ONLINE STORE Auto Computer Pro - TRN Electronics Specializes in Diesel ECM PCM Electronic Controllers for Heavy Duty Big Rigs. We also Service many US Domestic & Japanese MFD Cars, Light and Medium Truck Engine Computers and Electronic Controllers



You need good reliable information before you make a huge purchase like an ECM or PCM Engine Control Module or Controller. Auto Computer Pro – TRON Computers TRN Electronics is at your service and will get you all the facts and help you need. We have been Testing, Repairing, Programming and Reselling Engine and Transmission and other Electronic Controllers ECM MCM PCM TCM BCM in the Houston and surrounding areas and online at since 1997. Our goal is to help your shop maintain its quality and service to their customers by providing the best source for ECM MCM PCM CPC4 FICM TCM Electronic Controller Module OFF-RIG OFF-VEHICLE TESTING, REPAIR SERVICE, PROGRAMMING, CLONING AND EXCHANGE SALES.

In partnership with TRON Computers, together we specialize in Diesel ECM MCM FICM for Heavy Duty Rigs and tractors and Industrial Electronic Computer Controllers. We also specialize in Medium duty Diesel by Ford, Dodge Cummins, GM Duramax, Allison TCMs and others. We are located in the northside area of Houston. We have a lab to test off-vehicle Detroit Diesel DDEC DD13 DD15 CPC4 CAT C5 C7 C11 C13 C15 C17 C23 C25 C27 70 pin Cummins CELECT and CELECT PLUS L10 M11 N14 ISB ISM John Deer ECM Skid Steer Modules Dodge RAM Cummins ISB ISM 5.9l 6.7l Ford Powerstroke ECM IDM GEM 7.3l 6.7l PCM and many more. We also service Light and Medium Duty vehicles and Legacy ECM PCM ECU TCM DPC IDM FICM Cloning & Replacement Modules. See more in our HEAVY DUTY ECM PAGE. We also specialize in LEGACY VEHICLE ECM SERVICES. See more on our LEGACY ECM PAGE.

LEGACY YEARS MODELS SERVICING: / Auto Computer Pro specializes in OBD-I (1988-95) & OBD-II (1996-2014) OEM Repair Service & Replacement ECM and PCM Engine, Transmission and Electronic Control Computers, including ECM PCM Verification Testing Services, ECM PCM Repair Services, and OEM and custom PCM Programming services. We specialize in CHRYSLER, DODGE, JEEP, RAM, FORD, LINCOLN and GM and JDM. We do not offer servicing of some Japanese vehicles and no European products. Please contact us with your year make and model and we can let you know if we can service your model.

With over 2 Decades of National and International ECU ECM PCM Service & Supply, ECM To Go ensures our customers receive the highest in quality of service and product and the latest technology available. Our founding member has been a leader in this industry since 1997. Our Lead Engineer was not just any technician, but the mastermind behind Off-Board Programming and Plug & Play software and hardware. Unlike our competitors, we offer TRUE Plug & Drive computers when available. We strive to make sure that no additional programming procedures or equipment should be needed. This of course is not always the case due to some very few instances when the manufacturer requires ON-BOARD programming or advanced calibrations.

Please call for details and we can assist you in determining what service will better serve your time and budgetary constraints based on your year make and model and specific symptoms and diagnostics history.

OEM REPLACEMENT COMPUTERS: We offer Jeep, Dodge, Ram, Chrysler, Ford and GM models Replacement ECM PCM computers ready to “PLUG & PLAY”. We have been servicing Auto Dealerships and Repair Service Centers and Do-It-yourselfers since 1997. Our Products include a one year warranty warranty limited to our work or product. All our ECM PCM have all the necessary manufacturers authorized programming including all the updates issued since the production date when available. Call right away for one of our service consultants to help you determine the service best suited for you.

