6 Symptoms Of 7.3L Powerstroke PCM Failure (Detect Now)

PCM controls the engine and transmission (only if automatic) of 7.3 Powerstroke. The computerized system surely is amazing because you don’t have to constantly monitor all the parts.

But the disadvantage is that any fault in a single microchip can cause lots of issues.

So, I have gathered all 7.3L Powerstroke PCM failure symptoms so that you can understand a problem and act accordingly.

What Are the Signs of a Bad PCM on a 7.3L Powerstroke?

Seeing the engine lights on for no reason is the sign of a bad 7.3 Powerstroke PCM. 

As the warning lights can be turned on for valid reasons, you should check the engine. 

After seeing that that are no issues with the hardware, you can safely assume that the central computer control system has gone bad. 

7.3L Powerstroke PCM Failure Symptoms:

You can understand that knowing how to detect a bad 7.3 Powerstroke PCM is important. 

The sign is obvious but you may face different symptoms in your particular case. Let’s check them out. 

1. Having Starting Problems

Not starting at all or requiring several attempts can indicate a faulty PCM. 

It can cause an improper fuel-to-air ratio. Also, poor engine timing and short in the wiring harness are probable reasons. 

Regardless of the symptom, anything related to starting the engine should be taken care of immediately to avoid more damage. 

2. Poor Gas Mileage

As PCM controls the gear shifting time, a problem in its function can hurt gas mileage. 

Now, don’t think that it is the only reason for a poor or sudden loss of gas mileage. The wisest move is to check the engine by a mechanic.

Read Also: 6 Symptoms Of 6.0 Powerstroke PCM Failure: (Detect Now)

3. Bad Engine Performance

As PCM controls several mechanisms, it is understandable that improper functioning results in poor performance.

For example, the engine may not get the proper amount of fuel to run at its full potential. One can face jerking and stalling. 

On the other hand, too much fuel can cause flooding, decreased fuel economy, and too much carbon emission. 

One easy way to detect is by doing an emission test of your car’s engine. Though ECM is responsible for maintaining the right level of emission, the PCM can also be a problem sometimes. 

4. Shifting Problem

Automatic shifting is one of the main features of modern vehicles. PCM oversees that functionality. 

When the circuit goes bad, you may see that the gear is shifting on its own unnecessarily. In this case, you can definitely blame the PCM. 

5. Intermittent Running Problem

Due to bad PCM, your car can have intermittent running and stalling symptoms. Also, you will notice continuous ‘Check Engine Light’ turning on and off. 

But make sure that the CPS is okay because that is often the cause of the problem. Then, you can move on to checking the module. 

One owner mentioned that he experienced complete shut down at only 60 MPH and at idling. His mechanic told him to replace the PCM as it had become faulty.

Read Also: 5 Symptoms To Detect ICP Sensor Failure On 7.3 Powerstroke

6. Gauge Cluster Not Functioning Right

Besides those common symptoms, another situation was mentioned by a 7.3 Powerstroke user. 

He told that this truck’s gauge cluster was not working right. Installing the block heater, and plugging it in started the problem.

Trying to start the truck without a block heater, the engine emitted white smoke through the exhaust and cranked a few times. 

After running some diagnostics, the mechanic told him that its PCM was bad causing the problem. 

Pro Tip: Regularly, car owners should load test batteries as they often cause the misfunctions of different parts. Before blaming the PCM, check the batteries first.

Read Also: Low Fuel Pressure On 7.3 Powerstroke:(7 Symptoms To Detect)

What to Do When You Detect A Bad PCM on 7.3L Powerstroke?

From the above discussion, you must have realized that the signs and symptoms can happen due to lots of different engine parts other than PCM.

So, the first logical step is to perform basic troubleshooting assuming the PCM is not the culprit.

After confirming other parts’ proper functionality, you should perform a computer diagnostic. 

Then, you won’t have any confusion. As it won’t be possible to repair a powertrain control module, you will have to replace it.  

If the problem is a glitch in the software, installing an updated version will solve the issue. You can try it too.

Is Replacing A Bad PCM on 7.3L Powerstroke Typically Expensive?

Yes, it is expensive because the module is a very critical system controlling different mechanisms and timings. 

But prices of new PCMs vary due to their different complexity levels. 

For a 7.3 Powerstroke Ford engine, the cost can vary from $150 to $500. Also, factor in approximately $120 as the labor charge of the mechanic. 

More expert mechanics or reputed shops can charge even more. However, you can avoid that cost by installing it yourself.

There are lots of YouTube videos to see clear instructions.

One can also update the software by themselves. Otherwise, it can cost from $80 to $120 approximately for expert installations.

Read Also: 7.3 Powerstroke Bad Exhaust Back Pressure Sensor Symptoms

How Often Should You Inspect 7.3L Powerstroke’s Powertrain Control Module?

As PCM does not spin or move like other parts in a vehicle, wondering why it gets faulty or non-functional is a valid question.

Due to heat and vibration, the internal circuitry can be affected severely. As a result, communication and coordination between different mechanisms get interrupted. 

All things considered, it is not possible to set a timeline for PCM maintenance. When you do routine engine inspection, you can run a computer diagnostic at the same time. 

Such regular checking can reveal possible issues of PCM which can appear in near future.  

Final Thoughts

Older modules required reprogramming. But it is not the case for the newer ones.

And, updating the software is still necessary for proper functioning. 

I hope that you have some valuable insights from the 7.3 Powerstroke PCM failure symptoms.

Now, you know where to look for those issues.

Read Also: 4 Symptoms To Detect A Weak Fuel Pump On 7.3 Powerstroke

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