View previous topic :: View next topic Author Tickalong Surf Site Member
Message Posted: Mon Oct 08, 2007 2:58 am
Post subject: TPS - WHAT YOU NEED TO KNOW
This information is good for the 2L-TE. In case there are any variations it applies to models where the TPS is mounted opposite the throttle quadrant on the inlet manifold. Joined: 10 Aug 2007 Posts: 83
TPS – Throttle Position Sensor. Part No. 89452-12040 Cost new - $180 (Toyota) Cost second hand – up to $90 (Scrappy) The Surf’s TPS is a quality bit of kit. No bakelite and carbon here. The resistance tracks are etched onto a ceramic/glass disk and the one I looked at showed no signs of wear even after it had done 250,000k. DON’T pull yours apart unless you are replacing it. It’s designed as a sealed unit and you’ll need brain surgeon skills to put it back together although it can be done.
The TPS has two outputs. One tells the ECU the throttle is closed and the other how wide open it is. The TPS is one of the sensors the ECU uses to determine how much fuel to inject. It also helps determine when to shift gear on the auto models. Correct setting. To set up the TPS you need to connect a multimeter set to resistance or continuity test mode, across the IDL and E2 terminals (see diagram). The best way to achieve this is to use 2 jumper wires with small crocodile clips on each end. Remove the plug and connect one end of the jumpers to each of the 2 most right hand pins as you look at the TPS from the front of the car. Connect the other ends to the meter probes. Then… 1. Slacken off the two locking screws and rotate the TPS clockwise as far as it will go. Confirm you have a closed circuit (reading in low ohms). 2. Insert a 0.85mm feeler gauge between the throttle stop screw and the throttle quadrant stop. 3. Slowly rotate the TPS anticlockwise until the meter registers the point the circuit is broken. 4. Tighten the locking screws at this position and confirm the switch is open at 0.85mm and closed with a 0.5mm feeler gauge inserted. Your TPS is now set correctly. Bench testing. Confirms TPS performs to spec. 1. Connect a multimeter across VTA and E2. Rotate the actuator checking there is a smooth increase in resistance within specs (see diagram below). 2. Connect a multimeter across IDL and E2. Rotate the actuator checking the meter reading goes from closed to open circuit within the first few degrees of rotation. 3. Connect a multimeter across +5v and E2 to conform it is within spec (see diagram below) Note: Because of the way the TPS works it is not required to be manufactured to close tolerance and there is some variation in the resistance between units as shown in the chart below. The important thing is during the transition from closed to fully open throttle, the change in resistance is smooth. There should be no position were the meter to ‘hunts’ (continual fluctuations) for a reading. In car testing for auto. Confirms TPS is functioning – TPS signals are reaching ECU – ECT ECU output. 1. Locate E1 and TT in the diagnostic port (see diagram below). 2. Connect a multimeter set to read DC volts 0-24volt range across E1 and TT. 3. Turn the ignition on. (don’t start the engine). 4. Rotate the throttle quadrant to the fully open position. The meter should read 7-8volts. 5. Slowly rotate the throttle quadrant back towards closed. The meter should show the voltage stepping down smoothly in 1volt increments.
