Troubleshooting Flowchart- Altelnator (Alt) Fr Signal - Honda Prelude 1993 Service Manual

ldle Control System
Troubleshooting Flowchart- Altelnator (ALT) FR Signal
This signals the ECM when the alternator is charging.
' l
li
Inspoction ol ALT FR sign.l.
Connect the test harness between
the ECM and connectors.
Oisconnect "D" connector from
the main wire harness only, not
the ECM (see page 11-45).
Turn the ignirion switch ON.
Measure voltage between D9
(+) rerminal and 426 (-) ter-
mrnat,
Subltitut. a khown{ood ECM
and r..hock. lf pr.rcribed voltlgo
ir now availabl., rophce lh. ottgi-
nel ECM.
ls there approx. 4.5 V?
Turn the ignition swrtch OFF.
R e c o n n e c t
" D "
c o n n e c t o r t o t h e
m a i n w i r e h a r n e s s .
Warm up engine to normal oPer
ating temperatu€ (the radiator tan
comes onl.
Measure voltage between Dg
l+) terminal and A26 {-) ter-
minal.
Does the vohage decrease when
heedlighls and rear d€fogggr 8re
turned on ?
Turn the ignition switch OFF.
Do the ECM Reset Procedure (see
p a g e 1 1 - 4 3 ) .
ALT FR sign.l is OK.
4.5 V? -
A26 t-l
Vohfo
?
o o o o o o o o o o o
o o o o o o o o o o o
D 9 l + l
(To page 'l 1-10'l )