Alternator Fr Signal Circuit Troubleshooting - Honda 2004 Odyssey Service Manual

Idle Control System

Alternator FR Signal Circuit Troubleshooting

'99-00, '02-04 Models
NOTE: Information marked with an asterisk ( ) applies
to '02-04 models.
1. Disconnect the alternator 4P connector.
2. Turn the ignition switch ON (II).
3. Measure voltage between PCM connector
terminals B20 and C5.
PCM CONNECTORS
B (25P)
LG1 (BRN/BLK)
LG1 (BRN/YEL)*
Wire side of female terminals
Is 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.
6. Start the engine. Hold the engine at 3,000 rpm with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
7. Measure voltage between PCM connector
terminals B20 and C5.
Does the voltage decrease when the headlights
and rear window def ogger are turned on?
YES The alternator FR signal is OK.
NO Go to step 8.
8. Turn the ignition switch OFF.
11-192
C (31P)
ALTF (WHT/RED)
9. Disconnect PCM connector C (31P).
10. Disconnect the alternator 4P connector.
11. Connect alternator 4P connector terminal No. 4 to
body ground with a jumper wire.
ALTERNATOR 4P CONNECTOR
Wire side of female terminals
12. Check for continuity between body ground and
PCM connector terminal C5.
PCM CONNECTOR C (31P)
Wire side of female terminals
Is there continuity?
YES Test the alternator
(see step 1 on page 4-24).
NO Repair open in the wire between the PCM (C5)
and the alternator.
13. Turn the ignition switch OFF.
14. Disconnect PCM connector C (31P).
ALTF (WHT/RED)
JUMPER WIRE
ALTF (WHT/RED)