Transponder chips explained: ID46, ID47, ID48, 4C, 4D and 8A
Which chip families clone, which have to be programmed through the immobiliser, and how to identify what you are holding without guessing from the vehicle.
The chip decides the whole job, because it decides whether a key can be copied at the bench or has to be written into the car. Get it wrong and you have bought a blank that will never start anything.
Fixed code: the ones you can clone
A fixed code transponder answers the same way every time it is challenged, which is what makes it copyable. The vehicle is never involved.
- 4C: early, simple, cloned by almost any device.
- 4D: a large family and the workhorse of cloning work.
- ID46: a crypto transponder that can usually be cloned, though the tool calculates rather than copies, so it takes longer.
Rolling code: the ones you have to program
These change their answer each time, so there is nothing static to copy. A new key has to be written into the immobiliser itself.
- ID47: widely used, programming only in general.
- ID49: a later generation, programming only.
- 8A: common on more recent vehicles, programming only.
Identifying what you are holding
The chip type is sometimes printed on the key or on the transponder glass. Where it is not, a transponder reader identifies it in seconds and is the single tool worth owning if you do this daily. Where you have neither, the OEM part number on the fob board narrows it to a family.
What does not work is inferring the chip from the vehicle. One model year can carry more than one chip depending on where the car was built and what was fitted.
Why this changes your quote
Cloning is a bench job: a device, a blank that accepts the family, and a way to cut the blade. Programming needs the vehicle present, a tool that supports the platform, and sometimes a security PIN read first. One is fifteen minutes in the workshop, the other is a call-out with a variable end time.
Establish the chip on the phone and you can quote honestly. Establish it on the driveway and you are renegotiating in front of the customer.
Matching a blank
A blank has to accept both the chip and the keyway. Getting one right and the other wrong is the most common ordering mistake in this category. Every blank listed here states its keyway code, and states the chip where one is fitted rather than the blank being empty.