Dear Jag-friends!

have here a heavy one. Symptons:

1. Key. Transmitter.
unlocking the dors with key transmitter FOB only opens the driver side door. No reaktion when trying to lock the doors with the FOB. The driver side door can be locked with the key using the door lock. Only the driver side door then looks the other doors do not follow.

2. Trunk does not close properly.
The electrical engagement of the lock does not work. Trunk must be opened with using the key with the trunk lock

3. Steering lock does not unlock when the key is inserted
Naturally the car does not start since it does not unlock. Looks like a problem with the PATS (passiv anti theft system). The transponder of te key might not beread properly.

4. JLR/SSD shows the following related issues:
U1262 – SCP (J1850) Communication Bus Fault

5. JLR/SSD shows the following not related issues:
DSM: B1940-25, B1940-26, B1940-29, B1940-31
FEM: B2196, B1500, B2035
IP: U2195
PAM: B1299

Interpretations:

It looks to me that for some reason the SCP bus communikation is faulty. This prevents the steering lock to be unlocked. In consequence the car das not start because of the PATS.

What to do?

I have found the following link that explains the U1262: https://www.troublecodes.net/ucodes/u1262/

Did the pinpoint tests on the SCP using the Data Link connector. The SCP+ and the SCP- have no shortcut to groud or power. SCP+ is on 0V. SCP- is on 5V. The Resistance between SCP+ and ground is 115Ohm.

In other treads I have rad that a faulty door lock can kill the SCP bus communication (S-Type).

Your recommendation to tackle this problem?

Thanks in advance and best regards,
Martin

 

Hello,

I checked the CAN BUS and the SCP BUS with an oscilloscope. The graphs look good to me

CAN Bus
1. Ignition Key at position 0. Both CAN high and CAN low are at 1,38V
2. Ignition Key at position II. Both CAN low and CAN high recisive are at 2,53V. CAN high doinat ist at 3,5V. CAN low dominant ist at 1,5V

SCPBus
1. Ignition Key at position 0. SCP+ is a 0V. SCP- is at 5 Volt.
2. Ignition Key at position II. Does the signal looks good? I don't know how a good signal hast to look?

Regards,
Martin

 

Here the pictures of the oscilloscope meassurements:

 

Do you mean that the key won't turn in steering lock at all, not even to the first (aux) position ?