Powertrain Control Module (PCM) is a laborious and time-consuming procedure. This detailed guide aims to improve your comprehension of the signs and causes of a failing PCM. Because the ECU is closely linked to other parts of the engine management system and affects their operation, identifying a failing engine control unit (ECU/PCM) can be difficult.
Contemporary automobiles are intricate, with multiple systems collaborating to guarantee seamless operation. To keep up with their duties, they depend on computers such as the powertrain control module, or PCM.
In this reading, we’ll explore what a powertrain control module is, its function, diagram & part, symptoms, importance & how it work. We’ll also explore how to fix it & cost replacement.
Let’s begin!
What is Powertrain Control Module (PCM)?
A power-train control module, or PCM for short, is a control unit or automotive component found in automobiles. Usually, it is a combined controller that includes the gearbox control unit (TCU) and the engine control unit (ECU). Some vehicles, like many Chryslers, have three different computers: the PCM, TCU, and Body Control Module (BCM).
In general, these car computers are quite dependable. In a car or truck, the PCM typically regulates over 100 variables. There are hundreds of error codes that might appear, each of which signifies a problem with a different part of the vehicle.
Usually, the dashboard’s “check engine” light will illuminate when one of these issues arises. Essentially the “brain” of the engine control system, the PCM is one of perhaps more on-board computers.
Numerous sensors of various kinds located throughout the vehicle provide the PCM with its main inputs. The majority of them are focused on engine performance and management. The failure rate of these sensors is far higher than that of any computer.
Function
PCM Functions Overview
- Engine Management: Controls engine functions like fuel injection, ignition timing, air-fuel ratio, and emissions controls.
- Transmission Control: Manages gear shifts, transmission fluid pressure, and other transmission system aspects.
- Diagnostics: Monitors and diagnoses faults within the powertrain system.
- Adaptive Learning: Adjusts parameters to improve performance and efficiency over time.
Diagram & Part
Symptoms of a Bad Failing (PCM)
Here are the major sign of a failing powertrain control module:
Intermittent Cylinder Misfires
Intermittent misfires are a major sign of a malfunctioning PCM, which is a malfunctioning Engine Control Unit (ECU). The PCM uses sensor data to precisely control fuel injection, the ignition system, and overall engine timing, all of which are essential for proper cylinder firing.
Illuminated Check Engine Light
The check engine light is a component of the onboard diagnostic system in your car. The Powertrain Control Module, or PCM, tries to fix the issue when a particular component breaks down. If the problem is not fixed, the check engine light comes on. It’s also possible that the PCM misinterpreted the data it received, which would activate this light.
Fail to Start
In order for the car to start, the Powertrain Control Module (PCM) is important. Problems with spark plugs and fuel injectors, both of which are controlled by the PCM, are among the many ways that a PCM failure might appear.
How To Fix or Replace a Failing (PCM)
Here are the main steps to fix your car (PCM) when it fails:
Visual Inspection
Now, the first thing you should do is look for corrosion or a disconnected wiring on your automobile before doing any repairs. Although it is the simplest to determine, this is not the most frequent reason for a PCM failure.
Check Your Battery
Use your multimeter to make sure your battery is fully charged while you’re working under the hood. Whether the engine is running or not, it should read at least 12.6 volts or 13.7 volts.
Retest after charging your battery completely if it displays less than that. This is crucial because low voltage can lead to the failure of some sensors, which keeps your PCM from receiving the input it needs to adapt properly.
Code Scanning
The next step is to connect an OBD or OBD II code scanner to your car to check for OBD error codes coming from the PCM if your battery is fully charged and there isn’t any apparent corrosion. You may use these codes to identify the specific systems that are failing, which can be very useful in repairing a lot of mechanical and electrical issues.
The P0603 code, the U0100 code, the P0113 code, and the P0606 code are among the PCM-related error codes that we have already discussed. The most often shown error codes are included in this list, which is obviously not all-inclusive.