REPAIR SERVICE: Interested in our Repair Services? We offer test and repair services on most Chrysler Dodge Jeep and Ford model engine computer / electronic control modules and still specialize in Mitsubishi DSM. Please call with your year make and model for more information. We always recommend you consult with a certified technician to get all the diagnostic data. We require that the unit be sent with all the diagnostic and drivability problems for our technician to better and quickly find the problem and get it repaired as soon as possible.

WE HAVE HARD TO FIND 2005-06 JEEP WRANGLER PCMs READY TO SHIP! Call right now for more information. You can also go to our Online Store. Be sure to see our Blog related to the PCM Failure issues and vital technical bulletins related to the Auto Transmission shifting issues triggered by a failing PCM.

Please click on the “ON LINE STORE” Link and you can take advantage of our discount pricing and best in the industry Repair Service or may instead offer a Replacement Service to solve your specific needs.


All our products, Electronic Control Computer Repair Service, or our Replacement Computers, are repaired or rebuilt to OEM or better standards. We don’t do anything half way! Once our techs are done with complete repair and reflow, the Computers are thoroughly tested in our State of the Art Testing equipment which verifies all functionality and the success of our work before its return. We include a 1 year warranty with all our products. We have had this same warranty since 1996! If you have an issue with your vehicle, it must be resolved before reinstalling. Any time a coil failure is involved you must check TSB (Technical Service Bulletin) to ensure all required servicing is done. Often only OEM replacement components are required to ensure no further adverse events can occur. We do not warranty our product that is damaged in installation or when it is damaged by preexisting problems not being corrected. We can and often do send back a list of components and/or systems (charging, ignition, power etc) to check before reinstallation of the repaired or replacement Computer or module(s). All diagnostics and repairs or installations require ASE or equivalent service technicians to ensure the vehicle is brought back to OEM.


The automotive computer or engine management system computer has many functions and many uses. Also called an electronic control module – ECM, electronic control unit – ECU, or powertrain control module, PCM. The primary functions are twofold. They act as an engine management computer and electronic and fuel control system for engine and transmission and body controllers, and also they are the main engine on-board diagnostic (OBD) system. Most OBD-II (1996-present) computers in cars are now equipped with the greatest technology available. At the factory, they must be flashed or programmed to fit the specific requirements of the make and model and application. You can no longer acquire a used unit and install it into the vehicle. Once an engine control computer or most electronic control modules are replaced, they MUST be reprogrammed to the application as specified by the VIN (vehicle identification) number and in many cases there are several software updates issued by the manufacturer. This important information is vital to your vehicle running properly.

Engineers manufactured Electronic Control Modules ECM PCM ECU’s with great design and precision. One problem has been revealed over the years: some of the components that were used have shown a tendency to fail, especially by heat. The heat from the normal operation of the current in the unit and the heat from the environment the ECM unit is stored in. Some models are stored in the cab which can reach temperatures of up to 190f. Some models are stored in the engine compartment which is the worst possible environment for a computer processor. The engine compartment is exposed to the elements of the environment outside and the engines operating environment. Normal operations can adversely affect the ECM unit over time as well. Other ancillary components such as actuators like the IAC (idle control motor), ISC, TPS, coil failure, engine sensors, alternator or failing batteries can adversely affect the electronic control unit. Reversing polarity when jump starting vehicle can damage the ECM. The supply of ECMs new and used has been greatly reduced due to the growing competitiveness of this industry. Keep in mind most of these quote-unquote “Rebuilders” are more than likely people that have seen the trend in ECM failures and are trying to capitalize. I’m all for free enterprise — after all, this is America and may God Bless her (and all of us for that matter) but don’t let yourself be fooled by the new kids on the block. Nor should you be misled by the low prices of some of these folks. If it sounds too good to be true and too cheap to be quality, it probably is. You know you can’t wager your safety or that of your family or customers to the opportunity of a “great deal”. Check references! A lot of these guys offering warranties and advertising themselves as rebuilders have not been in business long enough to match the warranty they are offering!

