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2002 Jeep Grand Cherokee PCM Problems

by Shasta Judy (2023-01-01)

PCM, also known as the Power Control Module, is a computerized system responsible for controlling the essential functions within a vehicle. Some of the main functions include transmission and anti-lock brakes. It also facilitates the vehicle's overall performance and controls the air-to-gas ratio inside the combustion cylinder.
The 2002 Jeep Grand Cherokee is one of the most powerful off-road SUVs. It performs well on paved, unpaved, and snowy roads. Reviews given by owners of the 2002 Jeep grand Cherokee claim that the powerful engine makes it perform better on all types of roads.
However, most reviews also indicated one common problem with the 2002 Jeep Grand Cherokee. Most owners complain about electrical and PCM problems. Since it has a complex engine, installing a faulty power control module is challenging. Most of the people who have tried replacing ended up damaging some parts leading to electrical system shorts, leaks, and corrosion.
Some of the major problems reported by owners and users of the vehicle include:
Displaying Random Error Codes
The Engine Control Unit and Transmission Control unit is found inside the PCM. Some car manufacturers refer to it as the Engine Control Module. The PCM installed on all 2002 Jeep Grand Cherokee contains sensors responsible for monitoring different elements to ensure that the engine is performing optimally.
Therefore, the Power Control Module generates different codes that display different dashboard warning lights when a problem occurs. The codes help mechanics determine the main problem and repair it.
However, a damaged may display random codes even when the car is not faulty. These random codes can be referred to as OBDII codes. The 2002 Jeep Grand Cherokee has 5000 generics and manufactured OBDII codes. However, when the PCM has problems, the code scanner will read codes starting with P06.
The Check Engine Light Comes on
Issues with the PCM can lead to other problems in the engine. It causes the check engine light to go on and creates issues with the power steering. Some of the main reasons why check engine warning lights include:
* Faulty emissions
* Damaged oxygen sensors and PCM problems
Engine Stalling and Misfires
Fuel injection is one of the major functions of the PCM. Therefore, problems within the PCM can lead to stalling and misfires. Users of the 2002 Jeep Grand Cherokee have complained about their vehicles stalling. Other signs of a damaged PCM include the car taking too long to switch from one gear to another, leading to jerks and unpleasant noises.
However, this problem might also be caused by other factors. Therefore, it is important to take your car for diagnostic before replacing the PCM.
It experiences Troubles when Starting
Vehicles may experience trouble starting due to several reasons such as dead batteries, damaged engines, fuel leaks, etc. However, a damaged PCM could also cause an ignition problem with your 2002 Jeep Grand Cherokee. The difficulty in starting is because of wrong information input by the PCM to the vehicle.
A completely damaged PCM cannot adjust the air-to-fuel ratio, and it may never start. However, it is important to diagnose other parts, such as the starter or alternator, before changing the PCM of your jeep.
Reduced Engine Performance
Since PCM controls the air-to-fuel ratio, it may lead to reduced fuel efficiency, acceleration rate, and engine power when damaged. It can also increase the fuel consumption of your vehicle to worse levels.
It also makes the vehicle unable to accelerate efficiently, especially when going uphill.
Damaged Circuit Board
The circuit board inside the PCM connects with other systems using a complex-wiring channel. Any physical damage to the system or corrosion can damage PCM. Most 2002 Jeep Grand Cherokee users have experienced the problem that causes issues with the entire electrical system of the jeep Grand Cherokee.
Faults in the wiring system make the battery die overnight, and lights come on randomly. It may also blow the 20A fuse found inside the engine block. Problems with the circuit board provide wrong codes that lead to damaged electrical gauges.
Users have reported several warning lights appearing on the dashboard, such as brake light, power steering, and check engine light. Replacing your PCM solves these problems temporarily since it does not consider the strained electrical system that wears out quickly, leading to engine and transmission issues.
It creates Transmission Issues
Note that this issue is only common in automatic Jeep Grand Cherokee. The PCM does not control transmission in cars with a five-speed stick shift. A faulty PCM in your Jeep causes the gears to shift randomly. However, checking the jeep PCM is only necessary if the problem persists even after replacing the automatic transmission fluid.
You begin to notice Problems with Sensors
The jeep's PCM is connected to sensors in different car parts such as the throttle body, radiator, and air filter. Problems in the PCM reduce the car's performance by creating unnecessary adjustments. These adjustments may take several repairs for them to function properly. In most cases, sensor issues do not mean a defective PCM. Sometimes you only need to replace the damaged sensor to see if it works properly.
What are the main reasons that led to your Faulty PCM?
Several reasons can lead to your 2002 Jeep Grand Cherokee PCM problems. Some of the main reasons for damaged PCM include:
* Wiring problems
* Dying batteries
* Water
* External factors such as vibrations and corrosion, especially when driving on rough roads
Your 2002 Jeep Grand Cherokee PCM may go bad due to the reasons mentioned above. It is important to do a 2002 jeep grand Cherokee PCM replacement using a well-refurbished PCM if this happens. The steps given on several websites may only offer temporary solutions to the faulty PCM.
Finding a new 2002 Jeep Grand GMC Sierra ECM Cherokee PCM is not easy since it is an old version. You can get a used PCM from similar models or find an experienced technician to repair the damaged one. PCM problems are common in most jeep models. Therefore, if you experience any problems with your 2002 jeep Grand Cherokee visit us for help.
How do you tell if jeep PCM is bad?
Various signs on your jeep indicate that you may have a damaged PCM. The most common symptom of a damaged PCM is randomly displaying codes starting with P06. Other major indicators of a faulty PCM include:
* Increased gas consumption
* It experiences starting problems
* Check engine light turns on
* Engine stalling and misfire
* Incorrect gear shifting
* Sensor problems become noticeable
How to Reset a PCM on a Jeep Grand Cherokee
When you encounter most of these problems and the PCM is okay, you may need to reset it. Resetting the 2002 Jeep Grand Cherokee is easy, and the steps include:
1. Unplug the positive battery connector and touch it to the ground for at least thirty seconds. This move discharges the capacitor but maintains the PCMs memory.
2. Reconnect the cable to the battery
3. Switch on the ignition but don't start the engine
4. Switch on the headlights
5. Switch off the headlights
6. Turn off the ignition switch
How do I test a Jeep PCM?
Testing your Jeep PCM may require a professional if you do not have the right equipment. However, connect it to the PCM if you own a diagnostic tool. The equipment will display all the problems within the entire system. It also allows you to decode the errors displayed on the screen back to normal.
What causes a PCM to go bad?
Most people cannot identify the main reason why the PCM went bad. Below are some of the main reasons that may have damaged your PCM
* When it comes into contact with water
* Vibrations
* Thermal stress
* Low voltage due to a dying battery
* Corrosion
* Wiring problems