Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC 39, TCC Stuck Off (4L80-E): Notes
1995 Chevrolet Sportvan G20, 6.5 PSECTION Notes
PCM commands TCC PWM solenoid on by modulating TCC signal fluid acting on the converter clutch shift valve. Then TCC apply fluid applies the torque converter clutch.
DTC 39 will set when:
- DTCs 28, 71 or 74 are not set.
- TCC is commanded on.
- TCC slip speed greater than 65 RPM.
- Trans. range in D3 or D4.
- 2nd or 3rd gear.
- All conditions are met for 2 seconds.
PCM will default to no 4th gear in hot mode.
NOTE:
Test numbers refer to numbers on diagnostic chart.
- This checks mechanical and hydraulic operation of TCC, while commanded on by PCM.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.