2000 Jeep Grand Cherokee Key Fob Programming: Your DIY Guide

Lost your key fob or need to program a new one for your 2000 Jeep Grand Cherokee? While some sources might point you to dealership-only programming for WJ models like yours, there’s a method you can accomplish yourself using readily available tools. This guide will walk you through programming your 2000 Jeep Grand Cherokee key fob, saving you time and potentially money.

Understanding Key Fob Programming for Your 2000 Jeep Grand Cherokee

The Remote Keyless Entry (RKE) system in your 2000 Jeep Grand Cherokee is managed by the Passenger Door Module (PDM). This system allows you to program up to four key fobs, each assigned to a memory slot within the PDM. Official documentation, like the “Daimler Chrysler North American Remote Keyless Entry Programming Procedure,” might suggest that dealer-specific tools (DRB III) are required for WJ models. However, this isn’t entirely the case.

This guide focuses on a Dealer Programming Method (Method C from the official documentation) that can be adapted for DIY use. Instead of the DRB III tool, we’ll utilize an ELM327 based OBD2 interface and RS232 terminal software. This approach allows us to communicate directly with your Jeep’s computer system and program the key fob. This method has been tested and proven to work on 2004 Grand Cherokee WJ models and is highly likely to be effective for 1999-2004 models.

Tools You Will Need

To program your 2000 Jeep Grand Cherokee key fob, you’ll need the following:

• A new key fob: Ensure it is compatible with your 2000 Jeep Grand Cherokee.
• ELM327 OBD2 interface: This device acts as a bridge between your computer and your vehicle’s OBD2 port. These are widely available online.
• RS232 terminal software: This software allows your computer to communicate with the ELM327 interface. Examples include PuTTY (free and widely used) or Tera Term.
• A computer with an RS232 port or a USB to RS232 adapter: To connect your computer to the ELM327 interface.

Step-by-Step Key Fob Programming Procedure

Before you begin, ensure your Jeep Grand Cherokee’s ignition is in the “ON” position, but the engine is not running (KOEO – Key On, Engine Off).

1. Setting Up the ELM327 Interface:

   You’ll need to use AT commands to configure your ELM327 interface. Open your RS232 terminal software and connect to the COM port associated with your ELM327 interface. Type the following commands one by one, pressing “Enter” after each:

   • AT L1 (Enables line feeds in responses for better readability)
   • AT H1 (Enables header bytes in commands)
   • AT E1 (Enables command echo, so you can see what you’re typing)
   • AT SP2 (Sets the communication protocol to VPW – Variable Pulse Width modulation, used by Chrysler vehicles of this era)
   • AT RA A1 (Sets the receive address to A1 to view responses from the Passenger Door Module – PDM)
   • AT SH 24 A1 31 (Sets the header bytes for commands to the PDM. 24 A1 31 is the header specific for communicating with the PDM for RKE programming in this context.)

2. Entering Programming Mode:

   Now, send the command to put the RKE system into programming mode. Type the following command and press “Enter”:

   • 00 00 00 (This, combined with the header bytes set previously, sends the complete command 24 A1 31 00 00 00 to initiate programming mode).

   If successful, the vehicle should respond with:

   • 26 A1 71 00 00 00 (This response confirms that the RKE system has entered programming mode).

3. Specifying Memory Slot:

   Next, you need to specify which memory slot to program for the key fob. Slots are numbered 01, 02, 03, and 04. If you are programming the first key fob, or overwriting the first slot, use 01. For the second key fob, use 02, and so on. Type the following command, replacing XX with the desired slot number (e.g., 01, 02, 03, or 04), and press “Enter”:

   • XX 00 00 (For example, to program to slot 1, type 01 00 00. This sends the complete command 24 A1 31 01 00 00.)

   A successful vehicle response will be:

   • 26 A1 71 XX 00 00 (Confirming the memory slot is selected).

4. Programming the Key Fob:

   Immediately after sending the memory slot command, take the key fob you want to program and press and hold either the “Lock” or “Unlock” button. Keep holding the button until you hear the door lock relays activate. This usually happens within a few seconds. The sound of the door locks clicking indicates that the key fob has been successfully programmed to the selected memory slot.

5. Programming Additional Key Fobs (If needed):

   If you have more key fobs to program, repeat steps 2 through 4, incrementing the memory slot number (XX) for each subsequent key fob. For example, for the second key fob, use 02 in step 3, for the third, use 03, and so on, up to 04.

6. Finalizing Programming:

   Once you have programmed all desired key fobs, turn the ignition OFF. This action terminates the programming mode.

Important Considerations and Safety Precautions

• Existing Key Fobs: If you already have a working key fob, it is likely programmed to memory slot 1. You can program new key fobs to slots 2, 3, and 4 without affecting the existing one. Alternatively, you can reprogram slot 1 or any other slot, potentially overwriting a previously programmed key fob in that slot. The slot numbers do not need to be programmed sequentially.
• Proceed with Caution: Interfacing with your vehicle’s OBD2 port involves sending commands to its computer system. While this procedure has been tested and found to be safe, proceed with caution and at your own risk. Incorrect commands could potentially cause unexpected behavior.
• Vehicle Compatibility: This procedure is specifically tested on a 2004 Jeep Grand Cherokee WJ and is expected to work for 1999-2004 WJ models. Compatibility with other Jeep models or years is not guaranteed.

Conclusion

Programming your 2000 Jeep Grand Cherokee key fob yourself is achievable with the right tools and this step-by-step guide. By using an ELM327 interface and terminal software, you can bypass the need for dealership tools and regain control over your vehicle’s remote access. Remember to follow the instructions carefully and proceed with caution when interacting with your vehicle’s OBD2 system. This DIY method offers a cost-effective and convenient solution for 2000 Jeep Grand Cherokee Key Fob Programming.