CHEVROLET PLYMOUTH ACCLAIM 1993 Service Manual

GENERATOR TEST PROCEDURES ON VEHICLE INDEX
page page
Charging System Diagnostics (Fig. 1) ......... 19
Current Output Test ...................... 19 Output Wire Resistance Test
................ 19
CHARGING SYSTEM DIAGNOSTICS (Fig. 1)
OUTPUT WIRE RESISTANCE TEST
The generator output wire resistance test shows
the amount of voltage drop across the generator out-
put wire between the generator B+ terminal and the
positive battery post.
PREPARATION
Before starting test, make sure the vehicle has a
fully charged battery. Tests and procedures to check
for a fully charged battery is shown in the Battery
section. (1) Turn the ignition switch OFF.
(2) Disconnect battery NEGATIVE cable.
(3) Disconnect the generator B+ output wire from
the generator output battery terminal (Fig. 2). (4) Connect a 0-150 ampere scale (DC) ammeter in
series between B+ terminal and output wire (Fig. 2
and 3). Connect positive lead to B+ terminal, and
negative lead to output wire. (5) Using o-18 volt scale voltmeter, connect the
positive lead to the disconnected (B+) output wire
(Fig. 2). Connect the negative lead to positive battery
post. (6) Remove fresh air hose between Powertrain
Control Module and air cleaner if necessary. (7) Connect jumper wire between a good ground
and K20 circuit terminal at the back of the genera-
tor.
CAUTION: Do not connect the A142 circuit terminal
(Fig. 2) to ground the Fusible link will burn.
(8) Connect an engine tachometer and connect bat-
tery negative cable. (10) Connect a volt/amp tester equipped with a
variable carbon pile rheostat between battery termi-
nals (Fig. 4).
Caution: Be sure the carbon pile is in OFF position
before connecting leads.
TEST
(1) Start engine. Immediately after starting, re-
duce engine speed to idle. (2) Adjust engine speed and carbon pile to main-
tain 20 amperes flowing in the circuit. Observe volt-
meter reading. Voltmeter reading should not exceed
0.5 volts.
RESULTS
If a higher voltage drop is shown, inspect, clean
and tighten all connections between generator B+
terminal and battery positive post. A voltage drop
test may be performed at each connection to locate a
connection with excessive resistance. If resistance
tests are satisfactory, reduce engine speed, turn off
carbon pile, and turn off ignition switch. (1) Disconnect battery negative cable.
(2) Remove test ammeter, voltmeter, carbon pile,
and tachometer. (3) Remove jumper wire.
(4) Connect generator output wire to generator B+
terminal. (5) Connect battery negative cable.
(6) Connect fresh air hose between Powertrain
Control Module and air cleaner if removed.
CURRENT OUTPUT TEST
The current output test decides whether the gener-
ator can deliver its rated current output. For gener-
ator identification and output amperage
specifications, refer to Generator Specifications. For generator maximum voltage at individual tem-
peratures, refer to Generator Output Voltage Specifi-
cations.
PREPARATION
Before starting any tests, make sure the vehicle
has a fully charged battery. Tests and procedures to
check for a fully charged battery is shown in Battery
section. (1) Disconnect battery negative cable.
(2) Disconnect output wire at the B+ terminal
(Figs. 2 and 5). (3) Connect a 0-150 ampere scale (DC) ammeter in
series between the B+ terminal and output wire.
Connect Positive lead to B+ terminal and negative
lead to output wire. (4) Using 0-18 voltmeter, connect positive lead to
B+ terminal (Figs. 2 and 5). Connect negative lead
to a good ground.
Ä BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 19

Fig. 1 Charging Diagnostics
8A - 20 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS Ä

(5) Connect an engine tachometer and connect bat-
tery negative cable. (6) Connect a volt/amp tester equipped with a vari-
able carbon pile rheostat between battery terminals
(Fig. 6). Be sure carbon pile is in OFF position before
connecting leads. (7) Remove fresh air hose between Powertrain
Control Module computer and air cleaner if neces-
sary. (8) Full field the generator. Connect a jumper wire
between a good ground and K20 circuit terminal at
the back of the generator (Figs. 2 and 5).
CAUTION: Do not connect the A142 circuit terminal
(Fig. 2) to ground. Fusible link will burn.
TEST
(1) Start the engine. Immediately after starting,
reduce engine speed to idle.
Fig. 2 Generator Wiring Connections
Fig. 3 Generator Output Wire Resistance Test
Fig. 4 Volt/Amp Tester Connections
Ä BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 21

