Subaru Legacy BN/BS (2015-2019) Service Manual: Inspection

Subaru Legacy BN/BS (2015-2019) Service Manual / Starting charging systems(h6do) / Battery / Inspection

WARNING:

• As batteries produce flammable gases, be careful not to bring an open flame close to the batteries.

• Ventilate sufficiently when using or charging battery in enclosed space.

• Electrolyte is corrosive acid, and has toxicity; be careful of handling the fluid.

• For safety, in case an explosion does occur, wear eye protection or shield your eyes when working near any battery. In addition, never lean over the battery.

• Be careful that the electrode does not come into contact with skin, eyes or clothing. Especially at contact with eyes, flush with water for 15 minutes and get prompt medical attention.

• Be careful not to let the electrode contact with the coated parts.

• Before starting work, remove rings, metal watch-bands, and other metal jewelry.

• Be careful not to let the metal tools contact the positive battery terminal and anything connected to it. When the operation using a metal tool to the positive terminal or anything connected to it is required, disconnect the battery ground terminal before starting the operation.

1. APPEARANCE

Check the battery case, top cover and terminal posts for dirt or cracks, and perform the following work as necessary.

• Clean the battery with water and wipe with a dry cloth.

• Apply a thin coat of grease on the terminal posts to prevent corrosion.

Check

• Normal > Go to the check item 2.

• Abnormal > Replace the battery.

2. ELECTROLYTE LEVEL

Check the electrolyte level in each cell.

CAUTION:

Do not fill beyond MAX level.

NOTE:

If the level is below the middle point between MIN level and MAX level, pour distilled water into the battery cell to bring the level to MAX.

Check

• MAX level > Go to the check item 3.

• Below the middle point between MIN level and MAX level > Fill > Go to the check item 3.

3. SPECIFIC GRAVITY OF ELECTROLYTE

Check the specific gravity of the electrolyte using a hydrometer and a thermometer.

NOTE:

• Specific gravity varies with temperature of electrolyte so that it must be corrected at 20°C (68°F) using the following calculation:

S20 = St + 0.0007 - (t − 20)

S20: Specific gravity corrected at electrolyte temperature of 20°C

St: Measured specific gravity

t: Measured temperature (°C)

• When measuring in a simplified manner using the battery terminal voltage, calculate the specific gravity by the following formula.

Specific gravity = [ 0.187 - battery terminal voltage (V) ] − 1.1

Perform the steps 1) and 2) before measuring the voltage in order to stabilize the voltage.

1) Turn the ignition switch to OFF and illuminate the headlight for 30 seconds.

2) After turning off the headlight, leave the vehicle for one minute.

• Measuring the specific gravity of the electrolyte in the battery will disclose the state of charge of the battery. The relation between specific gravity and state of charge is as shown in the figure.

(A)	Specific gravity [20°C (68°F)]	(B)	Amount of discharge (%)	(C)	Good
(D)	Need to charge or replace

(A)	Specific gravity [20°C (68°F)]	(B)	Electrolyte temperature	(C)	Good
(D)	Caution	(E)	Need charging

Check

• Specific gravity: 1.250 — 1.290, and difference between cells is 0.04 or less > Battery is normal

• Specific gravity: Less than 1.250, or difference between cells is 0.04 or more > Battery needs to be charged or replaced

4. STANDBY CURRENT

1. Prepare the circuit tester which can measure down to 1 mA.

NOTE:

For model with keyless access function, the standby current changes regularly. Therefore, prepare the analog type circuit tester.

2. Using the circuit tester, check the standby current.

(1) Check the battery. Battery > INSPECTION Battery > INSPECTION Battery > INSPECTION

NOTE:

The standby current may be displayed lower than the actual value if the battery is weak, so be sure to check the battery. Charge or replace if necessary.

(2) Check that the fuse is not blown out and is properly inserted.

(3) When non-genuine electrical parts (including parts sold in authorized workshops) are installed, remove all parts except for genuine electrical parts.

(4) Check that back-up fuse is inserted. PRE-DELIVERY INSPECTION (PDI) PROCEDURE

(5) Start the engine, and set the switch positions for each system as shown in the following table.

NOTE:

Some of the listed systems are not equipped depending on the vehicle. Set only the systems equipped on the vehicle to the positions as shown.

System	Position
Headlight	ON or Auto
Fog light	ON
Wiper (front and rear)	ON or Low speed
Audio and navigation system	ON
Rear defogger	ON
Room light	DOOR
Luggage light	DOOR
Map light	OFF
Auto A/C	ON (AUTO)
Manual A/C	ON (Speed 1)
Electronic parking brake	ON
Electrical parts other than listed above (electrical parts that users can confirm the operation with the key removed)	OFF

(6) Turn the ignition switch to OFF.

(7) Operate the front hood lock release lever to unlock the front hood.

(8) Close all the doors (including rear gate and trunk lid) and then lock the doors. (Security alarm is in set condition)

NOTE:

For model with keyless access function, take the access key 1.5 m or more away from the vehicle after the door lock. And do not put the access key close to the vehicle while measuring the standby current.

(9) Wait for 5 minutes after door lock until the standby current stabilizes.

(10) Loosen the nut which holds the ground terminal to the battery.

NOTE:

Do not remove the ground terminal.

(11) Connect the circuit tester positive terminal to the ground terminal.

NOTE:

To prevent the damage to the circuit tester, set the circuit tester range to a large value first, then gradually change it to smaller values.

(12) Connect the circuit tester negative terminal to the ground terminal installation part of the battery.

(13) While connecting the circuit tester positive terminal with the ground terminal as shown in the figure below, remove the ground terminal from the battery.

(14) Check the standby current.

NOTE:

• For model with keyless access function, the standby current changes periodically because the keyless access system continuously searches the access key (polling).

• When measuring the standby current, the reading of the circuit tester oscillates. Therefore, read the average value (median value).

• The standby current may become large when the vehicle system is activated 5 times at 30-minute intervals or 5 hours after turning the ignition switch to OFF. Therefore, the measurement should be completed in 20 minutes. If it takes more than 20 minutes, start the engine once, stop the engine, then perform the inspection.

(A)	Current/mA	(B)	Time/min	(C)	Ignition OFF
(D)	Less than 70 mA	(E)	5 seconds (system operation)	(F)	300 mA or more

Check

• When the maximum measurement value is less than 70 mA > Standby current is normal.

• When the maximum measurement value is 70 mA or more > Go to step (15).

(15) Remove all fuses one by one to identify which system changes the standby current value significantly. Fuse And Relay

(16) Check the harness and connector of the system whose standby current has changed significantly.

Charge

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