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Home >> Mazda >> 2018 >> CX-3 Touring, FWD >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transaxle System (Service Information) >> Mechanical System Test >> Line Pressure Test

Line Pressure Test

  1. Perform the mechanical system test preparation. (See MECHANICAL SYSTEM TEST PREPARATION .)
  2. Remove the front under cover No. 2. (See FRONT UNDER COVER NO. 2 REMOVAL/INSTALLATION .)
  3. Disconnect the wiring harness clips from the harness bracket.
    Fig 1: Wiring Harness Bracket And Clips
    G11637776Courtesy of MAZDA
  4. Remove the front splash shield. (LH) (See FRONT SPLASH SHIELD REMOVAL/INSTALLATION .)
  5. Remove the wiring harness bracket installation bolts from the transaxle and set it aside.
    Fig 2: Wiring Harness Bracket And Bolts
    G11637777Courtesy of MAZDA
  6. Remove the pressure detection square head plug.
    Fig 3: Removing Pressure Detection Square Head Plug
    G11637778Courtesy of MAZDA
    WARNING:
    • Do not remove the square head plug when the ATF temperature is high. Otherwise, ATF could overflow and cause severe burns or serious injury. Remove the square head plug when the transaxle and ATF temperatures are low.
    NOTE:
    • Use a suitable oil pressure gauge that corresponds to the line pressure because the maximum scale value differs depending on the oil pressure gauge.
  7. Install SSTs (49 D019 908, 49 D019 909, 49 D019 910, 49 D019 911, 49 D019 913) to the line pressure detection port as shown in the figure.
    Fig 4: Installing SSTs To Line Pressure Detection Port
    G11637779Courtesy of MAZDA
  8. Start the engine.
  9. Warm up the engine until the ATF temperature is 60-70 °C {140-158 °F}.
  10. Shift the selector lever to the D position.
  11. Measure the line pressure while idling in D position.
  12. Measure the line pressures while idling in the M (1st gear) and R positions using the same procedure.
  13. Stop the engine.
  14. Change the low-pressure gauge (49 D019 908) to the high-pressure gauge (49 D019 907).
    Fig 5: Changing Low-Pressure Gauge (49 D019 908) To High-Pressure Gauge (49 D019 907)
    G11637780Courtesy of MAZDA
  15. Start the engine.
  16. Measure the line pressure while stalling in D position.
    1. Strongly depress the brake pedal with the left foot.
    2. Shift the selector lever to the D position.
      CAUTION:
      • To prevent damage to the transaxle, measure the line pressure while stalling (Step (3)-(4)) within 5 s.
    3. Slowly depress the accelerator pedal fully with the right foot all the way down.
    4. Read the line pressure quickly while stalling, and remove the right foot from the accelerator pedal.
    5. Shift the selector lever to the N position and idle for 1 min or more.
  17. Measure the line pressure while stalling for positions other than D in the same procedure.
    • If there is any malfunction, one of the following causes may have occurred:
    Condition Possible cause
    Lower than specification Lower in R, D, and M (1GR) position
    • Oil pump wear
    • ATF leakage from oil pump, control valve body, and transaxle case
    • Pressure regulator valve sticking
    • Pressure control solenoid malfunction
    • Solenoid reducing valve sticking
    Lower in D and M (1GR) position
    • ATF leakage from low clutch hydraulic circuit
    Lower in R and M (1GR) position
    • ATF leakage from low and reverse brake hydraulic circuit
    Lower in R position
    • ATF leakage from R-3-5 brake hydraulic circuit
    Higher than specification Higher in R, D, and M (1GR) position
    • Pressure regulator valve sticking
    • Pressure control solenoid malfunction

    Line pressure 

    Measurement conditions Specification (kPa {kgf/cm2, psi})
    Idling R position 500-700 {5.10-7.13, 72.6-101.0}
    D and M (1GR) position 330-470 {3.37-4.79, 47.9-68.1}
    Stalling R position 1, 790-2, 100 {18.26-21.41, 259.7-304.5}
    D and M (1GR) position 970-1, 170 {9.90-11.93, 141.0-169.6}
  18. Stop the engine.
  19. Remove the SSTs.
    WARNING:
    • If the SST is removed when the ATF temperature is high, ATF could overflow and cause severe burns or serious injury. Remove the SST when the transaxle and ATF temperatures are low.
  20. Install a new square head plug.
    Fig 6: Installing Square Head Plug
    G11637781Courtesy of MAZDA
    NOTE:
    • Do not reuse the square head plug because a sealant coating has been applied.

    Tightening torque 

    7.2-9.8 N.m {74-99 kgf.cm, 64-86 in.lbf}

  21. Tighten the wiring harness bracket installation bolts in the order shown in the figure.
    Fig 7: Wiring Harness Bracket Bolts Tightening Sequence
    G11637782Courtesy of MAZDA

    Tightening torque 

    8-10 N.m {82-101 kgf.cm, 71-88 in.lbf}

  22. Install the front splash shield. (LH) (See FRONT SPLASH SHIELD REMOVAL/INSTALLATION .)
  23. Connect the wiring harness clips to the harness bracket.
    Fig 8: Wiring Harness Bracket And Clips
    G11637783Courtesy of MAZDA
  24. Install the front under cover No. 2. (See FRONT UNDER COVER NO. 2 REMOVAL/INSTALLATION .)