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Fuel pump control module not communicating?

Tiny
DPS1028
  • MEMBER
  • 2016 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • 80,000 MILES
Checked power to the module at fuse box and got 12 volts. Main power at module, Red wire with purple at module connector only has 1.4 volts. I cannot find a broken connection. Any ideas?
Monday, August 14th, 2023 AT 7:35 PM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
The first thing I would do is check the ground at the driver's door on the body frame mount. Also, here are the wiring diagrams for the fuel pump driver module so you can see how the system works. Check out the images (below). Please let us know what happens.
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Tuesday, August 15th, 2023 AT 10:53 AM
Tiny
DPS1028
  • MEMBER
  • 4 POSTS
Thanks for the wiring diagram, Ken! After testing wiring at module and at fuse box I found a drop in voltage on the red/violet wire between the FPPM fuse and halfway point to the rear FPCM. The voltage drops to 2 volts. Ran a jumper around the problem area and truck started right up. Now I need to find the damaged spot and repair. Ground wires checked out fine.
Thanks again for the information.
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Monday, August 21st, 2023 AT 11:42 AM
Tiny
DPS1028
  • MEMBER
  • 4 POSTS
The break was in the square tube where the loom makes its turn under truck frame right under fuse panel on drivers side.
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Monday, August 21st, 2023 AT 6:58 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
That's what I am talking about, great find! Use 2CarPros anytime, we are here to help. Please tell a friend.
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Tuesday, August 22nd, 2023 AT 11:17 AM
Tiny
DPS1028
  • MEMBER
  • 4 POSTS
Thank again for the schematic. I couldn’t find it anywhere else online!
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Tuesday, August 22nd, 2023 AT 3:01 PM

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