p0740 code still coming up?

2006 GMC SIERRA
340,000 MILES • 5.3L • AUTOMATIC
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LORTEGA957
  • MEMBER
  • 5 POSTS
well here's my situation. I just replaced all solenoids and the harness. and a p0740 still coming up. can you guys help me out before I start putting more money
Aug 9, 2026 at 3:22 PM
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STRAILER
  • ✓Experienced Mechanic
  • 55,214 POSTS
Hello, I can help you fix it,

P0740 on a 2006 GMC Sierra is a Torque Converter Clutch (TCC) circuit malfunction

So since you did the solenoid already you might have a bad torque converter, but it is easy to command the solenoid on with a bi direction scanner. this video will show you how to use one.

CAN SCAN - https://youtu.be/u-4syLc-ifQ


at 340k it might be time for a rebuilt unit.

Aug 10, 2026 at 11:24 AM
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