VSC & TRAC, is controlled ABS. The VSC & TRAC OFF with activation of ABS (braking the faster turning wheels). Can be activate by loose component's. Such as:
Sloppy Rack & Pinion bushing,
Loose/bad TREs
Bad ball joint(s)
Busted/bad sock(s)
AHC set to soft (low pressure)
Loose wheel bearing (commonly set off ABS)
Bad alignment.
The ABS system may activate, jerking steering. This can be due to a fault. Wherein, it may happens so fast, we don't see dash lights. This condition, doesn't happen much in a pure stock 03-07LX w/VGRS. It has been report a few times in modified (delete) AHC 03-07LX. I've not yet had the opportunity, to track down and correct the cause.
What I "now" (subject to change) believe. The the VGRS Rack & Pinion. Has a slightly different gears ratio, that's all. That using a non VGRS rack, will not damaging actuator. It "may" add a little strain resulting in heat, so "may" oversized tries. The Actuator "should" be able to handle, some extra strain that "may" be added. A very active actuator, where it changing gearing often rapidly, will also create heat. As I recall, without review: Speed, declaration, steering angle, braking, ABS, ect. all have effects on actuator, via CPU. Any of which having, may results a more active actuator (heat).
VGRA actuator is very robust and rarely fail. I've spoken with a few Lexus parts department, and learned: VGRS actuators are rarely ordered.
What will damage actuator, is impact to intermediate shaft(s in direction of actuator. This can be from an accident, with front end impact. By pounding on intermediate shaft(s) in direction of actuator. Very often a shop, while replacing R&P. Use an air hammer, pounding intermediate shaft in direction of actuator, to separate from R&P input shaft. A damaged actuator, may not engage or may just run hot. If heat exceeds limit. It goes into failsafe and locks, become like non VRGS gearing/steering. We do not get any dash lights when this happens. The actuator, during normal operation, may go in and out of failsafe to cool. We don't usually even notice.
VGRS not properly calibrated, may also create more heat. Over time, may also add to damage or damage actuator.
- Align vehicle, is a good first step. May be a must if alignment is off.
- Zero point calibration.
- In tech stream, ACH date. Clear any DTC & Rec. You need DTC 0 and all Unrec (REC, is the one missed by most).
- After driving "Straight Angle Valid flag" ahead & turns flag Inval, should be Valid.
- Center street wheel, by following steps in tech stream. (This may also give Straight Angle Valid flag, so try before step 4, to save time)
- Turn engine on, turn steering wheel LH to stop, than count rotations while turning to RH stop. We get ~2.4 turns, which indicates actuator engaged. Return the center, then turn engine off.
- Start engine, turn steering wheel 90 degrees to LH, return to center. Then 90 degrees to RH and back to center. Keep steering wheel centered 3 sec or more, then turn engine off.
- Start engine. While turning slowly to the LH from steering wheel center position, stop engine (IG to ACC) and keep turning for 3 second after engine off. Repeat 15 times.
I like to then drive, see all date is good (No DTC, invalid flags or Rec). The redo zero point again, when all done. We need wheels straight ahead, steering wheel centered and on level ground. While zero point calibrating.
See: 1 Invalid, 1 Rec & 1 DTC each displayed. All need correcting before calibration.