LEAD-ACID BATTERY INSPECTION

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Warning

<<High voltage>>

•  Always observe the following thoroughly to ensure safety when inspecting or removing/installing parts in the motor compartment. Otherwise, the high voltage circuit may operate on the vehicle regardless of whether or not the main power is switched OFF or ON (READY off or on). If this occurs, it could cause electrical shock and result in serious injury or, in the worst case, death.

―  Do not select high voltage battery cooling on center display after EV system stops

―  Do not open/close doors frequently with main power switched OFF

―  Do not perform normal charging or quick charging

―  Switch to connected vehicle maintenance mode (MyMazda App connected vehicle)

―  Cancel climate control timer

―  Operate center display and turn off battery heater operation

Warning

•  The EV system is hot immediately after driving and charging, and can cause severe burns. Turn off the EV system and wait until it is cool before performing the servicing.

•  If the cooling system cap is removed while the EV system is hot, hot coolant may be ejected, causing severe burns or injury. Perform the removal of the cooling system cap when the EV system is cool.

•  When removing the cooling system cap, cover the cooling system cap with a clean cloth and remove it slowly.

•  The cooling fan may suddenly start operating regardless of the main power switch position. Keep hands and tools away from the cooling fan even if the cooling fan is not operating to prevent injury, or damage to the cooling fan. When servicing the cooling fan or parts near the cooling fan, ensure the following.

―  Do not perform normal charging or quick charging

―  Do not select high voltage battery cooling on center display after EV system stops

―  Do not open/close doors frequently with main power switched OFF

―  Access connected vehicle maintenance mode (MyMazda App connected vehicle)

―  Cancel climate control timer

―  Operate center display and turn off battery heater operation

Electrolyte Gravity

1.  Inspect the lead-acid battery as follows.

Purpose	Step	Inspection	Results	Action
Lead-acid battery examination (verification of dendrite short)	1	Using a hydrometer, measure the electrolyte gravity of all the cells and identify the one with the lowest electrolyte gravity value.	1.25 or more	The lead-acid battery is normal.
			1.17 — 1.25	Charge the lead-acid battery. (See LEAD-ACID BATTERY RECHARGING.)
			Less than 1.17	Determine a dendrite short and replace the lead-acid battery. (See LEAD-ACID BATTERY REMOVAL/INSTALLATION.)

Back-up current:

Caution

•  Do not apply electrical load when measuring the back-up current. Otherwise, the tester will be damaged.

1.  Verify that the main power is switched OFF.

2.  Disconnect the negative lead-acid battery terminal.

(See NEGATIVE LEAD-ACID BATTERY TERMINAL DISCONNECTION/CONNECTION.)

3.  Connect the tester between the negative lead-acid battery terminal (battery side) and the negative lead-acid battery terminal (wiring harness side).

Note

•  If the measurement is performed without leaving the vehicle for 10 min, the tester shows a high value (approx. 300 mA).

•  If the key or an electrical device is operated after connecting the tester, the vehicle needs to be left for approx. 40 min.

•  For vehicles with the immobilizer system, the back-up current periodically shifts synchronizing with the security indicator light flashing. Therefore, 65 mA (0.1 s) current flows when the security indicator light is turned on, and 40 mA (2 s) current flows when the security indicator light is turned off. In addition, if a measuring instrument that shows an average value is used, it will display approx. 55 mA.

4.  Measure the back-up current after leaving the vehicle for 40 min or more.

•  If the measured value is not within the standard, remove the fuses in the main fuse block and in the fuse block one by one while measuring the back-up current.

•  Inspect and repair the wiring harness and connector for the fuse that shows a decreased current value.