ECM To Go – Auto Computer Supply has been online since 1997 servicing dealerships repair service centers and even do-it-yourselfers. We are the first independent company to specialize in repair service and supply of engine control modules. Our team is second to none in service and quality. Many other suppliers are only reselling used units. Be aware of the used units often sold in salvage yards.



Many people are surprised to find out they have a computer in their car! Many newer models may have more than 10 independent and cooperative computer controller devices aiding in the performance, comfort and environmental factors. They are even more astounded when they find out that the cost is anywhere from $650 to $2000 for a new unit from the dealership! To understand the ECM we can help by a short history of the ECM and implementation of computer controlled electronic systems. The Federal Government implemented the use of computer controlled ignition and fuel systems for 3 main reasons:

  1. To aid in the safety of the consumer
  2. To better economize the fuel consumption
  3. To reduce the output of EPA regulated byproducts of the ignition controlled internal combustion gas/diesel fueled engines in passenger and commercial vehicles

Often when your computer is failing there is misdiagnosis and people will spend hundreds I’ve even seen customers who have unfortunately paid over a $1000 on their car on repairs and part replacement before he finally got to us and he found out he needed only an ECM to solve his problem. I have seen people go without their vehicles for months because the mechanic could not find out he had a computer failure. On the other hand there have been countless others who have paid this amount and more on new computer ECU(s) and the problem does not go away! The key is proper diagnosis! My father always said measure twice cut once. So we are firm believers in getting a second opinion or third if necessary to collaborate repair diagnosis that can be financially crippling.

Most common misdiagnosed parts are battery, distributor, ISC motor, TPS switch, injectors & intake cam sensor, and other sensors or bus system . If the technician does not figure it is the ECM they may sell you parts you may not need.

When diagnosing an EFI or electronic fuel injection system vehicle, here are the “inside” industry approach procedures to engine computer, or otherwise diagnosing a malfunctioning vehicle. These systems all require the same basic elements, and by checking all individually, you may be able to rule out and systematically diagnose your problem and save hundreds of dollars.


Is your car starting and running, but stalls or seems to not idle right.

  • If so, is the check engine light illuminated MIL or (malfunction indicator lamp) on intermittent or all the time?
  • If so, what are the MIL DTC diagnosis codes? Try pulling ECM and looking and smelling for burns. Have your ECM tested to be sure it is functioning properly. If the ECM is bad, have it repaired or replaced with known remand or new unit. see
  • If ECM is OK, then follow the error codes it gives, and check the appropriate malfunction (i.e.: check engine light coded you had bad oxygen sensor, try unplugging it and restarting car to see if any change in running or the MIL. If no change, try putting a known good used unit in, or buy new unit if in your budget.)
  • Have ECM scanned in car by authorized tech with proper scan tools specific to application (only after installing or verifying you have a good ECM). Most manufactures have specific tools to their equipment even though there are many scan tools that can do basic diagnosis. This scan should show what elements are giving you the problems. There are some ways to check error codes without scan tool. Refer to manual for key to specific application.
  • This insider tip is for Mitsubishi & Chrysler Vehicles and is quite helpful for diagnosing or testing your ECM. You need an analog volt/ohmmeter, put the testers on pin 1 and pin 12 (top right & bottom left pin) of diagnosis ECM scan cable harness. This harness is inside the cab area, usually in driver´s side upper left of drivers kick panel. The sweeping motion left to right means ECM is OK. Sweep right to left means reverse testers to pin 12 and pin 1. A movement to the right without bounce or return means bad ECM.
  • Many models also have ways to check the MIL codes an indicator light on the dash or ecm or will illuminate the check engine light in series indicating the first digit then the second digit will follow and the indicators will repeat.

