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.
Linear Pressure Solenoid SLC1, SLC2, SLC3 And SLB1
The linear pressure solenoids, SLC1, SLC2, SLC3 and SLB1 are located in the transmission control system, which is fitted on the front edge of the gearbox. The designation of the solenoid is linked to the component (clutch/brake band) that the solenoid controls. The linear pressure solenoids consist of an electrical coil which controls a hydraulic valve. The solenoids are controlled with a pulsed (PWM) voltage and are grounded via the transmission control module (TCM). The hydraulic function of the solenoids is linear. The hydraulic valves are controlled by the varying current resulting from the current pulse ratio. With a high pulse ratio, i.e. high current strength (approx. 1 A), the system pressure is low, and with a low pulse ratio, i.e. low current strength, the system pressure is high. In the event of an open circuit the system pressure is at a maximum which results in hard gearshifts. Here the hydraulic valve is fully open.
The solenoids can be diagnosed.
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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.
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