 3.5% processing fee
    • Cancellation (Backordered Parts): 3.5% fee, regardless of payment method, to cover processing costs already incurred

    Damaged, Defective, or Incorrect Items

    If your order arrives damaged, defective, or incorrect, you must contact us within 48 hours of delivery at sales@berryperformancesales.com.

    Claims reported outside this window may not be eligible for resolution.

    When contacting us, please include:

    • Your order number
    • A description of the issue
    • Clear photos or video of the damage or defect

    Do not install, modify, or use a damaged, defective, or incorrect item. Installation or use of such items constitutes acceptance of the product's condition and may void eligibility for return, replacement, or warranty consideration.

    Items confirmed to be defective due to a manufacturing defect or fulfillment error will have return shipping costs covered by Berry Performance Sales.

    Manufacturer warranties are separate from our return policy and may require inspection, troubleshooting, or approval directly through the manufacturer.

    Refunds

    Once we receive and inspect your return, refunds are processed within 3–5 business days back to your original payment method.

    Original shipping charges, expedited shipping fees, freight charges, customs fees, duties, taxes, brokerage fees, and other non-refundable service costs are not eligible for reimbursement unless the return is the result of a verified fulfillment error by Berry Performance Sales.

    Refunds are issued only to the original payment method used at checkout.

    You'll receive a confirmation email once your refund has been issued.

    Payment Disputes

    If you experience an issue with your order, we ask that you contact us directly before initiating a chargeback or payment dispute.

    Most concerns can be resolved quickly through our customer support team.

    Questions?

    We're happy to help before, during, or after your purchase.

    Email: sales@berryperformancesales.com

    Berry Performance Sales reserves the right to update this policy at any time. Changes take effect immediately upon posting. It is the customer's responsibility to review the current policy at the time of purchase.

    Disclaimer

    All products are sold for off-road use only unless otherwise specified. Buyer assumes all responsibility for installation and operation. Seller is not liable for any incidental, indirect, or consequential damages — including engine failure, labor costs, or vehicle downtime — resulting from the use of any product sold.

    By making a purchase from Berry Performance Sales, you acknowledge and agree to abide by the terms and conditions of these Policies.

    For any questions or concerns, please contact us — we’re always happy to help.

    Recently Viewed