How To Test A Pcm On A Ford?

How To Test A PCM On A Ford?

How often have you or someone you know known how to test a PCM on a ford, for example? Modern automobiles rely heavily on computers to control their systems. Except if you’re an AARP cardholder or an antique automobile collector, the answer is almost always “never”.

Computers manage the timing, air-to-fuel ratio, and even how our automatic transmissions shift. Less upkeep isn’t the only benefit here. As a result, computers can adjust on the fly to account for changes in temperature and humidity.

Is there a con? Computer issues can be difficult to detect. We’ve put together a handy guide for you.

How To Test A Pcm On A Ford?

When Does A PCM Failure Occur?

Most of your car’s operations are controlled by the PCM, which works in conjunction with the ECM and TCM.

Let’s start with some common PCM failure signs.

  1. The “Check Engine” light is on.
  2. Other warning lights besides traction control and ABS may be on.
  3. The loss of fuel economy is sudden.
  4. Starting your car is a chore; it either takes numerous attempts or it never starts.
  5. Idle stuttering or stalling
  6. You can’t always shift because your transmission jerks, skips, or doesn’t shift at all.

Other reasons may cause these symptoms. Poor gas mileage might be caused by a low battery, a defective starter, or under-inflated tires. Check your PCM if you have two or more symptoms with no obvious cause.

How To Test A PCM On A Ford?

How To Test A Pcm On A Ford?

It’s critical to have all of the necessary equipment on hand before beginning any project. For testing a PCM, you’ll need the following:

  • An OBD II or OBD code scanner and a standard flashlight
  • Multimeter
  • A brand new PCM has been released (if replacing)

A Visual Inspection Is The First Step

Rust or a broken wire are the first things you should look for before beginning any car repairs. While this isn’t the most common reason for a PCM to fail, it’s the quickest and easiest to fix.

There should be no rust on the battery cables or the PCM itself if you want your battery to function properly. If required, tighten down any exposed cables. If your PCM has been corroded, you’ll need to go straight to step 5.

Inspect Your Battery

Keep an eye on your battery’s charge while you’re using your multimeter to check the voltage. When the engine is off, the voltage should be at least 12.6, and it should be 13.7 volts when the engine is running.

If it’s less than that, check to see if the battery is fully charged. Your PCM won’t be able to get the input it needs to make the correct changes if certain sensors fail due to low voltage exposure.

Code Scanning

OBD code scanners can be used to check the PCM for any OBD error codes if your battery is completely charged and there are no signs of rust on it. You can use these codes to narrow down which electrical and mechanical systems are causing the problem. This can be quite helpful in solving many electrical and mechanical problems.

You’ll need to know what the codes signify to understand them, therefore a codebook (or simple Google access) is a must.

Several PCM-related error codes, such as P0113, P0603, P0606, and U0100, have been discussed previously. Error codes that are most frequently displayed are included in this list, which is not comprehensive.

Check Sensors And Wiring

How To Test A Pcm On A Ford?

Things can get hard at this point if the preceding phase didn’t go well. You need to inspect the sensors and wires that are linked to your PCM. If you observe one, two, or three PCM codes, it can assist you to pinpoint the specific sensors or wires that are malfunctioning.

These cables should be inspected visually and electrically with a multimeter. Ground wires and connection points are common sources of malfunction, so be sure to inspect them thoroughly.

Reset your car’s codes once you’ve replaced any defective components and drive for a while. You’re likely to have figured out the issue.

Install A Replacement

As a last resort, or to confirm some repairs, you may require a replacement PCM. Make sure that the PCM is compatible with your model and year, not only with the make and model. Improved performance will be noticeable as soon as the PCM is fixed.

You’ve just learned how to put a PCM to the test, folks.

What Should I Do If My PCM Needs To Be Replaced?

If, after completing the above instructions, you discover that your PCM needs to be fixed or replaced, you should seek the assistance of a qualified mechanic. Repairing or replacing your PCM yourself is doable, but it necessitates the use of specialist tools you may only need to use once.

How Do I Know If My Ford PCM Is Bad?

There are a few signs that your Ford PCM may be bad, including decreased performance or engine power, trouble starting the car, or difficulties with shifting gears. Other possible indicators include error codes displayed on the vehicle’s dashboard and decreased fuel efficiency.

If you suspect that your PCM is malfunctioning, it is recommended that you have it tested by a professional mechanic.

How Do I Test A PCM?

There are several different ways to test a PCM, including using an OBD code scanner, checking the battery voltage, and inspecting the battery cables for corrosion or damage. You may also want to check any associated sensors or wiring as part of your testing process.

To confirm that your PCM is functioning properly, you can reset any codes that appear and then drive your car for a while to see if any new codes appear. If you are still experiencing issues, it may be necessary to replace your PCM altogether.

What Is A PCM Self-Test?

How To Test A Pcm On A Ford?

A PCM self-test is a process that you can use to test the functionality of your PCM without having to take your car to a mechanic. This can help diagnose issues with your vehicle and may save you time and money in the long run.

To perform a PCM self-test, you will need to connect an OBD code scanner to your car and then turn on the ignition. Once the scanner is connected, it will run a series of tests on the various systems in your car. The results of these tests will help you determine if there are any issues with your PCM.


Testing a PCM is an important step in diagnosing and fixing many types of electrical issues with your car. To properly test a PCM, you will need to use a multimeter, code scanner, flashlight, and other tools depending on the specific issue you are trying to troubleshoot.

You should also inspect your battery for rust or corrosion, as well as any worn or damaged wires and sensors. If your PCM is defective and needs to be replaced, you should seek the help of a qualified mechanic to complete the repair. With these steps, you can effectively test your PCM and get your car back up and running in no time!


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