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Chevrolet Silverado / GMC Sierra. Manual - part 1698
2. Verify the cold cranking amperage (CCA), and reserve capacity (RC) and/or amp hour
(AH) rating of the battery to the original battery or original equipment (OE) specification.
Refer to Battery Usage.
If the battery does not meet or exceed specifications, replace the battery.
3. Verify that the battery cables are clean and tight. The battery terminal bolts should be
torqued as specified in Fastener Tightening Specifications.
If the battery cable(s) need to be cleaned, clean as required and tighten as specified.
If the battery cable(s) are damaged, replace then tighten as specified.
4. Install the J 42000 and follow directions supplied by the tester. See Special Tools.
If the tester calls for charging the battery, refer to Battery Charging.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Battery Positive Cable Replacement (4.3L) or Battery Positive Cable Replacement
(4.8L, 5.3L, 6.0L, and 6.2L) or Battery Positive Cable Replacement (6.6L)
Battery Negative Cable Replacement (4.3L) or Battery Negative Cable Replacement
(4.8L, 5.3L, 6.0L, and 6.2L) or Battery Negative Cable Replacement (6.6L)
Battery Replacement
BATTERY CHARGING
Tools Required
J 42000 Battery Tester. See Special Tools.
For best results, use an automatic taper-rate battery charger with a voltage capability of 16
volts.
The charging area should be well ventilated.
Do not charge a battery that appears to be frozen. Allow the battery to warm to room
temperature and test it using the J 42000 before charging. See Special Tools.
Battery State of Charge
IMPORTANT: Using voltage to determine the batteries state of charge (SOC) is
only accurate after the battery has been at rest for 24 hours. This
is enough time for the acid in each cell to equalize. If the battery
has been charged or discharged in the past 24 hours, the battery
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
The maintenance-free batteries SOC is estimated by reading the voltage of the battery across the
battery terminals. Because the voltage is affected by current flow into or out of the battery, the
engine must be stopped and all electrical loads turned OFF, including parasitic loads, when
checking the voltage. The voltage can also be affected if the battery has just been charged or
discharged, so it is important to consider what has happened to the battery in the time just before
testing. Use the following procedure to determine the batteries SOC:
1. Be sure all electrical loads are turned OFF.
2. Determine whether the battery has been used in a vehicle or charged within the past 12
hours.
If the answer is no, the terminal voltage will be stabilized and no action is necessary
before reading the voltage. Skip to step 3.
If the answer is yes, terminal voltage will not be stabilized and you should wait 12
hours since the last time the battery was used.
3. Estimate the battery temperature by determining the average temperature to which the
battery has been exposed for the past 12 hours.
4. Measure the battery voltage at the battery terminals. Refer to the following table to
determine the SOC according to the estimated battery temperature:
Use the SOC information as follows:
A battery with a SOC that is below 65 percent must always be recharged before returning it
to service or continuing storage.
A battery with a SOC that is 65 percent or greater is generally considered to be charged
SOC will only be an estimate.
IMPORTANT: The table is accurate to 10 percent only after the battery has
been at rest for 12 hours.
Battery Voltage
% Charge at 0°C (32°F)
% Charge at 25°C (75°F)
12.75 V
100%
100%
12.7 V
100%
90%
12.6 V
90%
75%
12.45 V
75%
65%
12.2 V
65%
45%
12.0 V
40%
20%
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
enough in order to be returned to normal service or in order to continue storage. However,
if the battery is being used in slow traffic or with short drive times, or if the temperature is
very hot or very cold, the battery should be fully charged, to at least 90 percent, before
returning it to service or continuing storage.
Charging Time Required
The time required to charge a battery will vary depending upon the following factors:
The battery charger capacity-The higher the charger amperage, the less time it will take to
charge the battery.
The SOC of the battery-A completely discharged battery requires more than twice as much
charging time as a half charged battery. In a discharged battery with a voltage below 11
volts, the battery has a very high internal resistance and may only accept a very low current
at first. Later, as the charging current causes the acid content to increase in the electrolyte,
the charging current will increase. Extremely discharged batteries may not activate the
reversed voltage protection in some chargers. Refer to the manufacturer's instructions for
operating this circuitry.
The temperature of the battery-The colder the battery is, the more time it takes to recharge
the battery. The charging current accepted by a cold battery is very low at first. As the
battery warms, the charging current will increase.
Charging Procedure
When charging side-terminal batteries with the battery cables connected, connect the charger to
the positive cable bolt and to a ground located away from the battery. When charging side-
terminal batteries with the battery cables disconnected, install the battery side terminal adapters
and connect the charger to the adapters.
Tighten: Tighten the battery side terminal adapters to 15 N.m (11 lb ft).
Use the following procedure to charge the battery:
1. Turn OFF the charger.
NOTE:
Turn OFF the ignition when connecting or disconnecting the battery
cables, the battery charger or the jumper cables. Failure to do so
may damage the ECM/PCM or other electronic components.
NOTE:
Refer to Fastener Notice.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
2. Ensure that all of the battery terminal connections are clean and tight.
3. Connect the charger positive lead to the battery positive terminal on the battery or the
remote jumper stud underhood.
4. Connect the negative charger lead to a solid engine ground or to a ground stud in the engine
compartment that is connected directly to the battery negative terminal, but away from the
battery. If the negative battery cable is disconnected and a terminal adapter is being used,
connect directly to the adapter.
5. Turn ON the charger and set to the highest setting for normal charging.
6. Inspect the battery every half hour after starting the battery charger.
Charge the battery until the taper-rate charger indicates that the battery is fully
charged.
Estimate the battery temperature by feeling the side of the battery. If it feels hot to the
touch or its temperature is over 45°C (125°F), discontinue charging and allow the
battery to cool before resuming charging.
7. After charging, test the battery. Refer to Battery Inspection/Test.
BATTERY ELECTRICAL DRAIN/PARASITIC LOAD TEST
Tools Required
J 38758 Parasitic Draw Test Switch. See Special Tools.
Diagnostic Aids
If the vehicle is equipped with an auxiliary battery (TP2), verify that there is not a fuse
installed in the STUD 1 Fuse 70 position of the underhood fuse block. A plastic plug may
be installed in this position instead of a fuse. If a fuse is installed in this position and any
optional equipment is powered by the auxiliary battery, it will discharge the primary battery
in addition to the auxiliary battery.
Verify that all accessories are turned OFF, including optional accessories that the vehicle
may have been wired for, but does not have installed, such as auxiliary lights. If an optional
accessory swich is left in the ON position, it may energize a relay that will discharge the
battery over time, even if the accessory is not installed on the vehicle.
Be sure to rule out any possible obvious influences, such as customer error or aftermarket
NOTE:
Do not connect the negative charger lead to the housings of
other vehicle electrical accessories or equipment. The action
of the battery charger may damage such equipment.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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