C4 Spacetourer 1.5 HDi 2020 Engine won’t start / “No communication with electronic key reader”

[Antonij]

Hi everyone!
This post is about a no-start issue with my Citroën C4 Spacetourer 1.5 HDi, 2020.
I’ve been reading this forum for a while to find information about my car — it’s been really helpful. Many thanks to all the members for sharing their knowledge!
Now I have a problem with my car and I’d really appreciate your help.
At some point the car didn’t start — the battery was completely dead. I replaced it with a new one, and had it initialized at a service center.
After that, I made a couple more trips without any issues. But the next day, after parking for about five minutes, and the engine refused to start again. The starter turns, but the engine doesn’t fire up.
Diagbox, among several other fault codes, shows the message: “Electronic key reader Communication error'

However, my car doesn’t have the separate electronic key reader module (8239)— the key reader coil (10C2) is connected directly to the BSI.
The remote key fob still locks and unlocks the car, and it allows me to switch on the ignition (without starting the engine).
I’ve uploaded a video showing the starting process.
Can anyone explain what these immobilizer parameters mean?



It says that two keys are programmed, but when I bought the car, I only received one key.
Thanks in advance for your help!

[mickthemaverick]

It would seem that the car is confused. Are you trying it with the key fob in your pocket or somewhere else?

[Antonij]

I switch on the ignition and try to start the car with the key fob inserted into the key reader, just like I always do.
It’s exactly like in this picture (taken from the internet).

If pull the key all the way out of the slot, the car immediately stops detecting it.
I'd like to note that in Diagbox, under the immobilizer tab, the presence of the inserted key is detected — but the key itself is not recognized

And why, when press the start button, when with the ignition on, there is a command to start the engine and the starter begins to rotate, so many parameters go into "failure" value?

[RichardW]

I think this might not be an immobiliser issue. What happens if you try and crank it without the key in? Might be worth a look in the oil filler to check that the cam is still going round...

[Antonij]

I think this might not be an immobiliser issue. What happens if you try and crank it without the key in? Might be worth a look in the oil filler to check that the cam is still going round...

Yes, the camshaft rotates (I opened the oil filler cap, set up the phone to shoot video, and started the engine as usual with the button), the diagbox displays shaft synchronization - OK. The rail pressure is more than 400 bar, the LED connected to the injector flashes when the starter turns the engine.
But the immobilizer parameters are very strange, why the key is not recognized....