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Title: Alternator Troubleshooting and Diagnostics

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Applies To: All

Change Log

Please refer to the change log text box below for recent changes to this article:

4/22/2024 - Updated article to include references to the new Autometer tool.
3/08/2022 - Updated article owner groups.

1/29/2018 - Updated the Midtronics manual hyperlink

1/27/2017 - Author updated for feedback purposes.

6/15/2017 - Corrected cable drop specs.

DESCRIPTION

This document details the procedure that must be followed to ensure proper Alternator troubleshooting and diagnostics.

The procedure requires using the AutoMeter BCT-468NAVK Tester and Alternator Diagnostic Worksheet.

NOTE: AutoMeter Warranty Authorization Codes and Charging System Charge Codes are now required on every Navistar
Warranty Alternator replacement (excluding 55 over-the-counter parts).

NOTE: While it is not required, completing the Alternator Diagnostic Worksheet is still recommended. Critical diagnostic
testing values can be recorded on this worksheet, and it is recommended to use this worksheet anytime an alternator is
diagnosed.

SYMPTOM(s)

Diagnostic Trouble Codes & Dashboard Indicator Lights:

DTC/Light Desci

No Faults or Warning Lights

Customer Observations or Concerns:
© Overcharging
© Undercharging
e Fluctuating Battery (Voltage) Gauge
e Low battery system voltage
© Red battery warning light
© Batteries aren't Charging
© Battery gauge reading too high

© Battery gauge reading too low

SPECIAL TOOL(s) / SOFTWARE

Tool Description Tool Number |Comments Instructions
AutoMeter Battery and Electrical System Analyzer | BCT-468NAVK pasttuction
Tool, Fluke 88V/A Automotive Meter Combo Kit ZTSE4357-Kit

Step|/ Action Decision

Feature code confirmation: Power Pack 3 Alternator

Does this vehicle have a Power Pack 3 alternator--DuraStar or WorkStar

Yes: Go to Power Pack 3 Diagnostics
linked Here

e Excessive cracking

e Missing/torn ribs

Inspect the accessory drive belt for the following :

1 with feature code 60AJN, 60AJP,60AAC, or GOAAE?
For further information on the Power Pack 3 feature click here No: Go to Step 2
Step] Action Decision
2 Yes: Go to Step 3

e Excessive edge wear
¢ Contamination
Note: belts may not be covered under warranty--verify warranty policy.

Is the accessory drive belt usable?

No: Replace Belt, and retest

Step

Action

Decision

Check the accessory drive belt auto tensioner for the following:
© Does the auto tensioner pulley spin freely?

© Does the tensioner arm move smoothly through its entire range of

Yes: Go to Step 4

motion?
3 . . . -
e Is there spring tension through the entire range of motion?
e Is the tensioner, at a mid-point, within its range of travel? No: Replace accessory drive belt auto
tensioner and retest
¢ Inspect for loose Alternator Pulley
Was "yes" the answer to ALL of the previous questions?
Step] Action Decision
Inspect alternator cables and connections for the following :
Yes: Go to Step 5
© Loose crimps
¢ Corrosion
4 . .
° Damage No: Repair/Replace any defective
Alternator Cables and Connections
© Proper routing and retest
Are all alternator cables and connections free of issues?
Step] Action Decision
If the Alternator has an ignition (IGN) terminal, there must be power Yes: (or IGN terminal not present):
present at all times. Go to Step 6
5
U: It meter to m re the vol he terminal. eee .
se a volt meter to measure the voltage at the t ' No: Find Circuit issue and repair. Then
Is the voltage reading 12.4V or greater? Retest.
Step|/ Action Decision
6 |/If the Alternator has a battery voltage-sensing feature.

© Verify that the sense wire is securely connected to the "S" (Sense)
Terminal

© Visually inspect the circuit to the batteries, to verify the circuit is not
damaged.

Yes: Go to Step 7

No: Reinstall/repair the Voltage

Sensing Wire on the appropriate

See Appendix D for an illustration describing the issue terminal and then retest

Note: If voltage sense is not equipped on the alternator go to Step 7. The
voltage sense wire should NOT be connected to the "L" (Lamp) Terminal

Note: For further terminal information see Appendix F.

Is the Voltage Sensing Wire hooked up correctly, and not damaged?

Step Action Decision
\AutoMeter Full System Test Full System Test Pass: Retest for
concern

Complete the “Full System Test" as described in the AutoMeter Operator Manual.

Full System Test:

* Isolated Battery Test Failed Battery: Record WAC - Replace any
* Battery Pack Test bad batteries and retest for concern

* Charging System Test

* Charging System Voltage Drop Test
7 * Staring System Test

* Starting System Voltage Drop Test

Failed Alternator: Record WAC - Replace
alternator and retest for concern

Note: Use battery stud adaptors on each battery tested. Failure to do so will | Faited starter: Record WAC - Replace

lyield inaccurate results. starter and retest for concern

Note: Keep all generated warranty codes during testing to be later submitted
lon Warranty Claim (|f warranty applies) Failed Voltage Drop: Repair or replace any
battery cables that have excess voltage
drop and retest for concern

What were the results of the full system test?

Warranty Information

When troubleshooting and replacing an alternator, technicians must utilize the AutoMeter BCT-468NAVK Tester, and obtain
a Warranty Authorization Code (WAC).

NOTE: A Warranty Authorization Code (WAC) is now required on all alternator replacements. The only exception is (55) Over
the Counter Parts Warranty replacement.

NOTE: While it is not required, completing the Alternator Diagnostic Worksheet is still recommended. Critical diagnostic
testing values can be recorded on this worksheet, and it is recommended to use this worksheet anytime an alternator is
diagnosed.

NOTE: The Midtronics EXP Tester may still be used for alternator diagnostics and Warranty Authorization Code (WAC)

generation.

Warranty Return Information

Due to the high rate of damaged alternators, all alternators sent back via warranty/service contract/service part must be
undamaged and testable.

Unwarrantable Damage includes :
¢ Stripped pulley/terminal threads
¢ Missing/damaged terminals
© Foreign object damage
© Missing parts that render unit untestable
© Cracked Housing
¢ Alternators returned in disassembled condition

Warranty Claim Coding:

108000 - Generating
System

Standard Repair Time(s):

Group: