C.E. Nierhoff & Co C520 User manual

R
C520 Alternator
Troubleshooting Guide
C.E. Niehoff & Co.
Page 1TG48B
CONTENTS
Section 1:Wiring .................................................................2
Section 2: CAN/J1939 Diagnostics ...................................3
Section 3: Basic Troubleshooting.....................................4
Section 4: Advanced Troubleshooting ..........................5-6
Battery Charging Conditions
The following conditions may be observed during cold-
start voltage tests until temperatures of electrical system
components stabilize. The time it takes to reach optimum
voltage and amps will vary with engine speed, load, and
ambient temperature.
Maintenance/Low Maintenance Lead-Acid Battery:
Traditional lead acid batteries require lowest charge volt-
age of all vehicle battery chemistries. Battery cells must
be maintained by periodically topping o󰀨 with distilled
water as required.
Maintenance-free Lead-Acid Battery:
Maintenance-free batteries are similar to Maintenance/
Low Maintenance batteries, but may require slightly higher
charge voltage.
Deep-cycle/Marine Maintenance-free Battery:
Charge acceptance of these batteries may display charac-
teristics similar to maintenance-free batteries and may
charge faster due to generally lower capacity relative to
size.
AGM (Absorbed Glass Mat) Maintenance-free Battery:
These dry-cell batteries respond better than standard
maintenance-free batteries. If battery state of charge
(SOC) drops to 75% or less, batteries should be
recharged to 95% or higher separately from engine charg-
ing system to avoid damaging charging system
components and to provide best overall performance.
Charge acceptance of these batteries may display charac-
teristics similar to maintenance batteries, but may require
higher charge voltage and will draw signicant current (<100
amps) when under 50% SOC.
Lithium Battery:
Lithium batteries have unique charging characteristics that
di󰀨er from lead acid. These batteries require charging
systems congured specically for lithium battery chemis-
tries. Contact CEN for more information on lithium battery
charging systems and components.
Voltage testing:
• Set meter to proper scale and type (AC or DC).
• Be sure to zero the meter scale or identify the meter
burden by touching meter leads together. Meter burden
must be subtracted from nal reading obtained.
• Be sure the meter leads touch source area only.
Prevent short circuit damage to test leads or source by
not allowing meter leads to touch other pins or exposed
wires in test area.
• Be sure to use CEN tools designed especially for trou-
bleshooting CEN alternators when available.
Resistance (ohm) testing:
• Set meter to proper scale.
• Be sure to zero the meter scale or identify the meter
burden by touching meter leads together. Meter burden
must be subtracted from nal reading obtained.
• Be sure meter leads touch source area only. Allowing
ngers or body parts to touch meter leads or source
during reading may alter reading.
• Be sure reading is taken when source is at 70ºF. Read-
ings taken at higher temperatures will increase the
reading. Conversely, readings taken at lower tempera-
tures will decrease the reading.
• Be sure to test directly at the source. Testing through
extended harnesses or cable extensions may increase
the reading.
• "OL" as referenced in this document refers to open cir-
cuit: "innite" resistance, typically in very high kilo- or
megaohm range depending on meter and settings.
Diode testing:
• Diodes allow current to ow in one direction only. Typi-
cal voltage drop in forward bias can range from 0.1-
0.85V. Meter should read OL in reverse bias. Check
meter user manual for meter-specic testing guidelines.
Voltage drop testing:
• Measure voltage between B+ on alternator or power
source and B- (ground) on alternator or source. Record
reading. Move to batteries or other power source and
measure again between B+ and B- terminals on battery
or other power source. The di󰀨erence between the two
readings represents voltage lost within circuit due to,
but not limited to, inadequate cable gauge or faulty con-
nections.
• Voltage drop measurements must be taken with all elec-
trical loads or source operating.
Dynamic/Live testing (Connecting power and ground to
component to test operation/function out of circuit):
• Connect jumper leads directly and securely to power
source contacts of component being tested.
• Make any connection to power and ground at power
supply or battery source terminals. Do not make con-
nection at component source terminals, as that may
create an arc and damage component source terminals.
Testing Guidelines
Professional service technicians rely on the following
guidelines when testing electrical components.

Page 2 TG0048A
Section 1:Wiring Diagram
CEN C520 Alternator Description and
Operation
C520 14 V 300 A 3-phase alternator is internally
rectified. All windings and current-conducting compo-
nents are non-moving, so there are no brushes or slip
rings to wear out.
After engine is running, regulator receives energize
signal. Regulator monitors alternator rotation and
provides field current only when it detects alternator
shaft rotating at or above idle speed.
After regulator detects alternator rotation, it gradually
applies field current, preventing an abrupt mechani-
cal load on accessory drive system. The soft start may
take up to 20 seconds.
A2-215 regulator used with some of these units is flat
temperature compensated. A 15.5 V regulator setpoint
is available for battery isolator applications.
A2-326 regulator used with some of these units in-
cludes measurement of battery current, voltage, and
temperature for adjustment of regulator setpoint.
Figure 3 — C520 Alternator with Regulator
Figure 1 — C520 Alternator/A2-215 Regulator Features
B+
terminal
T
IGN terminal
B– terminal
T
T
Figure 2 — A2-326 Remote-Mounted Regulator Features
T
LED
LED
T
T
IGN terminal
T
Regulator receptacle
T
J1939 receptacle
R
Section 1: Wiring Diagram
Page 2 TG48B

