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.
Line Pressure Control during Low Loading
In D or S under low engine load condition after warming up the engine and in all ranges (P, R, N, D, or S) under the low ATF temperature condition, the PCM operates line pressure solenoid valve A, and switches the line pressure to a pressure that is lower than normal. This operation can reduce the friction in the transmission.
The PCM turns line pressure solenoid valve A on, and applies the hydraulic pressure to the PLA' cavity on the main regulator valve. When hydraulic pressure is applied to the PLA' cavity, the main regulator valve is pushed to the spring side. This operation reduces the drain port of the main regulator valve, and causes the line pressure to be lower than normal.
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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.