The "computer" in your Jeep Cherokee, more accurately referred to as the Powertrain Control Module (PCM) or Engine Control Unit (ECU), controls various aspects of your vehicle's operation. Resetting it can sometimes resolve issues like a check engine light, erratic shifting, or poor fuel economy. However, it's crucial to understand why you're resetting it and that this isn't a fix-all solution. A proper diagnosis is always recommended before attempting any resets.
There are several ways to reset your Jeep Cherokee's computer, each with its own approach and implications:
Method 1: Disconnecting the Battery
This is the simplest method and often effective for minor glitches. It involves completely cutting off power to the PCM, forcing it to default to its factory settings.
Steps:
- Safety First: Ensure your Jeep Cherokee is parked on a level surface, the engine is off, and the parking brake is engaged.
- Locate the Battery: Typically found in the engine bay, but consult your owner's manual if unsure.
- Disconnect the Negative Terminal: Locate the negative (-) terminal (usually marked with a minus sign). Use a wrench to loosen and remove the cable clamp.
- Wait: Leave the negative cable disconnected for at least 15-30 minutes. This allows the system's capacitors to fully discharge. Some mechanics recommend leaving it disconnected for up to an hour.
- Reconnect the Negative Terminal: Carefully reattach the negative cable to the terminal and tighten the clamp securely.
- Start the Engine: Turn the ignition key to start the engine. The PCM will now reboot and relearn your driving habits. You may notice some slight changes in performance initially.
Important Note: This method clears various stored data, including radio presets and clock settings. You’ll need to reconfigure these after the reset.
Method 2: Using a Scan Tool (OBD-II Scanner)
This method is more precise and allows for targeted resets. An OBD-II scanner can read diagnostic trouble codes (DTCs), clear them, and sometimes perform more advanced resets.
Steps:
- Obtain an OBD-II Scanner: Many affordable scanners are available online and at auto parts stores.
- Locate the OBD-II Port: This is usually found under the dashboard, near the steering column.
- Connect the Scanner: Plug the scanner into the OBD-II port.
- Follow Scanner Instructions: Each scanner has a slightly different interface, but generally, you'll be able to navigate to a section that allows you to clear DTCs or perform a PCM reset. This is often labeled as "Clear Codes" or something similar.
- Confirm Reset: The scanner will confirm the reset is complete.
Benefits: This method avoids clearing unrelated data and can provide valuable diagnostic information.
Method 3: Specific Procedures for Certain Issues (Dealer/Mechanic)
Some problems require more advanced procedures than a simple battery disconnect or OBD-II reset. For complex issues or if the problem persists after trying the above methods, it's best to consult a qualified Jeep mechanic or dealership. They have specialized tools and expertise to diagnose and resolve the underlying problem.
Frequently Asked Questions (PAA)
Q: How long does it take for a Jeep Cherokee computer to reset?
A: The time it takes depends on the method used. A simple battery disconnect might take only a few minutes for the engine to restart, but the computer may take longer to relearn your driving patterns (up to several driving cycles). Using an OBD-II scanner for a PCM reset is generally quicker.
Q: Will resetting the computer erase my radio presets?
A: Yes, disconnecting the battery will usually erase your radio presets, clock settings, and other learned parameters. An OBD-II reset might not affect these settings, but it's always a good idea to check.
Q: Why is my Jeep Cherokee check engine light on after a computer reset?
A: If the check engine light remains illuminated after a reset, it indicates an underlying issue that needs to be addressed. The light is likely triggered by a diagnostic trouble code (DTC) that the reset didn't eliminate. You'll need to use an OBD-II scanner to read the code and determine the cause.
Q: Can I reset the computer myself, or should I take it to a mechanic?
A: The battery disconnect method is relatively simple to perform yourself. Using an OBD-II scanner is also straightforward for those comfortable with basic automotive technology. However, for more complex issues, consulting a mechanic is always recommended to ensure proper diagnosis and repair.
This guide provides general information. Always consult your Jeep Cherokee's owner's manual for specific instructions and recommendations. Remember, a proper diagnosis is crucial before attempting any computer resets.
