2003 throttle controller not available from Toyota

This is where a good scan tool or inexpensive lab scope comes into play. You will be able to see TPS in real time. You should have a check engine light on with codes though. You could always test with multimeter but the sampling rate is too low to show really small dropouts which is where the lab scope comes in. If there is no signal whatsoever you need to check the integrity of the wiring and make sure your powers and grounds are good.

 

Problem with a good scan tool is it wont pickup the Accel pedal position switch because it doesn't know your trying top move the pedal. The TPS is not the problem. I was able to catch it acting up using the Toyota TIS software on a laptop logging data while driving. Took a couple hours of driving to catch it. If you check the link in my above post you can see a screenshot of where it acted up.

 

Is this diagnostic software available anywhere online? Also do you know a link for the learning process? I assume that will be required when I replace the throttle body and associated sensors. Thanks!

 

Software was an ebay deal. Idle relearn, I just removed battery cable for 30min then went and drove it awhile.

 

Ok, cool, I was hoping the battery reset would do it. I'll search for the software. That sounds useful.

 

@mechanicjon I'm wondering if the APPS is the reason behind my random idle rpms? I may have boogered it up years ago by cleaning the TB butterfly and disrupted the delicate sensor inside

goal is to pull stuff off towards the end of august and work on rear frame and suspension. possibly replace intake runner gaskets (fighting random misfire on cyl 5: plug, swap coil, new injectors, nothing fixed it so far)

 

It's possible but the sensor is actually a little more robust then you think. Have you run a leak down test on #5 cylinder? Checked valve lash?

 

not yet, time constraints and lack of tools.

 

May I ask why you inquired about the #5 leak down. My 5VZ-FE #5 cylinder leak down has been 25%, and all the other cylinders are around 6% since I've owned the truck.
I feel the problem is with the rings. A little oil brings the leak down and compression back up.
I not too concerned because the engine run great, uses no oil and the MPG is as expected. When I did the head gaskets the #5 bore had no scoring and still has cross hatch from top to bottom.

Next oil change I am going to try a can of BG EPR. Thinking maybe it a stuck ring.

Any opinions?

 

It could be a stuck ring, a broken ring or for some reason the rings lost tension on that cylinder. Oil consumption is controled by the oil rings. It sounds like yours are okay. It's an issuse with the compression rings causing your high leakdown.

 

I would figure a broken ring would leave a scratch in the bore but have no experience to back that up...just hoping not
Do these engines have an issue with #5-cylinder compression? I've read a few times about low #5 cylinders.

 

Not that I'm aware of.

 

So replace the throttle body with the new APPS sensor on it, and that indeed fixed the problem. Truck is back to working normally. Thanks for the help and comments gang!

 

Update to original post. I removed the sensor and found the little “sweeper arm” on the inside to be stiff and have inconsistent resistance when I moved it with my finger. Sometime it didn’t return all the way. I sprayed WD-40 on the coil spring and moved the arm back and forth a few dozen times and it totally freed up. I reinstalled it and the truck has been running fine for about a month. The check engine light also went off.

 

Hold up. You were able to get inside the throttle cable APPS sensor ? Or did you open up the TPS on the back side of the throttle body?

 

When you take out the two screws that hold the sensor in place and remove it, you can see the spring and sweeper arm on the underside of the sensor.

 

That's the TPS sensor not the APPS sensor. The APPS sensor is held on with 4 screws.

 

I have been doing this for years. It has worked until recently. Not sure what to do now.

 

And apparently there are 2 different tps's for the 2003. Depends if your truck was made in the US or Japan. I found out by getting the one Napa said I needed.

 

Your truck's throttle wasn't acknowledging the gas peddle? Or what was it doing? Did the throttle body help your truck? I'm going through this right now. For years I've been pushing the gas pedal down for 100 times and driving for months without an issue. It's not working as good now. I have to try something else.