3230 Views 5 Replies Latest reply: 2017-03-06 15:16:52
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Level 2
(16) points
Long story short....
VSC AGAIN and AGAIN and now some codes – anyone ever figured this out?
Well after 8 years I’ve gone and bought a decent scanner/code reader – Autel DS708 and plugged into our 2003 GS300. For 95% of the time we have owned this the VSC/ABS lights have been on – thought we sorted it out 3 times 1) brake fluid reservoir was 5mm low 2) the bank 2 sensor 2 oxy heater/sensor was changed 3) reset the Yaw rate sensor (even made an OBD plug up specially to make this easier as the generic code readers have been known to trigger these lights on Toyotas for some reason – they all worked for a little bit then back again. The lights normally illuminate after 1-2 mts of car movement.
Now we also have the TIS Dealer software (disappointingly very basic old thing though) and both systems show NO OBD or fault codes anywhere. The abs sensors all read fine during driving.
Having gone deeper into the new scanners system I go to the ABS section where the Yaw sensor can be reset and the utility allowed another fault scan and the pictures below show an alarming amount of faults!!! Physically impossible for them to be real – it also allows you to clear faults at this menu but….it does not clear them – they remain in the system! Is it possible that’s where the real culprit is living????
Now before you ask – every mechanical an electrical component on this car HAS been changed from the complete drivetrain (engine/box/diff/exhaust) to everything under the hood – all except the ECU – and despite the mind boggling cost – the exact same problem exists – by simple conclusion (bearing in mind the donor car drove with ZERO faults) is that the fault remains in the ECU - ????
Now after years of probably reading every post on the subject surely someone must have got the bottom of this cr*p system that even turns off the VSC when the cat heater senor goes faulty??? WHY??? – it’s not part of the traction/braking circuit?
Is there maybe a bypass for this??
Help….because if these do not sort the problem I am going to have to scrap this amazing motor – sometimes you have to know when to let go…..
there are 3 pics but system only uploads 1?file: 2.JPG -
Level 10
(7578) points
Well I would inspect the ABS tone wheels for cracks , check the pid for master cylinder pressure switch changes stepping on brake. Check what degrees the Yaw sensor and steering angle pid shows on level ground with steering wheel centered. -
Level 2
(16) points
All checked and all within reason specs.
Is this all the response we can expect on the forum? 1 good reply from 1 good member? -
Level 7
(817) points
am so glad this is the short version of the story, can't even imagine what the long one may look like lol. anyway VSC is a lot more complicated than you may think specially on this older Toyota vehicles with such slow computer/modules. when I say Toyota I mean Toyota/lexus/scion vehicles. vsc is not just disable by an abs malfunction but rather anything pertaining to powertrain, engine, transmission and abs. VSC is a traction control/stability control part of the abs system and very sensitive to any changes, the reason this light is almost always on. any sensor out of range in engine, transmission and abs the VSC light will come on and without having any trouble codes related to engine, tranny and abs. your powertrain modules are too slow to pick up any small glitch in the system but vsc does. late model Toyotas don't have that issue as much. I have had many of this problems in the past and let me tell you it is not an easy thing to diagnose. there are many cases when even the throttle is disable and goes into limp mode. I have had a vsc on because of a o2sensor, low brake fluid, bad tps or out of range, one wheel speed sensor reading 2 mph faster or slower than the other, bad abs module, bad ecm/pcm, bad wiring connection, bad brake s/w, bad brake pressure s/w, out of range coolant sensor and it goes on and on. traction/stability can not be controlled if there is any issue at all in the powertrain system. I had a 2001 sequolla that drove me nuts. this is my short version of the story too. good luck with that, now you have 2 more modules to look into so I know your next post is going to be much longer. -
Level 2
(16) points
Spike - ditto to everything you just listed! Scariest part is when in traffic and limp mode kicks in with literally no throttle input over 5mph! Try that on a highway for an ass gripper! We went one better....got the so-called Head of Tech Dev for Denso out for 6 hours - that took some doing - and was as much use as a chocolate teapot! End result was nothing - guy did not have a clue.
Main reason for the post was to find out why we cannot clear the C codes from the system with the DS unit? Could it be the car is fine (ha!) and as these codes are still in the eu they will keep flagging the vsc?
Other question is...can the vsc be bypassed or rigged to flash on with ignition then off again so we can at least get it though the Test! -
Level 7
(817) points
I will try disconnecting both battery terminal and touch them together to clear capacitors and do a real memory reset, something could be set it and not clearing when you erase codes. also with key off jump/bypass pin 4 and 12, turn key on for 3 minutes then key off, remove jumper. after everything is reset you could turn track off if you want to disable it but I don't recommend it, specially if some one with not much driving experience is going to get behind the wheel of that car since there isn't going be traction/skid control available. if you are the only one that drives that vehicle and can control the brakes pretty good then yes you could disable track. I have seen people installed switches to cut the ground side of the system but I don't know how helpful either of this ideas/hacks will help you. I will try diagnosing this vehicle one more time, see if you can find anything wrong with it. do e real good check on the whole powertrain system, use a scope if you must to check glitches etc. do smoke test to verify there is no vacuum leaks or evap leaks cause even a bad gas cap will turn that light on. check tps, both signals to make sure they are within specs and make sure that tps and other sensors you replace did not come from auto zone, discount auto parts etc. this Chinese made sensors are braking more cars than they fix. but don't replace them just based on that, they could be fine, but scope them, they could be off or have glitches, a scanner and onboard ecus will never see that. if a scope is not available check with a voltmeter but in hertz/frequency mode, its about the same as a scope but without the graphics patterns, well not really the same but it will help a bit more. to be completely honest with you this is sometimes super hard to find and it will most likely take you or anybody else a lot of times but at the end if you can find it at least you will have the satisfaction that you were able to. Toyotas are super good cars and trucks and I will not get rid of it, they are worthy of fixing anything . good luck
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