C2178

TIRE AND WHEEL: TIRE PRESSURE WARNING SYSTEM: C2178/78: Battery Voltage Malfunction

DTC C2178/78 - Battery Voltage Malfunction

DESCRIPTION





INSPECTION PROCEDURE

ON-VEHICLE INSPECTION

1. CHECK BATTERY CONDITION
NOTE: If the battery is weak or if the engine is difficult to start, perform the following procedures.

(a) Check the battery for damage and deformation. If severe damage, deformation or leakage is found, replace the battery.
(b) Check the electrolyte quantity of each cell.
(1) For maintenance-free batteries:

- If the electrolyte quantity is below the lower line, replace the battery.
- If the electrolyte quantity is above the lower line, check the battery voltage when cranking the engine. If the voltage is less than 9.6 V, recharge or replace the battery.
HINT: Before checking the battery voltage, turn off all the electrical systems (headlights, blower motor, rear defogger, etc.).
(2) For non-maintenance-free batteries:

- If the electrolyte quantity is below the lower line, add distilled water to each cell. Then, recharge the battery and check the electrolyte's specific gravity.
Standard specific gravity:
1.25 to 1.29 at 20°C (68°F)

- If the electrolyte quantity is above the lower line, check the battery voltage when cranking the engine. If the voltage is less than 9.6 V, recharge or replace the battery.
HINT: Before checking the battery voltage, turn off all the electrical systems (headlights, blower motor, rear defogger, etc.).

(c) Turn the ignition switch off and turn on the headlight for 20 to 30 seconds. This will remove the surface charge from the battery.





(d) Measure the battery voltage between the negative (-) and positive (+) terminals of the battery.
Standard voltage:
12.5 to 12.9 V at 20°C (68°F)
If the voltage is below the specification, recharge the battery.





(e) Reference:
The indicator shows the battery condition.
HINT:
- Blue: OK
- White: Charging necessary
- Red: Insufficient electrolyte

2. INSPECT BATTERY TERMINAL AND FUSE
(a) Visually check the battery terminals.
(1) Check that the battery terminals are not loose or corroded.
(b) Check the H-fuses and fuses.
(1) Measure the resistance according to the value(s) in the table below.
Standard resistance:






If the result is not as specified, replace the fuses as necessary.
3. INSPECT FAN AND GENERATOR V BELT





(a) Check the belt for wear, cracks or other signs of damage.
If any of the following defects is found, replace the fan and generator V belt.
- The belt is cracked.
- The belt is worn out to the extent that the cords are exposed.
- The belt has chunks missing from the ribs.





(b) Check that the belt fits properly in the ribbed grooves.
HINT: Check with your hand to confirm that the belt has not slipped out of the grooves on the bottom of the pulley. If it has slipped out, replace the fan and generator V belt. Install a new fan and generator V belt correctly.

4. INSPECT GENERATOR WIRING
(a) Visually check the generator wiring.
(1) Check that the wiring is in good condition.
5. CHECK FOR ABNORMAL NOISES
(a) Listen for abnormal noises from the generator.
(1) Check that no abnormal noises are heard from the generator while the engine is running.
6. INSPECT CHARGE WARNING LIGHT CIRCUIT
(a) Turn the ignition switch to ON. Check that the charge warning light comes on.
(b) Start the engine and check that the light goes off.
If the light does not operate as specified, troubleshoot the charge warning light circuit.





7. INSPECT CHARGING CIRCUIT WITHOUT LOAD
(a) Connect a voltmeter and ammeter to the charging circuit as follows.
(1) Disconnect the wire from terminal B of the generator, then connect it to the negative (-) lead of an ammeter.
(2) Connect the positive (+) lead of the ammeter to terminal B of the generator.
(3) Connect the positive (+) lead of a voltmeter to the positive (+) terminal of the battery.
(4) Ground the negative (-) lead of the voltmeter.
(b) Check the charging circuit.
(1) Keep the engine speed at 2000 rpm and check the reading on the ammeter and voltmeter.
Standard current:
10 A or less
Standard voltage:
13.2 to 14.8 V
If the voltmeter reading is more than the standard voltage, replace the voltage regulator.
HINT: If the battery is not fully charged, the ammeter reading will sometimes be more than the standard amperage.

8. INSPECT CHARGING CIRCUIT WITH LOAD
(a) With the engine running at 2000 rpm, turn the high beam headlights ON and turn the heater blower switch to the "HI" position.
(b) Check the reading on the ammeter.
Standard current:
30 A or more
If the ammeter reading is less than the standard amperage, repair the generator.
HINT: If the battery is fully charged, the indication will sometimes be less than the standard amperage. If this is the case, add more electrical load (operate the wipers, rear window defogger, etc.) and check the reading on the ammeter again.

If the battery and charging system are normal, perform the "ECU Power Source Circuit" inspection procedure ECU Power Source Circuit.