Page 3
TG0048A
Section 2: CAN/J1939 Diagnostics
CAN/J1939 Interface
DESCRIPTION AND OPERATION
The CEN A2-326 digital regulator is compatible with
SAE J1939 communications standard for vehicle net-
working.
CEN uses MIL-STD connector MS3112E12-10P to inter-
face between the A2-326 and the vehicle J1939 databus.
Mating connector is MS3116E12-10S or equivalent.
If J1939 connection is not used, the 10-pin connector
must be covered with connector cover MS3181-12CA or
equivalent. Message content is shown in Table 2.
Pin Identication
TABLE 1 – J1939 Connector
Circuit Identication
A
B
C
D
E
F
G
H
J
K
CANH
CANL
CAN SHIELD
Battery
Mfr use only
Mfr use only
Mfr use only
Temperature sensor
Voltage sensor
Current sensor
Figure 4 – J1939
Connector Pins
Regulator Readout Expected Reading
TABLE 2 – A2-326 Regulator/J1939 Readout Diagnostics (see Table 3)
Alternator Output Voltage 28 V System
Alternator Speed
Regulator Temperature
Alternator Output
Charging System Hours
13–15 V
1200 to 8000 RPM
Less than 257 F/125ºC
0–100%
>0 hours
Action—If Expected Reading Not Present
See Chart 1, page 6.
Check drive belt and charging system connections.
Decrease load on alternator.
Varies with load.
Check drive belt and charging system connections.
TABLE 3 – Message Data
PGN Name PGN Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8
ALT RPM 0xFED5 ALT RPM
ALT VOLT 0xFEF7 VOLT SETPOINT ALT VOLT REG IGN VOLT BATT VOLT
ALT TEMP 0xFEA7 REG TEMP BATT TEMP
PROPRIETARY #1 0xFFC8 BATT
CURRENT
SHUTDOWN
COUNT
BATT AGE HOUR METER MINUTES
(0-59)
ALT LOAD
PROPRIETARY #2 0xFFC9 Proprietary Content: For Manufacturer Test Only
R
Section 2: CAN/J1939 Diagnostics
Page 3TG48B

Page 4 TG0048A
Section 3: Basic Troubleshooting
C. Basic Troubleshooting
1. Inspect charging system components
Check connections at ground cables, positive
cables, and regulator harness. Repair or replace
any damaged component before troubleshooting.
2. Inspect connections of vehicle batteries
Connections must be clean and tight.
3. Determine battery type, voltage, and state
of charge
Batteries must be all the same type for system
operation. If batteries are discharged, recharge
or replace batteries as necessary. Electrical
system cannot be properly tested unless batter-
ies are charged 95% or higher. See page 1 for
details.
4. Connect meters to alternator
Connect red lead of DMM to alternator B+
terminal and black lead to alternator B–
terminal. Clamp inductive ammeter on B+
cable.
5. Operate vehicle
Observe charge voltage.
If charge voltage is above
33 volts, immediately shut
down system. Electrical
system damage may occur
if charging system is
allowed to operate at
excessive voltage. Go to
Table 4 at left.
If voltage is at or below regulator setpoint, let
charging system operate for several minutes to
normalize operating temperature.
6. Observe charge volts and amps
Charge voltage should increase and charge amps
should decrease. If charge voltage does not in-
crease within ten minutes, continue to next step.
7. Batteries are considered fully charged if charge
voltage is at regulator setpoint and charge amps
remain at lowest value for 10 minutes.
8. If charging system is not performing properly,
go to Chart 1, page 6.
A. Tools and Equipment for Job
• Digital Multimeter (DMM)
• Ammeter (digital, inductive)
• Jumper wires
If no tools are available, monitor LED code.
B. Identication Record
List the following for proper troubleshooting:
Alternator model number ______________________
Regulator model number ______________________
T
T
CAUTION
SYMPTOM ACTION
TABLE 4 – System Conditions
Check: loose drive belt; low bat-
tery state of charge.
Check: current load on system
is greater than alternator
can produce.
Check: defective wiring or poor
ground path.
Check: defective alternator
and/or regulator.
Check: defective regulator.
Check: alternator.
Check: presence of energize sig-
nal to IGN terminal on regula-
tor.
Check: battery voltage at alter-
nator output terminal.
Check: defective alternator
and/or regulator.
Low Voltage Output
High Voltage Output
No Voltage Output
R
Section 3: Basic Troubleshooting
Page 4 TG48B

