First it really helps if you let us know what model of Q50 you have, there is 2 generations of car and there is typically
seperate ABS systems for RWD and AWD cars so it's important to give us your basic information. Hah
Look at the SM a U1000-01 code it appears to be a generic communication error, if your able
to clear the Code on your scan tool do so and see if it comes back.
If not you'll need to bring the car in and have the connections inspected and or possibly the Control Module replaced.
I don't recommend you attempt replacement yourself as it appears to require a CONSULT tool and a backup/export of your configurations
before the old unit it removed.
Definitely would help if the OP as well as everyone else here put relevant car information in their signature (year, model, options, mods) in order for us to assist in answering questions.
It doesn't appear to me that there are separate ABS systems for RWD and AWD. The FSM shows only one for both.
The C1140 DTC is indicating there is/was a malfunction detected in the actuator relay in the ABS actuator and electric control unit. That DTC can be classified as PAST or CRNT. This is determined with a CONSULT scan tool. If after running the DTC confirmation procedure, the CONSULT displays PAST, then the DTC is cleared and no further action is necessary as it was a temporary problem. If CRNT is displayed then the problem still exists and could be due to:
Faulty or loose harness or connector
ABS actuator and electric control unit
ABS actuator and electric control unit power supply system
There are fusible links for the ABS actuator and electric control unit in the Fuse and Fusible Link Box. They are: Fusible Link "L" 30A and Fusible Link "N" 50A. I don't think that's the problem though and I doubt it's the battery either. See diagram below:
If the fusible links are ok, then the ABS actuator and electric control unit's power supply and ground circuit need to be checked as well as the pin terminals on the harness connectors. If there's no problem there then it's likely the ABS actuator and electric control unit needs to be replaced.
Don't muck around with the ABS system. This is not shadetree mechanic work and brake control system maintenance should be left to qualified mechanics. It requires a CONSULT scan tool that the service department uses for diagnostic purposes. You can inspect the connectors for something obvious but I doubt you'll find anything. The ABS actuator and electric control unit is located on the right next to the brake fluid reservoir and master cylinder. See diagram below (#12):
The U1000 DTC indicates that that there was a communication interruption in the CAN gateway of greater than 2 seconds. This could have been temporary or it is indicating a reoccurring communication problem in the CAN highway if it doesn't clear with an ignition cycle. Again, a CONSULT scan tool is necessary to properly diagnose the problem.