On-Vehicle Testing: Battery

check the electrolyte quantity of each cell.

If under the lower level, replace the battery (or add distilled water if possible), and check the charging system.

• Measure the battery voltage between the negative (-) and the positive (+) terminals of the battery.

  Standard voltage: 12.2 - 12.9 V at 20° C (68° F) 

  HINT:

  Fig 1: Measuring Battery Voltage

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  • Before measuring the voltage, turn the ignition switch OFF and turn off the electrical systems (headlight, blower motor, rear defogger etc.) to remove the surface charge.
  • If the vehicle has been running, wait 20 minutes or more after the vehicle stops before measuring the battery voltage.

If the voltage is less than specification, charge the battery.

1. Check that the battery terminals are not loose or corroded.
2. Check the fuses for continuity.

HINT: A belt tensioner is used, so checking the belt tension is not necessary.

Fig 2: Checking Drive Belt

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Visually check the drive belt for excessive wear, frayed cords etc.

   If necessary, replace the drive belt.

   HINT:

   • Cracks on the rib side of a drive belt are considered acceptable. If the drive belt has chunks missing from the ribs, it should be replaced.
   • The drive belt tension can be released by turning the belt tensioner counterclockwise. The pulley bolt for the belt tensioner has a left-hand thread.
2. Check the belt tensioner operation.
   • Check that the belt tensioner moves downward when the drive belt is pressed down at the points indicated in the illustration with approx. 98 N (10 kgf, 22 lb.ft) of force.
   Fig 3: Checking Belt Tensioner Operation
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • Check the alignment of the belt tensioner pulley to make sure the drive belt has not slipped off the pulley.

     If necessary, replace the belt tensioner.

   Fig 4: Checking Arrow Mark On Belt Tensioner
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • Check that the arrow mark on the belt tensioner falls within area A of the scale

     If it is outside area A, replace the drive belt

   HINT:

   • When a new belt is installed, it should lie within area B.

     If not, the drive belt is not correct.

   • After installing a belt, check that it fits properly in the ribbed grooves.
   • Check by hand to confirm that the belt has not slipped out of the groove on the bottom of the pulley.
   Fig 5: Correct And Incorrect Tensioning
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Check that the wiring is in good condition.
2. Check that there is no abnormal noise from the generator while the engine is running.

1. warm up the engine and then turn it off.
2. turn off all accessories.
3. Turn the ignition switch "ON". Check that the charge warning light is lit.
4. Start the engine. Check that the light goes off.

   If the light does not go off as specified, troubleshoot the charge light circuit.

HINT: If a battery/generator tester is available, connect the tester to the charging circuit as per manufacturer's instructions.

Fig 6: Inspect Charging Circuit Without Load

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. If a tester is not available, connect a voltmeter and ammeter to the charging circuit as follows:
   • Disconnect the wire from terminal B of the generator and connect it to the negative (-) probe of the ammeter.
   • Connect the positive (+) probe of the ammeter to terminal B of the generator.
   • Connect the positive (+) probe of the voltmeter to terminal B of the generator.
   • Ground the negative (-) probe of the voltmeter.
2. Check the charging circuit as follows:

   With the engine running from idling to 2,000 rpm, check the reading on the ammeter and voltmeter.

   Standard amperage: 10 A or less 

   Standard voltage: 

   At 25° C (77° F): 13.7 - 14.7 V 

   At 115° C (239° F): 13.2 - 14.0 V 

   If the voltmeter reading is more than standard voltage, replace the voltage regulator.

   If the voltmeter reading is less than standard voltage, check the voltage regulator and generator as follows:

   Fig 7: Locating Terminal F

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • With terminal F grounded, start the engine and check the voltmeter reading of terminal B.
   • If the voltmeter reading is more than standard voltage, replace the voltage regulator.
   • If the voltmeter reading is less than standard voltage, check the generator.

1. With the engine running at 2,000 rpm, turn on the high beam headlights and place the heater blower switch at "HI".
2. Check the reading on the ammeter.

   Standard amperage: 30 A or more 

   If the ammeter reading is less than the standard amperage, repair the alternator.

   HINT: If the battery is fully charged, the indication will sometimes be less than standard amperage.