23A-HYDRAULIC PRESSURE TEST

HYDRAULIC PRESSURE TEST

caution

This test must be performed with the transmission fluid temperature within the range of 70 to 80°C (158 to 176°F).

1. Check the engine oil level, and add if necessary.

2. Warm up the engine, and then perform test drive for approx. ten minutes.

3. Check the transmission fluid for leaks, level and contamination. Then top up or change if necessary.

4. Operate the parking brake securely, and then chock the wheels.

5. Connect the scan tool (M.U.T.-III), and then start the engine.

warning

For safety, operators must not stand in front of and at the rear of the vehicle during this test.

caution

During this test, leave the brake pedal depressed fully.

Use the scan tool (M.U.T.-III) (data list item No. 20: Secondary pressure) to measure the secondary pressure (line pressure) by observing the conditions listed in the hydraulic pressure table.

7. Stop the engine.

8. If not within the standard value, take necessary steps according to the hydraulic pressure test diagnosis table.

Hydraulic pressure table (reference value)

Selector lever position	During engine idling	During engine stall
P, N	0.50 MPa	-
R, D (B)	0.50 - 1.18 MPa	4.04 - 4.54 MPa

Hydraulic pressure test diagnosis table

Judgment result		Probable cause		Remedy
During engine idling	Low at all ranges [P, R, N, D (B)]	The hydraulic pressure delivery system or the oil pump may be defective.	Worn oil pump	Replace the transaxle assembly.
			Damaged oil pump chain and sprocket	Replace the transaxle assembly.
			Defective pressure regulator valve, or deteriorated spring	Replace the valve body assembly.
			Leaks in the hydraulic pressure circuit ranging from the oil strainer via the oil pump to the pressure regulator valve	Replace the transaxle assembly.
			The engine idling speed is low.	Check the engine system, and repair or replace if necessary.
	Low at certain range(s) only.	Oil leaks may be present in the device or circuit relating to that range.		Replace the transaxle assembly.
	High	Sensor(s) or the pressure adjusting function may be defective.	Malfunction of the accelerator pedal position sensor	Check the accelerator pedal position sensor, and repair or replace if necessary.
			Malfunction of the oil pressure sensor	Replace the valve body assembly.
			Malfunction of the line pressure solenoid valve (stuck OFF, open circuit or short circuit)
			Malfunction of the pressure regulator valve
During engine stall	Oil pressure does not rise from that during the engine idling.	Sensor(s) or the pressure adjusting function may be defective.	Malfunction of TCM	Check the TCM, and repair or replace if necessary.
			Malfunction of the line pressure solenoid valve (stuck ON or short circuit)	Replace the valve body assembly.
			Malfunction of the pressure regulator valve	Replace the valve body assembly.
	Oil pressure rises, but is not within the standard value.	The pressure supply system, sensor(s) or the pressure adjusting function may be defective.	Worn oil pump	Replace the transaxle assembly.
			Malfunction of the line pressure solenoid valve	Replace the valve body assembly.
			Malfunction of the pressure regulator valve	Replace the valve body assembly.
	Low at certain range(s) only.	Oil leaks may be present in the device or circuit relating to that range.		Replace the transaxle assembly.