Subaru Legacy BN/BS (2015-2019) Service Manual: Stall test inspection

Subaru Legacy BN/BS (2015-2019) Service Manual / Continuously variable transmission(tr580) / Stall test inspection

CAUTION:

Make sure no other person is around the vehicle during stall test measurement.

NOTE:

Stall test is extremely important in diagnosing the condition of CVT and engine. The test is necessary to measure the engine stall speeds in “R” and “D” range.

Purposes of the stall test:

• Operational check of forward clutch and reverse brake

• Operational check of the torque converter assembly

• Engine performance check

1. Place wheel chocks at the front and rear of all wheels and engage the parking brake.

2. Turn the A/C OFF.

3. Using the Subaru Select Monitor, check if the throttle valve operates when you depress the accelerator pedal. Subaru Select Monitor > OPERATION

4. Check the engine oil level. Engine Oil

5. Check the coolant level. Engine Coolant

6. Adjust the CVTF level. CVTF > ADJUSTMENT

7. Increase the CVTF temperature to 60 — 80°C (140 — 176°F) with the engine running and the select lever shifted to “N” or “P” range.

8. Shift the select lever to “D” range.

9. Depress the accelerator pedal to the full while fully depressing the foot brake pedal with your left foot.

10. When the engine speed stabilizes, quickly record the engine speed and release accelerator pedal. Shift the select lever to “N” range. Let the engine idle for one minute or more to cool it down.

11. Shift to “R” range and perform the same stall test.

NOTE:

• Do not perform a stall test for over 5 seconds at a time. (From closed throttle, fully open throttle to stall speed reading.) Failure to follow this instruction will cause the engine oil and CVTF to deteriorate and the clutch and brake to be adversely affected.

• Be sure to cool down the engine for at least one minute after each stall test with the select lever set in the “P” or “N” range and with the idle speed of 1,200 r/min or less.

• If the stall speed is higher than the specified range, attempt to finish the stall test in as short a time as possible, in order to prevent the CVT from sustaining damage.

Stall speed standard:

D range: 1,900 — 2,700 r/min

R range: 1,800 — 2,600 r/min

Stall test judgment

Range	Range	Probable cause
Lower than standard value	D, R	• Insufficient engine output • Torque converter malfunction
Higher than standard value	D	• Forward clutch slippage • Secondary pressure (line pressure) is low. • Variator chain malfunction
	R	• Reverse brake slippage • Secondary pressure (line pressure) is low. • Variator chain malfunction
	D, R	• Torque converter malfunction • Control valve body malfunction • TCM malfunction • Damaged harness and harness connector

Secondary pressure (line pressure) test inspection

CAUTION:• Directly after the vehicle has been running or the engine has been idling for a long time, the CVTF is hot. Be careful not to burn yourself.• Make sure no other person is around ...

Time lag test inspection

NOTE:When the select lever is shifted while the engine is idling, there will be a certain time elapse or lag before shock is felt. This symptom helps to check the condition of forward clutch and rever ...

Other materials:

Note
For procedure of each component in the EyeSight system, refer to the respective section.• Control module: Control Unit• Stereo camera: Stereo Camera• Combination meter: Combination Meter• Transmission control module (TCM): Transmission Control Module (TCM)• Stop lig ...