This document warns technicians that bench testing alternators with P and D terminals without a test adapter will damage the voltage regulator. It provides a list of vehicle applications with these alternators, and describes how to identify an alternator with P and D terminals versus L and S terminals using an ohmmeter. It explains that these alternators use a half regulator circuit controlled by the vehicle's PCM through the D terminal, so applying battery voltage directly to this terminal will instantly damage the regulator.

1. PI0064/1 of 1/v2.0
***WARNING***
To bench test this unit (or like core), tester MUST use a
test adapter, PPR PN SS609. Bench testing the Alternator
without use of this module will damage the voltage
regulator portion of this unit. Contact PPR for pricing on
SS609 test adapter.
This warning affects Hitachi & Mitsubishi alternators with P and D
terminals. Applications include but may not be limited to:
• 97-98 Mazda Protégé 1.5, 1.6.
• 99 Mazda Protégé 1.8
• 96-97 Mazda MX5 Miata
• 99 Mazda MX5 Miata
• 98-99 Amigo and Rodeo 3.2
• 99 Honda Passport 3.2
A simple test to determine whether the alternator has P&D terminals
or L&S terminals is as follows:
1) Obtain a digital or analog ohmmeter.
2) Apply the meter red lead to the unknown terminal (either D
or S) and the black lead to the case.
3) The P&D type regulator will cause a low (under 1,000 ohms)
reading on the ohmmeter.
These alternators use a ½ regulator circuit instead of a conventional
voltage regulator. The vehicle’s PCM contains the field control and
uses the “D” (“Driver”) terminal on the alternator to control the field
circuit. Directly applying battery voltage to this terminal will instantly
and permanently damage the ½ regulator. The “P” (“Phase”) terminal
is electrically connected to the stator. The PCM uses this terminal
for field load indication output. This damage to the ½ regulator is
avoided when bench testing by using the test adapter PPR PN
SS309 to simulate the vehicle’s PCM.