Inspect Wiring & Sensors
This can be a challenging phase, so hopefully you were able to complete the prior one with some success. The cables that link the sensors to your PCM should also be inspected. You can identify which sensors or wiring are malfunctioning by looking for a PCM code, or two, or three.
These wires should be visually inspected and verified with a voltmeter. Additionally, since ground wires and connecting points are common sources of issues, don’t forget to inspect them. Reset your car’s codes after replacing any damaged parts, then take a long drive. You’ll probably have found a solution to the issue.
Consider an Alternative
You might need to attempt operating your car with a replacement PCM if all else fails or to verify certain fixes. Make sure the PCM is the right version for the same year as well as your make and model. Performance will improve right away if it turns out that your PCM was defective.
Importance of (PCM) In Modern Vehicles
In modern vehicles, the PCM manages the engine and gearbox in a comprehensive way. This part controls almost everything that happens beneath the hood, including as fuel injection, ignition timing, and air-to-fuel ratios, much like a conductor in a symphony.
By managing internal temperature settings and automatic traction, the PCM also improves your car’s general driveability. Significant performance problems, such decreased fuel economy and elevated emissions, might result from a damaged or malfunctioning PCM.
How Powertrian Control Module Work
These are the sensors that detect the amount of air entering the engine and exiting the exhaust, the temperature of the coolant, the distance between the accelerator pedals, the speed at which each wheel is rotating, and other variables that provide signals to the PCM.
Using that data, it then makes dozens of choices every second, including when to fire the spark plugs, how much gasoline to go into each cylinder, and when to change gears in an automatic gearbox to provide the greatest performance under the circumstances.
The PCM is sometimes referred to as the “engine control module” or “electronic control unit” in automobiles. Because the gearbox responds to what the engine is doing and vice versa, certain, mostly older models, have independent control modules for the engine and automatic gearbox that communicate constantly with one another, much like best friends on their iPhones.
Performance is smooth and efficient when the information flow between the PCM and other onboard processors and sensors is functioning correctly. The PCM can make the required adjustments without any problems.
When everything is going well, PCMs may be quick and intelligent, but when things go wrong, they can be completely stupid. For instance, the PCM will be scratching its digital head and unable to determine how to modify the air-fuel combination entering the engine if an oxygen sensor in the exhaust system malfunctions.
The engine may run rough, accelerate slowly, or have other problems. The check-engine light will likely illuminate, signalling for assistance. Similarly, the engine won’t start if the PCM fails.
PCMs are frequently mistakenly blamed for an engine issue or check-engine light since they depend so largely on inputs from other sources. Mechanics examine PCMs and often check inputs to ensure that the PCM is the cause before replacing it, even if the check-engine light’s fault code indicates that it is.
How Much does a Cost of replacement of PCM?
A powertrain control module replacement typically costs between $1,028 and $1,098. The brand, number, and condition of the item, as well as the characteristics of your car, all affect the pricing.
The cost of parts alone for an aftermarket PCM replacement might range from $50 to $1000.
You should budget an additional $100 to $300 for labour if you want your broken PCM replaced by a professional. Naturally, this is only an estimate and might change based on your car and local prices.
FAQs
What does the powertrain control module do?
The PCM plays a comprehensive role in managing the engine and transmission in modern vehicles. Like an orchestra conductor, this component regulates just about everything going on under the hood, including fuel injection, ignition timing and air-to-fuel ratios.
What happens when the powertrain control module goes bad?
By gaining a clear understanding of the PCM’s main functions, you can easily identify potential symptoms that might indicate a faulty PCM. Common signs of a malfunctioning PCM include engine misfires, stalling, decreased fuel economy, or issues with transmission shifting.
How do I reset my powertrain control module?
How to Reset PCM
Open the hood and look for the car battery.
Remove the negative battery cable.
Wait for around five minutes.
Turn the headlights on with the battery disconnected to empty the power in the capacitors.
Put the terminal back on again.
What are the symptoms of a bad PCM module?
When the PCM is not working correctly, the most common symptom is a lack of engine power, and the Check Engine Light illuminates on your dashboard. However, you may also notice poor fuel economy, increased emissions, and shifting problems.