Page 5
TG0048A
Section 4:Advanced Troubleshooting
A2-215 and A2-326 Regulators
DESCRIPTION AND OPERATION
A2-215 regulator is attached directly to the outside of
the alternator. A2-326 regulator is remotely mounted
from extended wiring harnesses.
Main diagnostic feature of A2-215 regulator is green
lens LED. The LED indicates field coil performance.
See Table 5 for diagnostic features and LED explana-
tions.
Main diagnostic feature of A2-326 regulator consists
of a tricolored (green, amber, red) LED located on the
side of the regulator. The LED works like a voltmeter,
measuring charging voltage. See Table 6 for diagnostic
features and LED explanations.
LED COLOR STATUS
TABLE 6 – A2-326 Regulator Diagnostics
Alternator and regulator operating normally.
GREEN Flashing*
If alternator is rotating: System voltage lower
than setpoint – electrical load exceeds alter-
nator rating at present rotor speed.
ACTION
No action required.
Check drive belt, increase RPM.
AMBER Flashing *
System voltage higher than setpoint. May occur during normal load switching.
Overvoltage condition. Attempt reset. System diag-
nosis required.
RED Flashing*
Steady OVCO tripped.
CLEAR LED off Check for system voltage at IGN terminal on
regulator. If OK, replace regulator. If not OK,
check vehicle wiring and ignition circuit.
Energize signal present, alternator not rotat-
ing or alternator speed too low for cut-in.
Energize circuit fault.
When loads decrease or speed increases, LED
should flash GREEN. If not, check drive belt
and charging system connections.
TROUBLESHOOTING A2-326 REGULATOR
Shut down vehicle and restart engine. If alternator
functions normally after restart, a “no output condi-
tion” was normal response of voltage regulator to
overvoltage condition. Inspect condition of electrical
system.
If you have reset alternator once, and electrical system
returns to normal charge voltage condition, there may
have been a one time, overvoltage spike that caused
OVCO circuit to trip.
If OVCO circuit repeats cutout a second time in short
succession and shuts off alternator F+ circuit, try
third restart. If OVCO circuit repeats cutout a third
time, check color of LED while engine is running.
* Flashing occurs twice per second.
LED CONDITION STATUS
TABLE 5 – A2-215 Regulator Diagnostics
Field on full.
GREEN On steady
ACTION
No action required.
Check drive belt, moderate RPM if necessary.
GREEN Flashing
CLEAR LED off Check condition of field circuit.
Speed of LED flashing determines alternator
output.
Field off.
R
Section 4: Advanced Troubleshooting
Page 5TG48B

Page 6 TG0048A
Section 4:Advanced Troubleshooting
(CONT’D)
Figure 5 – Alternator-to-Regulator Harness Plug
PIN CONNECTIONS
Pin A GND/B–
Pin B AC
Pin C GND/B–
Pin D B+
Pin E B+
Pin F F+
Chart 1 – No Alternator Output – Quick Diagnostic
With engine running: Does battery voltage exist at alternator B+ terminal and regulator E terminal?
Yes No
Repair vehicle harness circuit to E terminal on regulator
or B+ terminal on alternator.
T
T
With key off, engine off: Unplug alternator-to-regulator harness. Connect DMM on DC volt scale across
pins A and D, and then across pins C and E in harness plug. Does battery voltage exist for both pairs?
Yes No
With DMM on resistance scale, does the field resistance between pin F in harness plug and alterna-
torB– terminal measure about 1.6 (±0.2) ohms?
Yes No
Alternator is defective.
T
T
Alternator is defective.
T
T
With key off, engine off: Does battery voltage exist at alternator B+ terminal?
Yes No
Repair vehicle harness circuit to B+ terminal on alterna-
tor.
T
T
Momentarily (1 sec.) jumper pin F in harness plug to alterna-
tor B+ terminal. Touch shaft with steel tool to detect significant
magnetism. Is shaft magnetized?
Yes No
Alternator is defective.
T
Regulator is defective.
T
Set DMM to diode test.
Check negative diodes: Connect red lead to pin B in harness plug. Connect black lead to alternator B– termi-
nal. Meter should read OL (over limit). Reverse leads. Meter should read voltage drop.
Check positive diodes: Connect red lead to pin B in harness plug. Connect black lead to alternator B+ termi-
nal. Meter should read voltage drop. Reverse leads. Meter should read OL (over limit).
Yes No
Alternator is defective.
T
T
Remote-mounted regulator applications: Check condition of fuse in wiring harness
before troubleshooting.
R
Section 4: Advanced Troubleshooting (cont.)
Page 6 TG48B

Page 7
TG0048A
Notes
R
Page 7TG48B
If you have questions about your alternator or any of these test procedures, or if you need to locate a Factory Authorized Service Distributor, please contact us at:
C. E. Nieho󰀨 & Co.• 2021 Lee Street • Evanston, IL 60202 USA
TEL: [phone] USA and Canada • TEL: [phone] outside USA and Canada • FAX: [phone]
E-mail us at service@CENieho󰀨.com