ABOUT DAST SYSTEM

[usproauto]

Hello everyone, I have a 2015 Infiniti Q50 Hybrid. the car came in first with no codes at at all. Just had airbag issue and we took care of it. But the steering was hard when you turn. We decided first to do calibration since there were no codes at all. When we did the calibration we went to EPS/DAST3 and put the car on the lift and started the MODE1 calibration it went good and then started MODE2 and it failed(after some searching i knew that I did the calibration wrong and now it won't let me do the calibration at all so i can do it the right way) and it give us codes:
ABS: DAST1: DAST2:
C1138 4WAS CIRCUIT C13E9 BOOTING ANGLE PROCESSING C13EB BOOTING ANGLE PROCESSING
C1A70 BRAKE CONTROL SYSTEM C13EB BOOTING ANGLE PROCESSING C13F0 INCOMP DAST CALIBRATION
C1A75 STEERING SYSTEM

When you clear codes all goes away except the ABS codes and once you start the car and move the steering all the rest codes comeback again.

what was checked:
power and ground and CAN all good for both DAST1 and DAST2.
When i go to live data I see FLEXRAY COMM all normal which mean FLEXRAY between all the modules EPS/DAST3 and DAST1 and DAST2 are good.
Also on the live data I see the BACKUP CIRCUIT A, B STATUS: STAT2(which mean is normal) only on DAST1 shows stat1 on both. The EPS/DAST3 and DAST2 their BACKUP signal 1 is (4.2v) and BACKUP signal 2 (2.1v). which is good. On DAST 1 which shows STAT1 and BACKUP signal 1 is 2.1v(which is bad) and BACKUP signal 2 (2.1v(good))

we bought another DAST1 which is the one connected on the right side behind bumper(passenger side) because if you disconnect it the back signal on the wire shows BACKUP signal 1 is 4.2v(which is good) and BACKUP signal 2 is 2.1v. My conclusion something is shorting DAST1 computer or the computer it self is bad. We already bought another module used with same exact part number and program it and it's still the same exact thing.

all backup signal wires between all three modules were checked and they are totally fine no damage.
Does anyone know what's the backup circuit for and what does it connect to or which sensors it checks? is the issue with the steering rack itself or where exactly? I will be attaching pictures of live data and codes as well

Thank you

[VStar650CL]

C13E9 and C13EB both mean mean the DAST's can't initialize correctly. The current FSM has some different procedures from the ones in here, there's a reset you can try by twiddling the ignition. If you want to post your email, I can send you a PDF of the FSM section for C13E9.

Otherwise, the system details can be found here:
https://www.nicoclub.com/service-manual ... %2Fstc.pdf