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 66, 3-2 Control Solenoid CKT Fault - "G" Series 4L60-E: Notes
Hydraulically, the 3-2 control solenoid coordinates apply rate of 2-4 band with hydraulic release, of 3-4 clutch during a 3-2 downshift. PCM continually monitors 3-2 circuit duty cycle depending on commanded state of circuit. When transmission is in 1st gear, duty cycle of solenoid is equal to zero. When transmission is in 2nd gear or higher, duty cycle of solenoid will be about 90 percent. When transmission downshifts, 3-2, duty cycle of solenoid will drop. DTC 66 will set when:
- PCM commands solenoid on and voltage remains high (B+) for 4 seconds.
- PCM commands solenoid off and voltage remains low (zero volts) for 4 seconds.
PCM will default to a delayed (soft) landing to 3rd gear and 3rd gear starts.
- This test checks function of 3-2 control solenoid and internal transmission harness.
- This test checks for power to 3-2 control solenoid from ignition through fuse.
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.