Slip control light flashing

[rider]

The slip control flashing amber light happened to me today. 

Having read a few threads it seems it is usually either the TPS or ECU that causes this phenomena. Turning the ignition off and on can often reset it apparently but that didn't work for me. It has stayed off after I disconnected and reconnected the battery. So at least I now know the slip control button is set to on.

I've ordered a new sold as genuine Toyota TPS, does anyone have the specs on setting this up properly on install as there is a few degrees of movement that will change the resistance reading generated by the sensor, particularly important for the idle apparently so best get it right. Also its not unheard of to strip the screw heads that secure the TPS onto the throttle body when taking the old one off, does anyone have any best practice tips on how to avoid this occurring and if it does occur, how to work around it.

Usually the TPS on cars have three prongs, the Supra has four. So if anyone knows which each does so I can check the feed voltage and output resistance. Also, why are there 4 connectors and not 3 - that'd be useful to know.

Other than this mishap, it was a fine Sunny Supra day.

[rider]

Found a testing write up by SJ off the Supraforums site so may as well add it in here for anyone looking for solutions on this site in the future. Any input on the other questions I raised will be gratefully received.

TPS Adjustment Procedure and Testing Procedure - Coming soon IAC Test Procedure

This is the Throttle Position Sensor Adjustment Procedure.

What you will need:
1. Multimeter or Ohm Meter
2. Screw Driver (Philips)
3. .65mm (.026 inch) Feeler Gauge
4. Other size feeler gauges listed below to verify tests.

Procedure:
1. Loosen the two screws holding the sensor on just enough so it can be turned. The Adjustment is very precise so just loosen the screw enough to turn the sensor.
2. Insert feeler gauge between the throttle stop screw and the stop lever.
3. Connect one tester probe to terminal IDL and the other to terminal E2. When looking at the TPS as it sits they are the two left connectors. Since we are simply checking for resistance it does not matter which probe end goes to which terminal.
4. Very slowly turn the sensor clockwise until the ohm meter deflects to 0L (no continuity) and then retighten both screws.
5. Recheck continuity between the terminals.
a. Insert a .54mm (.021 inch) feeler gauge between stop screw and stop level. You should see continuity.
b. Insert a .70mm (.028 inch) feeler gauge between stop screw and stop level. You should see no continuity.


Remember you are making tiny adjustments so it is very difficult to set the sensor in the correct place. You will probably need a few attempts to get it correct. Feeler Gauges are simply little pieces of metal that are precise thicknesses. All the ones needed are common in a set and you can get the set at sears are most tool stores. They are also very cheap.

EDIT: I was adjusting a TPS today and realized there was an important trick I left out of my procedure. After you have adjusted the TPS and have the correct resistance, you have to be very careful when tightening the screws that hold then sensor to the throttle body. I generally turn one 1/8 of a turn and then the other 1/8 of a turn and repeat going back and forth until the screws are tight. This will keep the TPS from moving and changing the setting ..... if you were just to tighten one and then the next and will throw off your adjustment and you will have to do it again...basically you want to tighten the screws as evenly as possible.


Testing Procedure for electrical specifications:

This is the procedure to make sure your TPS is fully adjusted and in working condition.

What you will need:
1. Ohm meter or multimeter
2. .016 inch and .019 inch feeler gauge

Procedure:
1. Make note of which terminal is which for future reference. When looking at the top of the TPS we will can Terminal 1 the very left terminal and Terminal 4 the far right terminal. Terminals 2 and 3 are in-between.
2. With throttle body closed: Connect ohm meter to terminal 1 and 3. Resistance will be between .34k and 6.30k ohms.
3. With .016 inch feeler gauge between stop screw and stop lever, measure resistance between terminal 1 and 2. Resistance should read under .5k ohms.
4. With .019 inch feeler gauge between stop screw and stop lever, measure resistance between terminal 1 and 2. Resistance should read under infinite aka open circuit.
5. With throttle body opened completely, connect terminal 1 and 3...resistance should read 2.4 - 11.2k ohms.
6. With throttle body opened completely, connect terminal 1 and 4...resistance should read 3.1 - 7.2k ohms.

Sorry I have no pictures but this should be detailed enough. Please let me know if something is not clear or any suggestions. Have fun doing what I do all day. 

 

TPS5.pdf TPS4.pdf TPS3.pdf TPS2.pdf TPS1.pdf

[Mike2JZ]

You should probably check what error codes you are getting before replacing TPS. It's usually ECU related rather than TPS, but you never know I guess. 

TPS has 4 wires. 5v, Signal Ground, TPS Signal & Idle Switch. Idle switch is active when throttle is closed. 

To avoid stripping the bolts holding TPS in place, use an impact screwdriver or just hammer a normal screwdriver onto the bolt first to shock the bolt and it will come loose easy. 

[rider]

Thanks for the input Mike, the error has cleared so I'll leave replacing the TPS until the error reappears and I can then check the code. Reading a bit further on the subject it can be the sub TPS as well. At least I can go ahead and check the open/closed resistance on the TPS and sub TPS are within spec at any time without awaiting a reoccurrence of the flashing light.

[rider]

As a cautionary note for anyone changing a TPS, after reading around the subject matter I did read in a thread on this site someone's comment that changing the TPS is no more than a five minute job. Maybe two screws and a clip undo/redo is a five minute job but I cannot believe setting up the closed and open position accurately is anything like a five minute job. Setting the TPS close position away from optimal can apparently cause anything from rough idle to incorrect running fuel ratio.