When your Jeep Cherokee isn’t performing as it should or if it’s not driving at all, one of the important components you should check is the powertrain control module (PCM). The PCM is a special vehicle component essential to your Jeep Cherokee’s well-being. After all, without a PCM, your Cherokee won’t function as it should. I have firsthand experience with malfunctioning and broken PCMs, and I can attest to how much of a headache diagnosing, fixing, and replacing one can be.
In my opinion, it’s imperative to determine if your PCM is negatively affecting your Cherokee. The PCM is responsible for operating numerous parts of your Cherokee, including the anti-lock brakes, air-to-gas ratio, gear changing, ignition timing, and performance.
Essentially the PCM controls your engine and transmission, so if the PCM is experiencing problems, you will encounter many adverse side effects while driving. The last time my PCM died, I was stranded on the highway and had to employ some quick thinking to navigate my vehicle to the side of the road. It was a harrowing experience; it taught me to pay attention to PCM failure signs and prompted me to remember routinely checking my PCM.
Additionally, I truly hate to be the bearer of bad news, but although the Jeep Cherokee is one of the very best models in the brand’s lineup, it’s known for experiencing its fair share of PCM problems. In my article, I will discuss a few of the common Jeep Cherokee PCM problems the enthusiasts at 4×4 reports have identified. I’ll also discuss nearly everything you need to know about a PCM, including how to test if it’s working and what causes it to fail. So, without further ado, let’s dive in!
Bottom Line Up Front
Jeep Cherokees often experience PCM problems. Common problems include random OBD II error codes, false check engine light signals, poor performance, starting and stalling issues, rough idling, and circuit board damage. Luckily you can easily test if your PCM is faulty or broken, and many devices can help you, like the MOTOPOWER MP69033.
What Causes PCM Failure?
Before taking a closer look into the common Jeep Cherokee PCM problems, we want to share some likely causes of your PCMs failure.
- Firstly, you must know that PCMs are typically manufactured to last longer than your Cherokee sensors. That’s why generally, the reason your PCM will break is because of a software problem and not an internal hardware problem.
- Secondly, PCMs also break often because of a shortened component or circuit power surge overload.
- They also encounter charging system failures that prevent them from powering and operating the various functions of your Jeep Cherokee.
- Environmental issues are another major reason they break. For example, if you’re frequently driving your Cherokee in a moist climate with extreme temperatures, you could encounter PCM failure with these environmental conditions.
What Are The Six Common Jeep Cherokee PCM Problems?
Experiencing PCM problems can be frustrating. I’ve spent countless hours scratching my head, trying to determine what exactly is causing my Cherokee to malfunction. I want to share the common Jeep Cherokee PCM problems to save you some trouble. The issues below occur when a PCM is not controlling the functions of your Cherokee.
Interesting Read: Jeep Cherokee Bad Ground Symptoms.
1. Your Engine Is Stalling Or Misfiring
Your Cherokee’s PCM controls your fuel injection and determines when it is the best time for you to switch gears. It could be your PCM at work if you hear a grating sound when trying to change gears. When your PCM is not working because of corrosion affecting the connectors or a computer error, it can lead to problems with your engine, like misfiring, stalling, and rough idling.
2. It Shows Random OBD II Error Codes
The most common Cherokee PCM problem may be error codes known as OBD II codes. Often many Jeep Cherokee owners report experiencing random error codes when driving their Cherokee, even when they know for a fact nothing is broken on their vehicle. If this sounds like you, your PCM could be faulty, which is why it’s showing random error codes.
Software issues or failing hardware components could be responsible for PCM OBD II error codes. In my experience, software problems are usually the culprits.
Since there are 5000 manufacturer-exclusive and generic OBD II codes, it can be challenging to determine when your Cherokee is showing error codes. Typically you can tell if you’re experiencing a PCM problem if you are getting odd codes that begin with ‘P06.’
3. Your Jeep Cherokee Struggles To Start
When a PCM is failing, your Cherokee could struggle to start. This is because the PCM controls the functions of your engine by ensuring every fluid and component does what it’s supposed to do. If you own a 1994 Jeep Grand Cherokee, this is one of the most common PCM issues.
In addition, your PCM will coordinate the timing of your ignition. If the PCM isn’t controlling the timing, the spark plugs don’t ignite, leading to issues starting your Cherokee. To identify if it is a PCM problem causing your Cherokee not to start, you need to determine if the car is cranking over.
4. Circuit Board Damage
Unfortunately, one of the most significant problems contributing to PCM issues is loose connections, shorts, and corrosion. These issues lead to circuit board damage which can affect many aspects of your vehicle.
This is especially true in Jeep Cherokee models, as many owners have reported having electrical system problems, and I experienced this issue when I owned a 2000 model. It was expensive to fix the circuit board damage and time-consuming to find everything that had been negatively affected.
The best way to fix this situation before it occurs is to solder the 5-volt power connection if a loose connection is responsible. If you don’t, you risk experiencing circuit board damage. If corrosion has caused the circuit board damage, you’ll need to replace your PCM with a new one and any other broken Cherokee auto parts.
