Alternator Fr Signal Circuit Troubleshooting - Honda Civic 2002-2003 Service Manual

Idle Control System
Alternator FR Signal Circuit Troubleshooting
1. Disconnect the alternator 4P connector from the
alternator.
2. Turn the ignition switch ON (III.
3. Measure voltage between ECM connector
terminals A24 and B13.
ECM CONNECTORS
A 131PI
1 2 I 3 I 4 5
6 7
J/l9
10
11112VV
15 16 VI18119 20 21
22 231241
~
2712812930V
I
LG1 IBRN/YELI
':L
ALTF
B 124PI
IWHT/RE
I 213 4 5
[6'7
8 9 1OIVIVI13
IV
15
V
17 18
1/1
IVI21
V
23
V
Wire Side of female terminals
/s there about 5 V?
YES-Go to step 4.
NO-Go to step 13.
4. Turn the ignition switch OFF.
5. Reconnect the alternator 4P connector.
01
6. Start 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. Measure voltage between ECM connector
terminals A24 and B13.
Does the voltage decrease when the headlights
and rear window defogger are turned on?
YES- The alternator FR signal is OK .•
NO-Go to step 8.
8. Turn the ignition switch OFF.
9. Disconnect ECM connector B (24PI.
10. Disconnect the alternator 4P connector.
11-134
11. Connect alternator 4P connector terminal No. 4to
body ground with a jumper wire.
ALTERNATOR 4P CONNECTOR
,.----,
1 2
ALTFI WHT/REOI
3 4
JUMPER WIRE
--
=
Wire side of female terminals
12. Check for continuity between body ground and
ECM connector terminal B13.
ECM CONNECTOR B 124PI
, - - - - - - - - , A L T F
IWHT/REOI
Q
=
Wire side of female terminals
Is there continuity?
YES- Test the alternator (see page 4-221 .•
NO-Repair open in the wire between the ECM
(B131 and the alternator .•
13. Turn the ignition switch OFF.
14. Disconnect ECM connector B (24PI.
•
•