7 most common PCM Failure on 7.3 Powerstroke (easy solutions)

When the 7.3 Powerstroke PCM fails, symptoms such as engine stalls, transmission issues, poor performance, and high emissions occur. Caused by power surges, water, high temperatures, and faulty circuits. And PCM failure can be fixed by software updates, circuit re-wiring, or replacement.

The signs of PCM failure include;

  • engine stalling, ignition problems
  • fuel guzzling
  • bad performance.

Since the PCM controls the transmission, gear shifting becomes difficult and random. Module failure also activates the check engine light and displays error codes.

The failure can be quite problematic. It is vital to learn to read the signs of impending module failure to avoid catastrophic failure while out in the middle of nowhere.

Here are the 7.3 Powerstroke PCM failure symptoms, its causes, how to fix it, and how much repairs cost, drawn from my experience.

7 most common PCM Failure on 7.3 Powerstroke

When damage occurs, trouble codes are one of several bad PCM symptoms. Some codes, like p1249 code 7.3 Powerstroke, which I have explained in another article, show few signs. However, there are numerous signs of PCM failure since the module controls many processes.

1. Difficulty starting

If you have problems starting your car, the issue may be a failing PCM. A faulty PCM can mistime the sparks from the spark plugs, causing ignition problems by failing to ignite the air-fuel mixture.

2. Gear shifting issues

The PCM controls both the engine and automatic transmission. If the module gets damaged, you will notice that it gets harder to shift gears, leading to poor handling.

Another sign of PCM is random gear shifting. The car will randomly shift to unchosen gears or get stuck in one, and eventually, the transmission fails completely.

3. Fuel guzzling

PCM failure affects the transmission and makes gear shifting unpredictable. Transmission efficiency affects fuel economy directly, and if the car’s gears don’t handle correctly, it becomes a fuel guzzler.

4. Error codes

Many engine issues can activate the check engine light on the dashboard, including PCM failure. PCM failure also prompts the display of trouble codes. When the check engine light on, but there’s no error code, diagnose the engine first. If there are no issues, then the PCM is the problem.

5. Sub-optimal engine performance

The PCM controls the engine, so any failure results in a noticeable drop in performance. Mild PCM damage will only cause problems in specific situations like acceleration, while significant damage can render the car undrivable.

6. Stalling

Engine stalling can indicate that the PCM is failing. Since the module controls processes such as engine timing, if it malfunctions, the engine will misfire, causing stalls. Some of these failures occur in specific conditions leading to a car that works perfectly in most cases but is unreliable.

7. Unusually high emissions

This symptom is hard to notice unless you conduct an emission test on your car. If your vehicle fails the emissions test, the problem could be the PCM. The PCM regulates the air-fuel mixture, and if it has too much air or fuel, incomplete combustion occurs, causing more emissions.

Sometimes high emissions are caused by a faulty fuel pump. In this case, the p1211 code 7.3 Powerstroke, which I have written about in a separate article, will appear.

What Causes 7.3 Powerstroke PCM Failure?

PCMs are some of the hardiest car components, so the problem is mostly software-related when they fail. Other causes of PCM failure include;

  • Water damage – water destroys electrical components and connections.
  • Extreme temperatures and vibrations – cause stress and interfere with the operation of the PCM and sensors.
  • Malfunctioning charging systems
  • Power surges – the module cannot function if the voltage is too low while high voltages fry it.
  • Short circuited components
  • Corrosion of power circuits

How Serious Is The 7.3 Powerstroke PCM Failure?

The PCM controls a car’s engine and transmission. Hence, any failure, no matter how small, causes issues like rough handling and poor fuel use. Eventually, when the PCM is too damaged, the car won’t even start or run.

Fortunately, in most cases, PCM failure can be solved quite easily by software updates or some minor fix. There are only a few cases where you must replace the PCM.

What To Do When 7.3 Powerstroke PCM Failure Symptoms Appear?

PCM failure symptoms can be due to unrelated module problems, so you should diagnose to be sure. The most common 7.3 Powerstroke PCM location is the driverside firewall, under the brake master, by the fender. 

Troubleshooting guide

To perform a successful PCM diagnosis, you need the following tools.

  • OBD scanner
  • Multimeter
  • Screwdriver
  • Flashlight

Step 1: Voltage measurement

Before you begin troubleshooting, measure the voltage across the battery. If the car is running, the reading should be 13.7 volts, and if the engine’s off, 12.6 volts. Any lower voltages show that you need to charge the battery.

Step 2: Circuit Inspection

First, perform a visual inspection on all the wires to ensure that none are corroded, rusted, or loosely connected. Disconnect the PCM, and use the multimeter to test that all the wires work correctly. If all the wires are okay, test the circuit components’ grounding.

Step 3: Perform a scan

If the battery and wiring are good, scan the PCM and see whether there are error codes. Get an error code manual and determine if any error codes displayed are related to the PCM. If there are no error codes, then the issue may not be the PCM.

Step 4: Check the sensors

The error code will guide you on what sensors and circuits to troubleshoot. Check for loose wiring, corroded wires, or damaged sensors that may break the circuit and lead to no communication with PCM.

Once you fix or replace any damaged parts, reset the codes, and then rescan to see if the problem is resolved. If the problem persists after all these steps, then I suggest replacing the PCM.

How to Diagnose a Module Failure | Ford Tech Talk >> Check out the video below:

How Much Does It Cost To Deal With 7.3 Powerstroke PCM Failure?

Typical PCM costs between $500 and $1,500 depending on the car model and age. If you have to replace the module, find a mechanic to help you. Labor costs about $100 on average.

In most cases, software updates and reprogramming solve PCM failure. However, you can’t update a module without the right software, so you must go to a qualified dealership or mechanic, which costs between $50 and $150.

people also ask (FAQs)

Here are answers to some of the most common PCM-related questions.

1. Are PCMs interchangeable between cars?

PCM modules work with specific drivetrains by design, so they are not interchangeable between car models. Before you do a 7.3 Powerstroke PCM replacement, ensure the year of manufacture and engine number of the PCMs you’re swapping matches.

2. How is the PCM different from an ECM?

Both the engine control module (ECM) and the PCM are computers that control the engine. However, while the ECM only controls the engine, the PCM oversees the engine and the car’s transmission.

Take Away

The signs of PCM failure are easy to spot. Whether it be the check engine light on the dashboard, engine stalling, high amount of emissions, poor fuel economy, or transmission problems, you won’t miss it.

Many of the symptoms of PCM failure can signal other engine issues as well. Before attempting any repairs, you should troubleshoot the engine to determine if the problem is PCM-related.

The PCM controls both the engine and the transmission, so it should always run smoothly. The best way is by preventing water from getting to the module and insulating it against harsh environments. If you notice any signs of failure, diagnose and fix the module immediately or have a mechanic look at it.

Who Worked on This?



I'm the guy responsible for ensuring that every blog post we publish is helpful for our reader.

Mahir Ahmed


I'm the guy responsible for ensuring honest, informative, accurate and helpful guide to the reader.

Leave a Comment