AutoECMs Blog — ecm repairs


What is an ECU - Electronic Control Module?

What is an ECU?

An Engine Control Module or Electronic Control Module (ECU) acts as the brain for your car. In fact some people call it the brain box.

ECUs are generally used to monitor and control engine functions such as determining what position the gas pedal is at while idling. This allows the car to know that when you step on the accelerator how much gas it needs to feed the engine based on the amount of throttle you’re giving it.

ECUs also control transmissions, telling the car when to switch gears while driving an automatic transmission vehicle. It can adjust the gear ratio depending on what setting it is put in - such as reverse, drive, overdrive, or sport. 

And some ECUs (known as Body Control Modules) control the function of the windows, door locks, and sunroof - basically all the accessories in or on your vehicle.

Before manufacturers switched to using engine control modules and a large network of computers to control the vehicles functions, everything was manual. Typically the only non-mechanical item in an older vehicle was the radio. Windows, door locks, and all the basic functions drivers now expect in their vehicles were manually operated. 

One of the primary functions of an ECU is monitoring a series of a cars actions to register errors with how it is operating. If an error is detected the ECU will generate a trouble code.

Once the ECU notices the problem and generates the trouble code, it will cause the check engine light to come on. When you notice that your check engine light is on, you should take your car in to have it examined by a mechanic.

The mechanic will hook your car up to an OBD scan tool like the Autel MaxiScan MS300 CAN Diagnostic Scan Tool for OBDII Vehicles and will register any OBD error codes that it may be sending. At this point the mechanic will inspect the location of the error and advise you of any ECU repairs necessary.

Unfortunately if your ECU is malfunctioning you may need to have the ECU repaired or replaced. If your ECU is damaged or the motherboard is corroded you will need a total replacement. Corroded or burned ECUs are generally not repairable.

ECU’s are integral to the operation of modern cars. These are not simple mechanical devices that you should attempt to repair on your own. Make sure that if you are experiencing any problems with your ECU you take it in to a mechanic as soon as possible.

The average cost for a brand new ECU from the original manufacturer runs around $1,500 per unit. Refurbished ECUs like the ones sells can cost a lot less and are a suitable replacement for your defective ECU.

AutoECMs has an extensive database of part numbers for most makes and models of cars/trucks/vans and more. The best way to confirm you are getting a suitable part is to pull the defective ECU from your vehicle to confirm the part number your specific automobile requires.

To learn more about ECUs, here are some good links that will explain the components of an engine's computer network.

Feel free to give us a call if you have any questions about your specific part or need to know availability and pricing. 1-800-900-0194 


DPC-402 Hardware Code Ford Engine Computers

The DPC-402 P/N is a hardware code for the PCM in a Ford truck or van. There are multiple engineering numbers associated with the DPC-402 hardware code.  

If you are looking for DPC-402 Ford PCM’s give us a call at AutoECMs to find out if we have the engine computer you need in stock.

AutoECMS sells remanufactured engine computers and can get you the part you need to get your FORD vehicle back on the road this week.

As much as we love talking to our customers on the phone, we are always super happy when you purchase a part on our webstore directly. We LOOOVE web orders!

If you place a web order you will receive an email from us saying we got your order... and we will send you a tracking number and receipt for your records to the email address you provide when you place the order. If you have any questions about your order, please don't hesitate to call or email us!

We process orders Monday through Friday between 8:30AM to 6PM. Orders which are received on the weekend will be processed the next business day.

Call AutoECMs anytime at 1-800-900-0194 for more information about FORD DPC-402 parts or to check availability and stock levels.


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The Engine Computer Isn't the Problem. What Now?

You took your car into the shop because your check engine light was on. After running the On Board Diagnostics (OBD) the auto tech advises that the problem is with your engine computer. He recommends that you purchase a replacement module to correct the problem. After replacing your old part with the new one, the same OBD code shows up.

What do you do if the engine computer is not the issue?

First of all, don't blame the auto tech. He's probably a good guy! He ran the OBD scanner and got back a legitimate code. This happens sometimes. It's not a common problem with ECM repairs, but we do see this happen on average several times a month.

If the ECM replacement doesn't correct the original problem, it's important to see if the issue is somewhere else in the automobile. Perhaps the diagnostics gave a code which made it look like the ECU was defective. This may seem like a mistake on the part of the auto tech, but it's actually good to know that the same issue came up when the replacement was inserted.

By showing the same code, you will know that the problem isn't with the computer.

There are a couple of things to keep in mind at this point:

1) If the computer had the exact same problem, take a good look at other areas of the engine and wiring, etc. It could be something elsewhere that isn't so apparent.

2) Also, ensure that the part number ordered is an exact match or a verified interchange with the part pulled from your car. The interchange will not affect the functionality of the car, and because the same code came up when you inserted the interchange it's definitely not a problem with the interchange.

What now? You're probably thinking you're stuck with the part. If you bought a part from us and there is a misdiagnosis at the repair shop, we accept returns and will issue a refund less a $75 restocking fee.

We always hope that the engine computer is the problem with your car repair so you can get back on the road faster, but in case it's not - we understand. Give us a call if you encounter this issue. We're happy to help. 

If you have any questions about Auto ECMs return policy, feel free to contact us at 800.900.0194.