DTC P1630: Communication Error from VSC to ECM: Procedure

WARNING: This page is about a different car, the 2012 Lexus GX 460. However, it is still accessible from the selected car via links, so may be relevant.

REPLACE MASTER CYLINDER SOLENOID (SKID CONTROL ECU)
1. Replace the master cylinder solenoid (skid control ECU). Refer to DISASSEMBLY .
NEXT: Go to next step
CHECK FOR DTC
1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
2. Perform the following to make sure the DTC detection conditions are met.
  HINT:
  
  If the detection conditions are not met, the system cannot detect the malfunction.
  1. Drive the vehicle at a speed of 50 km/h (30 mph) or more.
  2. Turn the cruise control switch on.
3. Check for DTCs. Refer to DTC CHECK / CLEAR .
  OK
  
  DTC P1630 is not output.
NG → See step 3

OK → END (MASTER CYLINDER SOLENOID [SKID CONTROL ECU] IS DEFECTIVE)
REPLACE ECM. Refer to REMOVAL