Home The Long Haul Blog Why You Should Request An Ecm Report When Buying A Used Commercial Truck

Why You Should Request an ECM Report When Buying a Used Commercial Truck

April 24, 2023 Truck Sales Author: Rush Truck Centers Read Time: 4 Min

Information provided by Doug Shields

We are excited to introduce a brand-new series of articles that promise to answer many of the questions that a prospective commercial truck owner might have when considering a used truck purchase. The articles in this multi-part series will come from industry experts with real-world advice on exactly what to look for, and what to avoid when buying a used truck. We’ll dive deeper into topics related to vehicle class, the trade-in process, pre-certification, warranties, and more. Just straight facts and no fluff to help you make a solid, fact-based decision when buying your next commercial vehicle.

As a truck buyer, knowing what you’re getting for your money when investing in a commercial used truck is important for the future success of your business. You want to ensure the truck you’re driving or adding to your fleet is road-worthy and doesn’t have underlying issues that could prove costly or even dangerous down the road.

Fortunately, technology has come a long way and brought with it some major advantages. The engine control module, commonly referred to as the ECM, found in all commercial trucks can provide you with a considerable amount of information about what’s going on under the hood. From details about the engine to the truck’s driving history and any previous issues under its previous owner, the ECM holds a lot of valuable data that can be crucial to have in hand during the truck buying process. That's why we broke down the top reasons why you should always ask for an ECM report when buying a used commercial truck.

What Is an Engine Control Module (ECM)?

You might have heard the term ECM, but you might not be entirely familiar with what it is or what it can offer you as a prospective truck owner. Logically, the engine control module (also referred to as a powertrain control module or PCM) controls the engine and powertrain. What you may not know, however, is that it also tracks many of the events specific to the engine.

The engine control module is attached to the side of the engine and functions much like its “brain,” controlling the air-to-fuel ratio, ignition timing, variable cam timing and emissions control. The ECM also regulates the fuel pump, engine cooling fan, and charging system and constantly monitors emissions via onboard diagnostics. The transmission controller, anti-lock braking system (ABS)/traction/stability control system, body control module, climate control module and anti-theft system also interact with the ECM during operation. On top of all that, the ECM monitors the engine for any potential problems, records diagnostic fault codes, and is responsible for turning on the check engine light when an issue arises.

Because the ECM interacts with and controls so many components of the powertrain, it receives a multitude of data points on engine performance and any present issues. This data is accumulated in a detailed downloadable report that provides a clear picture of the engine’s operations for technicians and prospective buyers.

8 Reasons to Request an ECM Report for a Used Truck

Given the engine is the most expensive component on any commercial truck, it is in your best interest to request a copy of the ECM report and have a trusted technician review it with you before you make a purchase. Here are the top eight things the ECM can provide:

  1. An ECM Report gives you a snapshot, in time, of the engine and any issues it might be experiencing in the form of active fault codes. It also provides a history of engine and related component events that can be used to identify trends and pinpoint the origin of any problems.
  1. An ECM Report allows you to calculate the overall fuel efficiency of the truck by providing you with total miles (engine miles) and total fuel consumed.
  1. An ECM Report gives you the total hours on the engine versus what’s showing on the odometer.
  1. An ECM Report tells you how much idle time the engine has experienced and how much fuel was used. This helps you accurately calculate the true miles per gallon.
  1. An ECM Report will give you the true horsepower of the engine.
  1. An ECM Report will tell you the maximum road speed and if the truck is governed. Governors are often used on large trucks to limit their top speed and increase fuel efficiency.
  1. An ECM Report will tell you what features of the engine, such as idle shutdown, are enabled or have been disabled by the previous owner.
  1. An ECM Report helps you ensure that you’re buying a quality truck and not one that will be ripe with issues and needed repairs later.

Rush Truck Centers Make-Ready Process for Used Trucks

Every used truck Rush Truck Centers sells goes through a rigorous make-ready process that includes a 21-point reconditioning process and a passed federal DOT inspection. We also verify the emissions system is present and working within factory specifications, perform a preventive maintenance service, and professionally clean and detail our trucks prior to sale.

And we always download a full ECM report and address any issues found as well as verify the engine and odometer miles. Our truck sales experts and technicians would be happy to review the ECM report with you for any used truck you’re looking to purchase to make sure you fully understand the condition of the vehicle.

Contact or visit one of our more than 140 dealership locations across the U.S. to find a used commercial truck that fits your needs.

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About the Author

Doug Shields

Doug has been a mainstay in the new and used heavy-duty truck industry for more than 25 years. Formerly Rush Enterprises' Director of Used Truck Operations, Doug serves on a number of industry and OEM committees and councils and has written countless sales and management-related articles specific to our industry that have been published in the Used Truck Association monthly magazine. Retiring in 2024, Doug enjoys playing chess and poker and spending time with his family in Arizona.