(2) Adjust the carbon pile and engine speed in
steps until an engine speed of 1250 rpm, and a volt-
meter reading of 15 volts is obtained.
CAUTION: Do not allow the battery voltage to ex-
ceed 16 volts. (3) The generator amperage must meet the output
requirements for the particular generator being
tested. Refer to Generator Specifications for genera-
tor identification and amperage outputs.
RESULTS
(1) If amperage reading is less than specified, and
generator output wire resistance is not found exces-
sive from the previous tests, generator should be re-
placed. Refer to Group 8B, Battery/Starter/Generator
Service, Generator Replacement. These generators
are not intended to be disassembled for service. It
must be replaced as an assembly. (2) After current output test is completed, reduce
engine speed, turn off carbon pile, and turn off igni-
tion switch. (3) Disconnect battery negative cable.
(4) Remove test ammeter, voltmeter, tachometer
and carbon pile. (5) Remove jumper wire between K20 circuit ter-
minal and ground. (6) Connect output wire to B+ terminal.
(7) Connect negative battery cable.
(8) Connect fresh air hose between powertrain con-
trol module and air cleaner if removed.
Fig. 5 Generator Current Output Test
Fig. 6 Volt/Amp Tester Connections
8A - 22 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS Ä

FAULT CODESÐON BOARD DIAGNOSTICS INDEX
page page
Diagnostic Testing Using Fault Codes ......... 24
Drb II Diagnostic Tester ................... 24 General Description/Information
.............. 23
GENERAL DESCRIPTION/INFORMATION
Another way of diagnosing charging system prob-
lems can be accomplished using the On Board Diag-
nostic System Fault Codes. A Fault Code shows a potential problem in a mon-
itored circuit, or a condition caused by a faulty component. A
Fault Code can be retrieved by turning the ignition
switch ON-OFF-ON-OFF-ON without starting the
engine, and counting the number of flashes of the
Malfunction Indicator (CHECK ENGINE) Lamp in
the instrument cluster.
EXAMPLES:
² If the Malfunction Indicator (Check Engine) Lamp
flashes four times, pauses, and flashes one more
time, a Code 41 is shown. The first set of four flashes
indicates number four. The second set of one flash in-
dicates one.
² If the Malfunction Indicator (Check Engine) Lamp
flashes four times, pauses, and flashes six more
times, a Code 46 is shown. The first set of four
flashes indicates number four. The second set of six
flashes indicates six.
² If the Malfunction Indication (Check Engine)
Lamp flashes four times, pauses, and flashes seven
more times, a Code 47 is shown. The first set of four
flashes indicates number four. The second set of
seven flashes indicates seven. POWERTRAIN CONTROL MODULE
The Powertrain Control Module is equipped with
On Board Diagnostic features and monitors all en-
gine control circuits during a run/drive period. If a
circuit or system does not perform properly, the pow-
ertrain control module will file in memory a preset
Fault Code. This can be used to help in diagnosing a
problem. After 50 to 100 ignition switch ON/RUN cy-
cles, the memory will be erased if the fault does not
reoccur. The Powertrain Control Module is located in the
engine compartment outboard of the battery (Fig. 7).
Refer to Fig. 8 Generator Fault Codes Chart for re-
lationships of generator/charging system Fault Code
numbers.
Fig. 7 Powertrain Control Module
Ä BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 23

DIAGNOSTIC TESTING USING FAULT CODES
For diagnostic testing when using the fault codes,
refer to Fig.9 through 13.
DRB II DIAGNOSTIC TESTER
TESTING FAULT CODES
A more accurate device to retrieve fault codes is
Diagnostic Tool (DRB II). This diagnostic tool,
plugged into the diagnostic connector (Fig. 7) located
near the battery, will display fault descriptions. The
DRB II also can test various circuits and component
functions. Refer to the instructions provided with the
(DRB II) tool being used. Descriptions of Fault Codes
for other vehicle systems can be found in the General
Diagnosis sections of Group 14, Fuel System.
Fig. 8 Generator Fault Codes
8A - 24 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS Ä

Fig. 9 Check For Inadequate/Low Charging
Ä BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 25

Fig. 10 Check For Overcharging
8A - 26 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS Ä

Fig. 11 Generator Wiring Connections
Fig. 12 Powertrain Control Module Connector
Fig. 13 Electrical Resistance Test
Ä BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 27

SPECIFICATIONS
STARTER/BATTERY
GENERATOR AMPERAGE/IDENTIFICATION NUMBERS
8A - 28 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS Ä