2001 Toyota 4runner
Key Replacement - Save vs Dealer in San Diego

2001 Toyota 4runner Remote Replacement - Fast, Affordable & Professional

I got a call from a guy parked near the library off Cuyamaca, out in the Fanita Ranch area of Santee. He'd already paid another locksmith to replace the key on his 2001 4Runner. New blade, new fob, the works. But the truck would crank and die every single time. The previous locksmith told him the immobilizer module was bad and walked away.

I've seen that call before. It's almost never the module.

When a Toyota key from this era cranks the engine but the vehicle shuts off immediately, that points to the transponder registration not completing fully. The immobilizer on these trucks uses a security handshake that has to finish completely. Rush it, skip a step, or lose connection mid-process, and the key writes a partial registration that doesn't hold. The engine fires on the crank, the fuel cuts, and the truck dies in two seconds flat. Every time. Looks exactly like a bad module to someone who doesn't know the system.

I connected through the OBD port with my programmer, cleared the bad registration, and ran the sequence clean from the start with the correct timing. Confirmed on screen that the key was permanently stored. Then I tested the fob functions separately since the remote side is its own circuit on these trucks.

Everything worked. The module was fine the whole time.

He'd already spent money on the first attempt. I can't fix that. What I could do was show him the confirmation that the job was actually done and done right, then hand him a key that started his truck without drama. That's what he needed, and we got there.

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