Lexus RX300 (MCU15). Service manual - part 179

CH0G5–01

B04633

Voltmeter

Z11580

Charging
Necessary

Insufficient
Water

Blue

White

Red

OK

Z00015

CH–2

–

CHARGING

CHARGING SYSTEM

LEXUS RX300   (RM785E)

ON–VEHICLE INSPECTION

1.

CHECK BATTERY ELECTROLYTE LEVEL

Check the electrolyte quantity of each cell.
If under the lower level, replace the battery (or add distilled wa-
ter if possible). Check the charging system.

2.

CHECK BATTERY VOLTAGE

(a)

After having driven the vehicle and in the case that 20
minutes have not passed after having stopped the en-
gine, turn the ignition switch ON and turn on the electrical
system (headlight, blower motor, rear defogger etc.) for
60 seconds to remove the surface charge.

(b)

Turn the ignition switch OFF and turn off the electrical sys-
tems.

(c)

Measure the battery voltage between the negative (–)
and positive (+) terminals of the battery.
Standard voltage:
12.5 – 12.9 V at 20

°C (68°F)

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

HINT:
Check the indicator as shown in the illustration.
3.

CHECK BATTERY TERMINALS, FUSIBLE LINK AND
FUSES

(a)

Check that the battery terminals are not loose or cor-
roded.

If the terminals are corroded, clean the terminals.
(b)

Check the fusible link, H–fuses, M–fuse and fuses for
continuity.

4.

INSPECT DRIVE BELTS

(a)

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

If any defect has been found, 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.

N17028

Crank Pulley

Ideller Pulley

Water Pump

Compressor

:Measure point for belt looseness  and
tension

CH0086

CORRECT

WRONG

I02495

–

CHARGING

CHARGING SYSTEM

CH–3

LEXUS RX300   (RM785E)

(b)

Check the drive belt deflection by peressing on the belt at
the points indicated in the illustration with 98 N (10 kgf, 22
lbf) of pressure.
New belt 8.0 – 9.0 mm (0.35 – 0.47 in.)
Used belt 12.0 – 14.0 mm (0.43 – 0.59 in.)

HINT:

S

”New belt” refers to a belt which has been used less than
5 minutes on a running engine.

S

”Used belt” refers to a belt which has been used on a run-
ning engine for 5 minutes or more.

S

After installing a belt, check that it fits properly in the
ribbed grooves.

S

Check with your hand to confirm that the belt has not
slipped out of the groove on the bottom of the pulley.

S

After installing a new belt, run the engine for about 5 min-
utes and recheck the belt tension.

(c)

Reference:
Using a belt tension gauge, measure the belt tension.
Belt tension gauge:
DENSO BTG–20 (95506–00020)
Drive belt tension:

New belt

756 – 801 N (77 – 82 kgf)

Used belt

422 – 601 N (43 – 61 kgf)

If the belt tension is not as specified, adjust it.

5.

VISUALLY CHECK ALTERNATOR WIRING AND LIS-
TEN FOR ABNORMAL NOISES

(a)

Check that the wiring is in good condition.

(b)

Check that there is no abnormal noise from the alternator
while the engine is running.

Z03473

Battery

Ammeter

Voltmeter

Disconnect Wire
from Terminal B

Alternator

CH–4

–

CHARGING

CHARGING SYSTEM

LEXUS RX300   (RM785E)

6.

CHECK DISCHARGE WARNING LIGHT CIRCUIT

(a)

Warm up the engine and then turn it off.

(b)

Switch off all accessories.

(c)

Turn the ignition switch ”ON”. Check that the discharge
warning light is lit.

(d)

Start the engine. Check that the light goes off.

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

7.

INSPECT CHARGING CIRCUIT WITHOUT LOAD

HINT:
If a battery/alternator tester is available, connect the tester to
the charging circuit as per manufacturer’s instructions.
(a)

If a tester is not available, connect a voltmeter and amme-
ter to the charging circuit as follows:

S

Disconnect the wire from terminal B of the alterna-
tor, and connect it to the negative (–) tester probe
of the ammeter.

S

Connect the positive (+) tester probe of the amme-
ter to terminal B of the alternator.

S

Connect the positive (+) tester probe of the voltme-
ter to terminal B of the alternator.

S

Ground the negative (–) tester probe of the voltme-
ter.

(b)

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:
13.2 – 14.0 V

If the voltmeter reading is more than standard voltage, replace
the coil assembly.
8.

INSPECT CHARGING CIRCUIT WITH LOAD

(a)

With the engine running at 2,000 rpm, turn on the high
beam headlights and place the heater blower switch at
”HI”.

(b)

Check the reading on the ammeter.
Standard amperage:
30 A or more

If the ammeter reading is less than the standard amperage, re-
pair the alternator.
HINT:
If the battery is fully charged, the indication will sometimes be
less than standard amperage.

CH07D–02

B12256

Pivot Bolt

Plate Washer

Adjusting Lock Bolt

Adjusting Bolt

Alternator

Alternator Wire

Alternator Connector

Drive Belt

B12257

Pulley

Drive End Frame

z Front Bearing

Retainer

Rotor

Bearing Cover

z Rear Bearing

Bearing Cover

Alternator Washer

Coil Assembly

Front Seal Plate

Terminal Insulator

Brush Holder

Rear Seal Plate

Rear End Cover

z Non–reusable part

–

CHARGING

ALTERNATOR

CH–5

LEXUS RX300   (RM785E)

ALTERNATOR

COMPONENTS