Jump to content
The mkiv Supra Owners Club

VVTi Fly-by-wire throttle position sensor calibration


Alex

Recommended Posts

I've got an issue with my new car...

 

Basically when I'm driving at low speed the engine check light can come on and the throttle stops working!

 

It still idles fine so the Idle control is not at fault.

But I lose the Fly-by-wire controlled part of the throttle (about 80% of the travel does nothing and the last 20% is a quite uncontrollable :eek: as it then does the full range of throttle position in the last inch of pedal travel!

 

Anyway, I was told about this before I bought her, it's down to the calibration of the Throttle Sensor on the throttle body. The unit has been replaced and now throw's a wobbly - though less of one than it used to do.

 

So, does it need calibrating - if so how? Do I just need to reset the ECU (which couldn't hurt anyway)? I tried the full electrics, engine off, hold the throttle flat to the floor for 2mins calibration trick and that didn't help. Should I try that again after an ECU reset...the ex owner mentioned something about using a multimeter to calibrate it! ???

 

Thoughts?

 

TIA

Link to comment
Share on other sites

Originally posted by dude

Alex ,had this on a Lexus GS300 it was the TPS , cost about £197 + vat .

 

Dude:flame Dev

 

It's been replaced already...I have the old one in the boot! I've noticed there is some adjustment available in the sensors mounting...could this be the issue? It's possible to mount it through 4-6degrees...

Link to comment
Share on other sites

Originally posted by Alex Holdroyd

It's been replaced already...I have the old one in the boot! I've noticed there is some adjustment available in the sensors mounting...could this be the issue? It's possible to mount it through 4-6degrees...

 

Alex yes IMO it will make a lot of difference , you can prob set it correctly with a multimeter , on the older cars the TRAC one is the same an d a small movement puts the warning light on .

 

Dude:flame Dev

Link to comment
Share on other sites

***UPDATE***

 

Throttle position sensor:

 

When not working:

Pin 1 = +5v

Pin 4 = gnd

Pin 2 - 0.66v closed throttle, only changes when the throttle is opened enough to mechanically move

Pin 3 - 2.36v @ closed, only changes when the throttle is opened enough to mechanically move

 

When working:

Pin 1 = +5v

Pin 4 = gnd

Pin 2 = 0.63v closed to 3.75v open

Pin 3 = 2.36v closed to 5v at mechanical link

 

Disconnecting either the TPS cable or the other one causes the failsafe mode. The engine doesn't have to be running for the problem to happen, no bumps or jolts or loose wires either.

 

Terry can you please check this against yours?

Also, on full electrics/engine off do you get any noise out of the throttle area? I'm getting a buzz/hum and a when you push the throttle open it clicks as it opens....

 

Ideas please! How do you get the error codes out of a VVTi? As it seems to be disabling the Fly-By-Wire and going into a failsafe/limp home mode.

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.