Codes P16E9-00, P0128-00 and P0700-00, check engine light on and blinking drive on the panel?

Tiny
ALVREGON
  • MEMBER
  • 2016 GMC SIERRA
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Is drivable only a few miles and then you can’t drive over 35 MPH. We change the thermostat and the temperature sensor also the cooling antifreeze shows 3 codes P16E9-00, P0128-00, P0700-00.
Thank you for your answers in advance.
Tuesday, May 13th, 2025 AT 12:22 PM

4 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,603 POSTS
There might be some confusion on the meaning of this code but from what I found this is the reason:

P16E9-00 - Engine Coolant Bypass Valve Performance
P0128-00 - Coolant Temperature Below Thermostat Regulating Temperature

Also, did you clear the codes after the repair, and did you use OEM parts? Here is the location of the coolant bypass valve and what it looks like.

"Located near the water pump assembly, mounted on or adjacent to the thermostat housing".

So, this code is another problem, please start a new thread for it.

P0700-00 - Transmission Control Module (TCM) Requesting MIL

Check out the images (below). Please let us know what happens.
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Wednesday, May 14th, 2025 AT 12:35 PM
Tiny
ALVREGON
  • MEMBER
  • 4 POSTS
Thank you, I really appreciate your help and your time. Asking at Autoparts, they said this vehicle doesn’t have an engine coolant bypass valve, just the thermostat. Does the same function? But it is already replaced and still has the same problem.
Have a great day.
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Thursday, May 15th, 2025 AT 7:59 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 51,603 POSTS
It is strange for sure; the tuck might be considered a 2017. I would call the dealer parts department to help confirm.
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Thursday, May 15th, 2025 AT 11:52 AM
Tiny
ALVREGON
  • MEMBER
  • 4 POSTS
Okay, thank you again KEN.
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Thursday, May 15th, 2025 AT 12:21 PM

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