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Home >> Chevrolet >> 2018 >> Spark LT, Standard Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Automatic Transmission - JATCO CVT) >> Diagnostic Information and Procedures >> Line Pressure Check >> At Wide Open Throttle Engine Speed

At Wide Open Throttle Engine Speed

WARNING: This page is about a different variant/trim than selected.
  1. Check the engine oil level. Refill if necessary.
  2. With the engine warmed up, drive the vehicle.
    3. NOTE:

    When ambient temperature is 20°C (68°F), it takes about 10 minutes for the CVT fluid to warm up to 50 - 80°C (122 - 176°F).

  3. Check the CVT fluid level and condition. Refill if necessary. Refer to Transmission Fluid Level and Condition Check .
  4. Block the front and rear wheels and apply the parking brake fully.
  5. Start the engine and set A/C OFF.
  6. Set the scan tool.
  7. Select "Line Pressure" in data menu.
  8. Depress the brake pedal and shift the selector lever to the D position.
  9. While depressing the brake pedal, depress the accelerator pedal until wide open throttle position.
    10. NOTE:

    Never depress the accelerator pedal for 5 seconds or more during the test.

  10. Measure the line pressure when the engine speed is reached in wide open throttle engine speed. Then, release your foot from the accelerator pedal quickly.

    Wide Open Throttle Engine Speed (RPM)

    • 1400 - 2400 (for 1.0 engine)
    • 1200 - 2200 (for 1.4 engine)
  11. Shift the selector lever to the N position.
    12. NOTE:

    Run the engine with the idle speed for at least 1 minute.

  12. Cool the CVT fluid.
    13. NOTE:

    Keep brake pedal pressed all the way down during measurement.

  13. Shift the selector lever to the R position and perform Step 9 to Step 12.
Line Pressure Test Result

Selector Lever Position Engine Speed Line Pressure
R and D Range At Wide Open Throttle Engine Speed 1930 - 5780 kPa (279.9 - 838.3 psi): 1.0 Engine
1530 - 5580 kPa (221.9 - 809.3 psi): 1.4 Engine
Line Pressure Test Diagnosis

Result Possible Cause
Idle Speed Low for all positions (P, R, N, D) Possible causes include malfunctions in the pressure supply system and low oil pump output:
  • Oil pump wear
  • Damage of chain and sprocket
  • Pressure regulator valve or plug stuck or spring fatigue
  • Pressure regulator valve passage oil leak
  • Engine idle speed too low
Only low for a specific position Possible causes include an oil pressure leak in a passage or device related to the position after the pressure is distributed by the manual valve.
High Possible causes include a sensor malfunction or malfunction in the line pressure adjustment function:
  • Accelerator pedal position signal malfunction
  • CVT fluid temperature sensor malfunction
  • Line pressure solenoid malfunction (stuck in OFF state, open circuit, short circuit)
  • Pressure regulator valve stuck
Wide Open Throttle Engine Speed Line pressure does not rise higher than the line pressure for idle Possible causes include a sensor malfunction or malfunction in the pressure adjustment function:
  • TCM malfunction
  • Line pressure solenoid malfunction (short circuit, stuck in ON state)
  • Pressure regulator valve stuck
The pressure rises, but does not enter the standard position Possible causes include malfunctions in the pressure supply system and malfunction in the pressure adjustment function:
  • Oil pump wear
  • Line pressure solenoid malfunction (stuck)
  • Pressure regulator valve stuck
Only low for a specific position Possible causes include an oil pressure leak in a passage or device related to the position after the pressure is distributed by the manual valve.
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