Codes P2101 and P1516, engine goes into reduced power?

Tiny
BCLIEN+CAR
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  • 2017 BUICK ENCORE
  • 1.4L
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 110,000 MILES
Engine goes into reduced power mode with P2101 and P1516 codes. After clearing codes, the engine will start, and I can press the gas pedal to increase RMPs a bit. But after a bit it will go into reduced power. The pedal will do absolutely nothing at that point. No increase in RPMs at all. It will only idle. I replaced the throttle body with a scrap yard throttle body, same symptoms. I put back in the original throttle body. Same symptoms. Any suggestions or questions or something to try?
Saturday, February 15th, 2025 AT 8:44 AM

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Tiny
AL514
  • MECHANIC
  • 5,132 POSTS
Hello, if you have tried another throttle body and have the same exact issue, its most likely going to be a wiring problem or possibly a failed ECM, but we will go with the wiring issue to begin with, do you have a multimeter to do some testing with?
And with the key Off, can you see if the throttle plates are fully closed with the air intake boot off? Do not put your figures anywhere near the throttle plates.
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Sunday, February 16th, 2025 AT 8:43 AM
Tiny
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I do have a multimeter. I did test and verified I had 5 volts coming from the ECM but that is all I did. Was not sure how to do anything beyond that. I will look to see if the throttle plates are fully closed with the key off. But shouldn't they be if the key is off? I'll do that now.
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Sunday, February 16th, 2025 AT 8:52 AM
Tiny
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Yes they should be. But that's one of the testing inspection steps, I'll post the rest here for you in a second. The 5v Ref is just the throttle position sensor, this code is for the actual throttle actuator, the motor that moves the throttle plates.
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Sunday, February 16th, 2025 AT 8:54 AM
Tiny
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This is the code setting criteria that has been met to set these two codes, so the desired and actual position do not meet. It sets the codes and disables the throttle body.
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Sunday, February 16th, 2025 AT 8:59 AM
Tiny
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It looks to be fully closed.
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Sunday, February 16th, 2025 AT 9:01 AM
Tiny
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Okay, so, you verified the 5v Ref already, did you check to see what the Signal wire is reading with the key on as well? To also verify the Ground wire is good, you can recheck the 5v Ref using the sensor ground and Battery negative if you haven't already done that.
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Sunday, February 16th, 2025 AT 9:07 AM
Tiny
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Actually I don't think it is fully closed. I got a better shot. I also compared it to the scrap one I bought. The scrap throttle body does look closed. But this one does not seem to be? See the updated picture.
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Sunday, February 16th, 2025 AT 9:08 AM
Tiny
AL514
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Thats with the key Off I assume, yeah that doesn't look closed, can you unplug the throttle body connector pretty easy? And with the used one, you would need to clear the codes first before it may start to function, but I'm posting the flow chart for the P1516 below anyway.
This testing is first checking the voltage levels for the two wires that control the throttle body motor, and then checking the circuit from the ECM connector to the throttle body wires to see if there is high resistance, open circuit, short to ground, etc.
It's the X2 ECM connector, so I'll find that for you, but you can do the first step to determine which step is next after that.
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Sunday, February 16th, 2025 AT 9:21 AM
Tiny
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Yes, I can remove the throttle body connector. I checked 5v ref with battery ground and it was 5v. I checked Signal with key on and it was 12v.

Do you think I should try the scrap throttle body I have? Also. Clear the codes. I do have an ODB scanner and when I try to clear the codes from it, it gives a "failure". It would not clear them no matter what I tried. So, what I did was disconnect the batter for over 10min. Would that be sufficient to clear the codes?
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Sunday, February 16th, 2025 AT 9:26 AM
Tiny
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Going back to the wire diagram you sent. I didn't catch it but there is no blue/white wire. I read it as brown/white. Actually, there is only 1 wire that has any white and that is the brown/white wire. This is the wire diagram I found.
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Sunday, February 16th, 2025 AT 9:41 AM
Tiny
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Okay, your throttle body has 6 wires on it, there are two different designs for this year, one has a TPS with 2 signal wires, the other only has 1 TPS signal wire.
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Sunday, February 16th, 2025 AT 9:44 AM
Tiny
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Okay, hang on, I missed your previous message about the 12-volts on the TPS signal wire. You can try the used TB, I'm wondering if the TPS signal wire is shorted to battery power now, can you check the TPS signal wire with it plugged in and see if you're still reading 12v, we might have to unplug the ECM X2 connector and recheck that signal wire again, I don't think there should be any 12v on it, unless that's a circuit integrity check, but sounds odd to me. This is the 6 wire TB or 5 wire?
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Sunday, February 16th, 2025 AT 9:52 AM
Tiny
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The diagram you posted matches the 6 wire TB wiring I have. But I'm having trouble finding the OEM diagram with 6 wires, there's a change in the build for this year, causing this confusion. This is the OEM I'm seeing so far.
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Sunday, February 16th, 2025 AT 9:56 AM
Tiny
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Let me recheck the voltage on the signal. I do have 6 wires.
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Sunday, February 16th, 2025 AT 9:58 AM
Tiny
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Okay, I found the correct ECM X2 connector pinout for you at least, it shows 2 TPS signal wires.
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Sunday, February 16th, 2025 AT 10:01 AM
Tiny
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Okay, actually. What would be the "signal" wire?
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Sunday, February 16th, 2025 AT 10:02 AM
Tiny
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This is the 6 wire TB pinout, TPS signal 1 (D) brown/green and signal 2 (F) brown/blue. With two signal wires one may go up and the other down when pressing the throttle, some work opposite like that, but it should still only be 0-5v.
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Sunday, February 16th, 2025 AT 10:07 AM
Tiny
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Okay, so, with the car "on", but engine "off". The voltage on the brown/green or brown/blue should go up and down. Probably opposite of each other?
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Sunday, February 16th, 2025 AT 10:12 AM
Tiny
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Sometimes they have them that way, in either case, both signal wires should vary between 0-5-volts. With a code stored though, the ECM may not move the throttle plate at all.
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Sunday, February 16th, 2025 AT 10:13 AM
Tiny
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My concern is more about the 12v reading.
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Sunday, February 16th, 2025 AT 10:14 AM

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