Alternator Fr Signal Circuit Troubleshooting - Honda EP3 Service Manual

ldle Gontrol System
' t .
Alternator FR Signal Circuit Troubleshooting
Disconnect the alternator 4P connector from the
alternalor.
T u r n t h e i g n i t i o n s w i t c h O N { l l ) .
Measure voltage between ECM connector
t e r m i n a l s 4 2 4 a n d 8 1 3 .
ECM CONNECTORS
2.
3 .
A l 3 1 P l
1 2 1 3
4 5
6 1 1 | 1 . , '
I
10 1 1 1 1 2 , / 5 6 , / r8119l2C 21
23124 28129130
L
(BRN/ Y EL)
ALTF
(WHT
2 1 3 4 t 5 6
1
8
9ltal,/l/
15
Wire side of female terminals
ls there about 5 V?
YES Go to step 4.
N O - G o t o s t e p 1 3 .
4. Turn the ignition switch OFF.
5. Reconnect the alternator 4P connector.
6. Slan the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then let it idle.
7. lvleasure voltage between ECM connector
t e r m i n a l s A 2 4 a n d B 1 3 .
Does the voltage decrease when the headlights
and rear window defogger arc tutned on?
Y E S T h e a l t e r n a t o r F R s i g n a l i s O K . l
N O - G o t o s t e p 8 .
8. Turn the ignition switch OFF.
9. Disconnect ECM connector B (24P).
10. Disconnect the alternator 4P connector.
/REDI
11-134
'11.
Connect alternator 4P con necto r term inal No.4 to
body ground with a jumper wire.
ALTERNATOR 4P CONNECTOR
1
2
ALTF
3
4
IWHT/RED)
JUMPER WIRE
1 2 .
Wire side of female terminals
Check for continuity between body ground and
EClvl connector terminal 813.
ECM CONNECTOB B (24PI
Wire side of female terminals
ls there continuity?
YES-Testthe alternator (see page 4-22).1
NO Repair open in the wire between the ECM
( B 1 3 ) a n d t h e a l t e r n a t o r . l
Turn the ignition switch OFF.
Disconnect ECM connector B (24P).
\
1 3 .
't 4.