Code 51
 

I know there are a few of these threads around and i hate to cluter up the threads but i just got code 51 about 2 weeks ago. car was running fine but now the idle sits about 1,200-1,500 i cleaned the sencor whitch electrical parts cleaner and it helped for about a day but im still geting the code, i know i should replace the sencor but is there any aftermarket one that is a bit cheaper priced than one at advanced auto that will not compromise anything. my biggest concern is that since it idles higher i can let it spool down for a few minits but its still higher rpms than i would like to turn the car off at, dont want to prematurly wear the turbo bearings down

While im in there is there anyother part that afects my idel i should replace and or clean

How did you clean the sensor? It's a sealed unit.

The TPS is a wear component and really should be replaced every 75K to 100K mi. The AFM, and ISCV will also affect your idle as will a vacuum leak.

Oil bearing turbos generally don't move much at all at anywhere close to idle speeds, you're not hurting anything by turning the car off from a 1,200RPM idle. I suppose one might even argue it to be beneficial as you're powering down with a significantly higher oil pressure than would be the case otherwise.

cleaning wise i couldent do much because like you said i found out it was sealed so i made shure there wasent any debirs or corrosion on the spring,

i dont belive is a vacume leak because i checked all the hoses to see if there properly conected and in good shape, i think im gona end up having to buy a new one, its 75$ but if its a wear item i guss its just its time. now whith this replaced i should stop geting code 51 and idle correctly right?

As long as it's properly calibrated and the code isn't due to the A/C circuit then yes, the code 51 should go away.

i dident toutch any of the screws on the throtle body or asembly and it was ideling fine untill this code came up, so i shouldent need to recalibrate right?

Pull it and test it with a meter. If it passes then it needs to be calibrated when reinstalled. Do note that if you press the throttle or turn on the A/C when in the diagnostic mode you'll get a code 51.

when u say test it what am i looking for voltadge,ohms?
i usualy use a glow pen to see if its geting current but i also have a full voltmeter

Easiest to use a continuity tester (a function most multimeters have) to test the IDL switch. You should have full continuity at rest and then when the interface tabs are ever so slightly rotated you should have zero continuity (resistance = infinity).

You're testing pins E2 and IDL.

EDIT:
Here's the TSRM info on testing the TPS while on the car: http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=101

Take it off the car to test the IDL switch if you're not getting any continuity when at rest with the positioning screws loosened.

ok thanks this is a GREAT help maby even helpfull enought to go to FAQ

just concluding this thread. i just installed the new TPS, the car runs great not, the code is gone im supprisingly geting a little more miladge which is always an extra, and a bit more responsive

I have a question on this too. I have the original sensor and the car has 186xxx milea on chassis so most likely i should replace it? I checked the ohms and i was getting 1500-1600 i couldnt get it anywhere near 1 or OL

i just changed the origonal one which is at 135k miles and it was crap. the spring dident really have much force it wasent performing properly, yours being more miladge is probably worse off. I would replace it, for 70$ its not a bad investment

The thing with the TPS is that it's a potentiometer with resistance material laid down on a wafer in a steadily increasing density. A bad TPS may read fine as far as the resistance measure at the top and bottom but as the material wears down it wears down in between those extremes the most. The most effective way to measure it is to bench test it and test that the voltage output at pin VTA is linear and consistent from .48v to ~4.85v.

The TPS like the N/A's VAFM is a wear component which sees a lot of action. Replacing it every 75,000 to 100,000 miles is not excessive... if you don't want to, or are unable to, test it thoroughly.