Your car Is not starting? As we started earlier, all efi engines need the basic elements to run:

  1. Battery power send voltage to starter to crank over the engine, and voltage references to and from ECM computer and supply power to relative components for vehicle operation
  2. Starter/solenoid
  3. Injector pulse- voltage reference from ecm to injector(s)
  4. Fuel (ecm sends voltage reference often via mpi relay to fuel pump)
  5. Spark to spark plugs to ignite the fuel/oxygen mixture for usable power

Knowing this you can then systematically check these separately…..

  • Power- battery/alternator system:
    1. If you have lights, you may be OK for cranking. But if she’s sat up for a while, you may want to have a battery charger or power/booster charger available and attached to your battery with a good grounded connection.
    2. If no lights check battery voltage with multi-meter. If less than 12 volts check alternator.
    3. If alternator bad replace, else replace battery.
    4. If you hear clicking and have power, check starter/solenoid. (Try tapping on the starter with a wrench a couple times. This sometime can be a temporary fix to free up the locked solenoid which often locks and won’t engage. Replace Starter or solenoid with known good remand or OEM model..
  • Injector pulse: Put a node light or meter on injector #1 to see that the ECM is sending injector pulse. If not pull ECM and look and smell for burns.
  • Spark to plugs: Check for spark at plugs, check the following if applies to your vehicle: distributor (coil, igniter, crank angle sensor, cam sensor), relay, ecu
  • Fuel/fuel pump reference
    1. Check voltage reference from ECM or from mpi relay to fuel pump. You can often hear it kick in. You can also see the flow from pump to ensure it is solid. Be sure to do this in controlled environment! IF fuel pressure is normal, it will shoot across the room! Have a volatile fuel receptacle ready like a larger glass jar or gas can
    2. If you have no voltage reference to fuel pump, check relay. If relay OK, check ECM for burns or smells. Test ECM.
    3. If reference to fuel pump but no fuel pressure, check fuel pump.




FOR CUMMINS CELECT tm & CELECT PLUS tm only N-14 M-11 L-10 Equipped Engines

ECM TO GO Auto Computer Pro is one of the most reputable names in auto and heavy duty Electronic Control Module (ECM) repair and supply:

  • The ECM is the power control module for heavy duty engines and or power control module for your trucking industry tractor engines and automatic transmission control computers for Buses, Coaches and Fire Trucks & heavy machinery electronic controllers. We have been repairing ECMs since 1997. We offer testing and repair service and can supply many models remanufactured in advance for inventory sale for minimum lost production time. Our automotive ECM division began research and development on heavy duty ECMs in 1999 due to the high demand and high failure of Cummins, Detroit D-DEC, Allison and several other manufacturers. We understand that heavy duty transportation rigs and mechanical equipment is vital to the running of a business big and small and even vital to the running of basic commerce. Even more so we understand that without your delivery services operating, you are not only losing money, it may even cost you many more dollars in production, leasing fees or lost jobs and revenue. Presently when you are faced with a bad ECM your only options are purchasing a new unit from the manufacturer which can cost from $2,500-$5,000 US to using a “pullout” or used ECM which is unlikely to be still in working order and would have to be reconditioned and coded with the features and parameters of the tractor truck or rig. This used unit option does not give you specific data to help your service department locate a problem that has adversely affected the ECM and may likely reoccur and damage the unit again.
  • We have found that many models of the engine and transmission and other electronic controllers for heavy duty trucks and heavy duty machinery, often called ECMs, are exposed to many factors that damage the internal electronics of the ECM. Factors adversely affecting the electronic controllers are normal operation such as powering up or down, engine idle sensors, failed injector(s) in diesel engine, fuel solenoid operation, and even lightning strikes. Also due to the location of many of the ECM units, often they are mounted to the engine and exposed to the environment; simple maintenance operations such as power washing the rig can be detrimental to the ECM’s and the wiring harness.
  • We have researched and confirmed many model ECMs fail after 3 to 5 years of use due to the failure of internal components on your ECM simply failing due to electrical spikes and the aforementioned events. These components must be replaced in all remanufactured ECMs in order for your computer controller board to function properly. We offer an ECM testing service on-rig for many makes and models. Your ECM could also have taken an electrical hit from a bad injector(s), the engine idle sensor or fuel solenoid, and/or a compromised actuator harness. We can instruct you on which components may have damaged the ECM when we test the ECM on site at our facility. By looking at the damage on the ECM motherboards, often we can detect specific vital information to ensure you do not damage another expensive replacement ECM computer. After the ECM repair is complete, memory features and parameters are restored to the ECM. We reprogram your ECM to your engines specifications including your governor settings, rpm settings, Jake brake, cruise control, tire size, rear axle ratio and more.
  • All our units include a 1-Year unlimited mileage limited warranty*. We include a warranty checklist which accompanies all outgoing repaired and programmed ECM units to finalize the repair of the truck before ECM installation. ECMs and electronic controllers now have many different applications and many are programmable. The features and parameters are coded into the ECM by the manufacturer and we are an authorized programmer for most heavy duty mfd ECMs and electronic controllers. The features and parameters are often referred to as a CPL or Control Parts List number which we can apply to each outgoing unit. We offer some models that can be purchased in advance that are remanufactured with upgraded components and we can program the ECM to your rig in advance. Or take advantage of our experienced technical team in a support role. We only ask for the opportunity to service your heavy duty trucks and equipment. Our main goal is to supply quality service and products at an affordable price.


