Starter Test Results; Alternator Test Results; Diode Test Results - Midtronics JDT-1 WM User Manual

JDT-1

Starter Test Results

Decision
The starter voltage is normal and the battery is fully charged.
Cranking
Normal
The starter voltage is low and the battery is fully charged.
Low Voltage
The starter voltage is low and the battery is discharged. Fully
charge the battery and repeat the starter system test.
Charge Battery
(If the battery test result was (REPLACE or BAD CELL.) The
battery must be replaced before testing the starter.
Replace Battery
The starter voltage is high but the cranking amps are low.
Low Current
The engine didn't start and the test was aborted or the
vehicle's starting profile was not detected and the Starter
Test was skipped.
No Start

Alternator Test Results

Decision
The output from the alternator is normal.
CHARGING
NORMAL
No output detected. Check belts to ensure alternator is
rotating when engine is running.
√ Check all alternator connections including to the
NO OUTPUT
battery. Clean or replace if necessary and retest.
√ If the belts and connections are in good working
condition, replace alternator or external voltage
regulator.
Alternator not providing enough current to power electrical
loads and charge the battery.
√ Check belts to ensure the alternator is rotating with the
LOW OUTPUT
engine running.
√ Check alternator connections to and from the battery.
If loose or heavily corroded, clean or replace the cable
and retest.
Alternator voltage to the battery exceeds normal limits of a
functioning regulator.
√ Check for loose and normal ground connections. If no
HIGH OUTPUT
connection problems are found, replace the regulator.
The normal high limit of a typical automotive regulator is 14.5
volts +/–0.5. Refer to the manufacturer specifications for the
correct limit, which may vary by vehicle type.
www.midtronics.com
Action
Action

Diode Test Results

Decision
One or more diodes in the alternator are not functioning or
there is stator damage, which is shown by an excessive
amount of AC ripple current supplied to the battery.
EXCESSIVE
√ Make sure the alternator mounting is sturdy and that
RIPPLE
the belts are in good shape and functioning properly.
If the mounting and belts are good, replace the
alternator.
OPEN PHASE
Replace the alternator.
OPEN DIODE
SHORTED
DIODE
19
Midtronics Inc.
Appendix B:Test Results Decision Tables
Action
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