Hi! Buying a CPO 2017 Discovery and the keys for it were stolen so the dealer wanted to replace the entire PCM....I have no clue if this is just some runaround or I’m just cynical.
Anyway, is the replacement of the pcm necessary for the replacement of keys on a 2017 discovery land rover?
This mom is at a loss because I know nothing about this and I feel like they have no clue either! Please help. Thank you.

 

You might want to post this in the LR4 section as this area is mostly the older Discovery models.

 

If you just replace the keys then the old lost or stolen keys would still work and you'd be at a security disadvantage.
If the PCM is what the keys talk to, then replacing it with the new keys might be a smart idea.
That's my opinion but I don't have any facts to back it up.

 

Here's what I found. So the BCM or the PCM might be a good idea.The passive start system relies on the detection of a uniquely coded Smart key via Low Frequency (LF) antennas strategically situated within the vehicle. The antennas ensure the Smart key is always within the active transmission zone of the antennas wherever the Smart key is placed inside the vehicle. For this reason the orientation and positioning of the antennas is critical for the correct functioning of the system. The Smart key also operates the passive entry system.

For additional information, refer to: Handles, Locks, Latches and Entry Systems (501- 14, Description and Operation).

The system provides a secure interface between the Body Control Module/Gateway Module (BCM/GWM) Assembly and the Powertrain Control Module (PCM) to prevent unauthorized starting of the engine. This is achieved by immobilization of the engine crank system and the fuel system, using encoded data exchange between the Smart key and multiple control modules.

Engine starting is initiated when the encoded data exchange between the Smart key and the control modules is verified. The engine management system will then allow engine crank and fueling when an authorization data message is received from the BCM /GWM.

The engine can be started by pressing the Stop/Start switch when 'Park' position is selected and the brake pedal is pressed.

 

I can't believe they can't just flash your existing PCM; shouldn't have to physically replace it. Sounds scandalicious.

 

I’m surprised they can’t just wipe all existing paired keys and then just pair the new ones.
JLR must have implemented the security in some funky way...

 

When they rekey new keys into the system all old keys are erased. You have to physically have the new keys present and the old keys are erased if not present. So there isn't an issue with lost keys still working

Usually they can just rekey with new keys. But for added security they at some point changed it so you have to replace the key module along with the keys - think the intent was to stop someone keying a new key alongside your existing one without you knowing. But I think they stopped that again as it was crazy expensive to replace 2 keys and module

Anyway - if the dealer is paying then let them replace module if they want. As long as you get two keys that work you're all set!