5. Your Check Engine Light Is On
Often a faulty PCM can provide wrong inputs. Many Jeep Cherokee owners have had issues with their check engine light and power steering because of a PCM fault. For example, some Cherokee owners (myself included) have said their check engine light turns on randomly.
However, you should note that a check engine light randomly turning on can be a different fault. You could have faulty 02 sensors or emissions problems.
Taking your Cherokee to a reputable mechanic to determine why your check engine light is turning on randomly is usually the best course of action. This is because a mechanic has the specialized tools to determine if a PCM problem is causing this light to go on all the time. A mechanic can also fix the issue. If you don’t want to go to a mechanic, you can use an OBD II code reader to troubleshoot your check engine light.
Additionally, if your check engine light continues to turn on after you have replaced your PCM, it could mean there is another issue, or you could have a faulty PCM installed.
6. Poor Performance
Poor performance is one of the biggest problems when your PCM isn’t working because of software issues. Numerous errors could be made, but some of the most common include messing up the air and fuel mix. When this happens, your PCM doesn’t send your Cherokee’s engine the amount of fuel it needs to operate properly.
After all, if there’s too little fuel, your engine won’t function as it should, and it could even jerk or stall. If you leave this to continue and don’t address the issue, you could be left with a permanently damaged engine. Trust me; this is truly something you don’t want to happen as it is even more expensive to replace an engine and a PCM. We’re talking in the thousands! More than $10,000, to be exact.
How Do You Check If Your Jeep Cherokees’ PCM Is Working?
If you’re encountering problems with your Jeep Cherokee and suspect it could be due to a PCM fault, it’s an excellent idea to learn how to check your PCM. Below I have briefly detailed how to check your PCM, and you’ll likely be pleased to learn it’s a simple process.
Yet, this is a rudimentary test procedure, and you will have to seek a professional for a more detailed investigation. Additionally, you’ll need a few items to perform the test, like a multimeter, flashlight, screwdriver, and an OBD II code scanner.
Step One: Conduct A Visual Inspection
Before you decide to take out your PCM and put in a replacement one, you need to conduct a visual inspection. The first things you need to check for are rust and disconnected wires. If you find rust or disconnected wires, it’s a sign that your PCM could be failing to do its job.
Additionally, while looking at your battery and where it’s connected to your PCM, you need to ensure there is no rust on your PCM or wiring. Should you see loose wires, you can easily reconnect them, and if there is corrosion, you will want to take your Cherokee to a mechanic.
Step Two: Safely Check Your Cherokee’s Battery
For this next step, you will need to use your multimeter. You will use your multimeter to check that your battery has a full charge. If your battery has a reading of a minimum of 12.6 volts with the engine off and a reading of 13.7 volts with it switched on, there likely isn’t any problem.
This is important because having a low battery voltage reading could cause certain sensors in your Cherokee to fail. This will deprive your PCM of the input it needs to receive from your vehicle to make adjustments to ensure your Cherokee operates as it should.
Step Three: Use An OBD II Scanner To Scan For Error Codes
One of the most important troubleshooting steps when checking your PCM is using an OBD II scanner. An OBD II scanner plugs into your Cherokee to show if your PCM produces any OBD II error codes. This is helpful as the codes it displays can help diagnose problems with your vehicle and tell you if you need to replace your PCM.
Step Four: Carefully Inspect Your Cherokee’s Sensors And Wiring
After using your OBD II scanner to establish if there are error codes, you need to inspect your Cherokee sensors and wiring. You can check which sensors and wires connecting to your PCM are faulty with your error codes by following the areas pinged as potential problems.
To start, you need only perform a visual inspection, and once you find wiring or sensors that could be an issue, you can check them with a multimeter. Additionally, don’t be like me and forget to check connection points and ground wires, as those have been the cause of my PCM issues in the past.
If it was a wiring or sensor problem and you have replaced any failed components and reset the codes, you shouldn’t have any further PCM problems. Yet, if you’re still encountering problems, it might be time to chin up and pay the exorbitant fee it costs to replace a Cherokee PCM.
What Are The Three Best OBD II Code Scanners To Use On A Jeep Cherokee To Determine PCM Failure?
Above I spoke about testing if your PCM is faulty or broken. Now I’m going to speak about the OBD II code scanner you can use to make testing your PCM easier. To determine PCM failure in your Jeep Cherokee, you need to use a quality OBD II code scanner to test your PCM. Below I have found three of the best scanners you need to consider if you suspect your PCM is faulty or broken.
1. MOTOPOWER MP69033 Code Reader
I hate checking for PCM problems with a complicated OBD II code scanner. Even though I’m technically inclined, I don’t like to waste time on troubleshooting and prefer spending time fixing and upgrading my Cherokee so I can get back out on the road and to my latest adventure. You might want to use the MOTOPOWER MP69033 code reader if you’re the same.
This LCD display code reader has multiple innovative functions that make it worth the price. For example, with this scanner, you can check more than PCM codes. You can also determine the cause of an erase code, a check engine light, and a read code.