Info provided by John B. South

  • Corrosion and moisture: Corrosion or damage due to moisture is one of the main reasons for ECM failure. Corrosion can enter the ECM through the wiring harness and moisture can enter by a failure in the seals in the ECM itself. This happens over a period of time (5 to 10 years) due to the ECMs exposure to the elements.
  • Fuel solenoid: The electronic fuel solenoid is also a main reason for failure in the ECM. The solenoid can cause a short in the ECM due to corrosion in the solenoid or the wire running from the solenoid to the ECM harness. The electronic fuel solenoid is located at the top of the fuel pump. The solenoid seems to fail due to corrosion as fast or faster then the ECM. If your truck is running fine then you shut your engine off and it won’t restart then this is a good indication that the starter has shorted out the ECM.
  • Injector wiring harness: The third thing that can cause failure in the ECM is the Injector wiring harness or the sensor wiring harness. Once again corrosion or breaks in the internal wiring in the harness can cause a short in the ECM or corrosion can enter the ECM through the wiring harness. Again this is caused by exposure to the elements
  • Grounding issues: Another issue that can cause failure in the ECM is poor grounding. This can be the result of loose or corroded ground wires to the battery or the frame. This is especially problematic in the Celect Plus model.
  • Starters: Replacing the starter with the wrong model starter is becoming a big problem with the Celect Plus ECMs. Many starter rebuilders will bypass the override sensor in the starter. The override sensor regulates the voltage going to the ECM so when the override sensor is bypassed you will get voltage problems in the ECM and it can generate fault codes or other problems. If you only started having problems with your ECM after installing a starter then the starter is most likely the root of your problem.
  • Dead battery cells: Dead cells in batteries can cause failure in the ECM. Many times a battery is left in the rig long after a cell has died. This affects the grounding in the battery.
  • Jump start: If the vehicle has been jump started recently and the cables were connected improperly this can cause a spike in your ECM and cause it to short out. A bad jump can also blow out 2 amps which are located between the ECM and the firewall.
  • Welding and lightning: Arc welding on the frame can blow out the ECM as well as lightning strikes. This is not very common but it does happen from time to time.
  • Identifying the problem: If your check engine light is on then you should be able to read a fault code from your ECM. The fault codes should help identify where the problem is originating from. You can also check the voltage where the wires come into the ECM harness with a voltmeter. The voltage should be between 9 to 12 volts for optimal usage. Anything 6 or below and you have a problem.