2020 Peterbilt 579 Key Fob Programming Guide

Quick reference

Step-by-step on-board programming

Unfortunately, the 2020 Peterbilt 579 does not support on-board, or "DIY," key fob programming. Unlike some older passenger vehicles that use a series of key turns and button presses, modern heavy-duty trucks like the 579 have sophisticated security and immobilizer systems to protect the high-value asset.

Programming a new key fob and its integrated transponder chip requires specialized diagnostic scan tools that can securely communicate with the truck's Engine Control Unit (ECU) and immobilizer module. This is a necessary security measure to prevent unauthorized key duplication and vehicle theft.

To have a new key fob programmed, you will need to contact a Peterbilt dealership or a qualified automotive locksmith who has the appropriate diagnostic equipment for heavy-duty commercial trucks.

Battery replacement

If your key fob has a diminished range or has stopped working, replacing the battery is an easy first step. You'll need one CR2032 coin battery.

1. Locate the Seam: Look along the side of the plastic key fob case. You will see a small seam where the two halves of the fob are joined.
2. Pry Open the Case: Insert a small flathead screwdriver or a plastic pry tool into the seam. Gently twist to separate the two halves of the fob. Work your way around the case if necessary.
3. Remove the Old Battery: The CR2032 battery will be visible on the circuit board. Note the orientation—the positive (+) side should be facing up.
4. Insert the New Battery: Slide the new CR2032 battery into place, ensuring the positive (+) side is facing up, just like the old one.
5. Reassemble the Fob: Align the two halves of the key fob case and press them firmly together until they snap shut.
6. Test the Fob: Test the lock, unlock, and any other functions to ensure it's working correctly.

Where to buy a replacement fob

You have several options for sourcing a new fob, each with its own pros, cons, and cost implications.

• Peterbilt Dealership: This is the most expensive but most straightforward option. They will provide a genuine OEM (Original Equipment Manufacturer) fob and have the technicians and tools to program it to your truck. Expect to pay a premium, often in the range of $150–$250 for the fob itself, plus an additional one-hour labor charge ($100–$200) for programming and key cutting.

• Automotive Locksmith: A qualified mobile locksmith is often the most convenient and cost-effective choice. They can typically source both OEM and high-quality aftermarket fobs, and they carry the necessary diagnostic tools to program them on-site. The total cost for the fob, cutting, and programming from a locksmith is generally lower than the dealer, often falling in the $200–$350 range for the complete service.

• Amazon or Online Retailers: You can find replacement fobs online for as little as $30–$60. While this is the cheapest way to acquire the hardware, you will still need to hire a locksmith or visit a dealer to have the key cut and the fob programmed. Be cautious of quality, as some aftermarket fobs may have a shorter lifespan or reduced range. This route requires you to coordinate the purchase and the subsequent programming service separately.

If on-board programming isn't supported

The requirement for professional programming is rooted in the truck's immobilizer system. The key fob for your 2020 Peterbilt 579 is more than just a remote control; it contains a transponder chip. This chip holds a unique security code that is wirelessly read by an antenna around the ignition cylinder when you start the truck.

For the engine to start, the code from the transponder chip must match the code stored in the truck's immobilizer module. If the codes don't match—or if no code is detected—the immobilizer will prevent the engine from starting, even if the physical key turns the ignition.

When a new key is added, a technician uses a scan tool to put the truck's computer into a secure "learning mode." The tool then pairs the new transponder chip's unique code to the vehicle. This process ensures that only authorized keys can be used, providing a robust layer of security against theft. Given the value of your tractor and its cargo, this advanced security is an essential feature.

Find a mobile locksmith or shop on Repairius.