2012 Infiniti M35hFACTORY OEM SERVICE PROCEDURE

LINE PRESSURE CONTROL: System Description

  • When input torque signal corresponding to engine and motor driving force is transmitted from HPCM to TCM, TCM controls line pressure solenoid valve.

    This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the pressure of the operating oil discharged from the mechanical oil pump to the line pressure most appropriate to the driving state.

  • The TCM has stored in memory a number of patterns for the optimum line pressure characteristic for the driving state.
  • In order to obtain the most appropriate line pressure characteristic to meet the current driving state, the TCM controls the line pressure solenoid current value and thus controls the line pressure.

Normal Control

Each clutch is adjusted to the necessary pressure to match the engine and motor drive force.

It judges the vehicle drive mode based on the driving mode signal transmitted by HPCM and adjusts the line pressure to give the most appropriate value.

Fig 1: Line Pressure Characteristic Graph (Normal Condition)
G08255399Courtesy of NISSAN NORTH AMERICA, INC.

During Shift Change

The necessary and adequate line pressure for shift change is set. For this reason, line pressure pattern setting corresponds to engine torque and gearshift selection.

Fig 2: Line Pressure Characteristic Graph (During Shift Change)
G08255400Courtesy of NISSAN NORTH AMERICA, INC.

At Low Fluid Temperature

When the A/T fluid temperature drops below the prescribed temperature, in order to speed up the action of each friction element, the line pressure is set higher than the normal line pressure characteristic.

Fig 3: Line Pressure Characteristic Graph (At Low Fluid Temperature)
G07013418Courtesy of NISSAN NORTH AMERICA, INC.
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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.