Car had throttle body issues, then transmission, now throttle again

Saturn ion 2007 2.2l eco Tec gm hunk of crap

Was getting error Throttle Position Sensors 1-2 Not Plausible 5 weeks ago, tried cleaning the unit, worked for 30 miles, had to replace the unit.

3 weeks ago had pressure control solenoid make my car go into limp, crossed my fingers it was dirty trans fluid and not the actual part. Did a flush and she was driving better.

Everything smooth for few weeks and today throttle body not plausible again.

I’m wondering are these problems are connected some how, and secondly since throttle and sensor was replaced is it usually the gm crappy pedal or the gm crappy ECM?

I’m ready to burn more money on parts! I love Saturns!

How about given us the crappy Code that your crappy car gave you… :wink:


This may be your problem…

SB-10028831-1253.pdf (

If that 16 year old “hunk of crap” ran decently until just recently, I submit that it isn’t really “crap”. And, I think that the Service Bulletin posted by weekend warrior is worth considering as a possible solution to the problem.

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That’s lovely lol, so it’s recommending me to multimeter the connection to check for proper voltage and if good, wrap it up from future leaks and seal the area around it as well?

No my first saturn was problem every month from 18-22 years old

Decided to double down on friends $500 offer because he just got a new car and didn’t need his saturn anymore. Probably 6-7th repair this year.

Meanwhile my buddy jack his damn Buick from his grandpa literally fixed brakes once since highschool and nothing since😂 I’m telling you man Saturns are out of business for a reason

Crappy p1811 will be for the PC solenoid 1-2 acting funny

And believe throttle not plausible was pulling P2135

Any chance I don’t have transmission problem at all and the bad throttle body connection randomly gave me bad error code few weeks ago?

When you did the fluid change, did you just do a drain and fill or did you take it to a shop and have it put on a flush machine.

If you DIY, did you do a reverse slam. This is a common procedure for Saturns and all it is is setting the parking brake and put it in reverse for 10 min to half hour. A couple of those circuits gunk up from lack of use and the reverse slam cleans them out.

Is your throttle fly-by-wire? If cable operated, did you try to set the idle with the throttle stop screw? If so, that could be your problem. The throttle stop screw is not an idle adjustment, it is only there to keep the butterfly valve from jamming in the throttle bore.

Do you have a scan tool that will display both the accelerator pedal position and the throttle valve position? It seems like if you could watch those two numbers while you moved the throttle pedal, you’d get to the bottom of it pretty quickly. Position sensors often use a variable resistor to sense the angle of a shaft, both the shaft that rotates when you press on the gas pedal, and the shaft that rotates to move the throttle valve. With time & use, that sort of variable resistance sensor often tend a to develop dead spots, so at certain angles the resistance is out of whack. Have you ever had an older radio with a volume control knob that didn’t vary the volume smoothly as you turned the knob? Same thing. I expect you need to test all of those sensors to determine if their resistance varies smoothly and consistently as the shaft rotates.

Could I multimeter for dead spots? Or is getting a full scanner best option vs part chucking

No I have a basic cheap ob2 for basically just codes.

Trans flush i put it in every gear for about 5 minutes each, then went back up and repeated.

For throttle it’s electronic with sensor on it. Wasn’t any wires around it.

On modern cars like yours, the replace this, replace that and see what happens usually isn’t very effective. Easy to run out of money before running out of ideas what to replace next. The scan tool method is better, b/c it not only tests the sensor, but the electronics that reads the sensor. Do you have access to the vehicle’s pertinent service data? Even an aftermarket manual like Haynes or Chiltons might have a diy’er test for those positions sensors. From what I can tell the sensors are powered with a 5 volt reference signal, and may not be bench-testable unless they are powered up, best done using a scan tool to read their outputs during a “sweep test”. Best bet probably is to either secure the needed scan tool, or hire a shop that has it already. Once you know what the problem is you can always replace the part(s) yourself if you want.

Note that the problem could be something entirely different, like the throttle valve is sticking inside the throttle body.

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I would look hard into the Accelerator Pedal Position (APP) assembly (gas pedal), it has it’s own TPS and an off idle sensor IIRC, if it acts up, it can enter limp home mode… Also since the transmission no longer has a mechanical link for the PR valve, it gets it’s info from the throttle pedal (at least some of it) which can cause shifting issues, or possible limp home mode to keep from burning the transmission up…
The P2135 is a a/b voltage Correlation issue between the throttle body and the gas pedal…

Jokes on you. I don’t even know what a trottle body is. Lol…

That’s no surprise, with some of the answers you give, you don’t know much about anything car related.


Appreciate the link.

I think the ob2 will arrive today before I try & order part #2. I’ll see if I can post the live data after.

But not 100% sure what to look for besides the numbers need to correlate. I assume if accelerator position is wack, it’ll be the APP replacement. If both are messed up and goes wonky I assume that’ll point to electrical problem.

And gonna assume tps/throttle itself is fine since that was replaced. Tho not impossible.

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Hey man, found
absolute throttle body position (no letters)
throttle body postion B and D and E
Relative throttle position

Which of these 5 should i select or all the above?

No experience with your car or its diagnostics but I’d guess the ATP (first in the list, which I’d guess is “A”) and its “B” version are two separate sensors measuring the same thing (the throttle butterfly valve inside the throttle body), so they should more or less be the same as you move the accel pedal through its range. They seem pretty close, but no idea if they are as close as they are spec’d for. It appears the accel pedal also has two sensors, D & E, which should probably match each other and the throttle positions through the entire range. E appears to be a problem, isn’t matching either D or the two throttle valve positions. It’s possible however that E is correct and the other 3 are the problem. An argument could be made for that theory b/c the commanded throttle position is close too E. Maybe somebody here with this sort of experience will chime in. In any event it appears you are getting close to a diagnosis.

Uploaded short for future help of an actual acceleration + live graph

Yellow line = throttle actuator control
Dark blue = absolute throttle position
Purple = position B
Light blue = position d

Couldn’t add position E because I can only select 4. Not sure what ones were needed I assume all 5

Thank you for guiding me this far.

Edit: is their a chance since I cleared the code, and it’s driving without limp that it’s not gonna be easy to tell what’s wrong?

So with throttle positions being 2% off

today I tested the APP sensor and APP indicated angle Both of those roughly 2.8% off as well.

Does app sensor and app angel need to match 100% or does throttle positions have to 100% match?

I haven’t been able to get the car to limp out or check engine yet so. Maybe the problem won’t show til it happens.