2. FOXWELL NT301 OBD II Scanner
If you hate getting messed around and want to solve your PCM problem quickly without tinkering too much, you need the FOXWELL NT301 OBD II code scanner. This mechanic-recommended scanner is one of the most accurate on the market.
It can easily turn off your check engine light, locate bad 02 sensors, and retrieve VIN for your Cherokee. Yet, its accuracy truly comes into play with its live data graphing and logging. With these graphs, you can focus on suspicious trends and patterns with your Cherokee.
3. INNOVA 5210 Diagnostic Code Scanner
One of the best OMB II code scanners for diagnosing PCM problems is the INNOVA 520. It might not be my favorite option, but it is still one of the better choices when it comes to code scanners. The INNOVA 5210 diagnostic code scanner offers drivers enhanced coverage and functionality because it can read and clear OBD codes and display your Cherokee’s vehicle information from when a trouble code was triggered.
With this device, you can also check your car’s speed, oil temperature, and RPM information to ensure it’s performing as it should. Yet, you’ll likely love the most that it comes with a convenient RepairSolutions2 app available on the Apple App Store and Google Play.
What To Look For When Buying A Jeep Cherokee PCM Replacement
If you have checked your PCM and determined that it needs to be replaced, it’s best to know what to keep in mind before you start looking for one to buy. After all, for most motorists looking for a new PCM can be overwhelming since there are so many options available on the market. That’s why I have listed the factors you need to consider when debating which PCM to purchase. I don’t want you to waste money buying an expensive PCM that isn’t suitable for your Cherokee.
1. Does It Fit Your Jeep Cherokee?
Arguably, the first thing you need to consider when looking for a replacement PCM for your Jeep Cherokee is if it will fit. Many motorists make the mistake of buying a PCM only to have it not fit because it hasn’t been specifically designed for their Jeep.
That’s why it’s best to always check how the PCM fits in your Cherokee before you buy it. You need to know your vehicle’s year and model to find the right part. Should you be unsure, you needn’t worry because you can refer to your PCMs replacement part number, usually found on your old PCM or in a manufacturer’s catalog.
2. Is It In Good Condition
It might be a surprise, but you can purchase PCMs in new and refurbished conditions. The main difference is that a new PCM is built with new materials and components, while a refurbished PCM has been used but is still usable after going through an upgrading process.
Often refurbished PCMs will be cheaper than brand new ones, but they won’t be the same quality. Before putting it into your Cherokee, you must check the condition of a PCM regardless of whether it’s new or used. Not only could you risk wasting money, but you also put your safety at risk if you buy a part that isn’t in good condition. Trust me; I know.
3. Can You Trust the Manufacturer?
Unfortunately, not all Cherokee PCMs are made equally. Some brands manufacture better quality PCMs than others. That’s why you need to ensure you’re purchasing a replacement PCM from a brand you can trust.
You also need to ensure the PCM you choose is made with high-quality materials and is durable. If it isn’t, you risk many inconvenient situations, like your Cherokee shutting down while driving. As you know, I have experience with this, and it isn’t pleasant.
Frequently Asked Questions
Question: How Do You Reset Your Jeep Cherokee’s PCM?
Answer: Resetting your Jeep Cherokee’s PCM is not as challenging as you might have been led to believe. Have a look at the super simple steps below.
• Find your positive battery terminal and disconnect it. Once it’s disconnected, touch it to the ground for up to 30 seconds to discharge the PCM capacitors. Doing this will maintain the adaptive memory of the part.
• Reconnect the battery cable and turn your ignition switch to the ‘on’ position. However, under no circumstances should you start the engine yet.
• Then turn the headlights on and off before turning the ignition key off.
• Once you have finished doing this, your engine will reset and run off a set of pre-programmed tables that came with your PCM.
Question: Are A PCM And ECM The Same Thing?
Answer: Many people ask if a PCM and an ECM are the same. Although these two components are often mistaken for each other, they are different. The primary difference between the two parts is that a PCM is used in newer models to control nearly all engine functions, and an ECM is used in older models to control specific engine functions.
Question: How Much Does Replacing A Jeep Cherokee PCM Cost?
Answer: Unfortunately, if you determine that you need to replace your Jeep Cherokee’s PCM, you will need to part with a somewhat large sum of money. Since a PCM is a miniature computer for a vehicle, it costs more than certain other automotive components.
On average, replacing your Cherokee’s PCM could cost you between $800 and $1,500, depending on the year model. However, labor only costs around $100 to have it installed.
As you now know, there are many common Jeep Cherokee PCM problems. Luckily it’s not the end of the world if you’re encountering a faulty or broken PCM. Although replacing a broken one could cost you a small fortune, it’s usually a quick and straightforward fix.
With the right tools like the MOTOPOWER MP69033 OBD II code scanner, you can resolve your PCM problems quickly and efficiently if you have auto-knowledge.
If not, a mechanic can help you locate the exact cause of your PCM problem and address it. The sooner you discover the problem with your PCM, the quicker you can fix it before you’re left with more damage and potentially months homebound.
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