Honda Civic Service Manual page 316

DLC Circuit Troubleshooting
lf the ECM does not communicate with the OBD ll scan
tool, Honda PGfM Tester, or l/M test equipment, do this
troubleshooting procedure.
1. Measure voltage between DLC terminal No. 16 and
body ground.
DATA LINK CONNECTOR {DLCI
(WHT/RED)
Terminal side of lemale terminals
ls therc battery voltage?
YES-Go to step 2.
NO-Repair open in the wire between DLC terminal
N o . 1 6 a n d t h e N o . 9 B A C K U P ( 7 . 5 A ) f u s e i n t h e
under-hood f use/relay box. I
Measure voltage between DLC terminals No. 4 and
N o . 1 6 .
DATA LINK CONNECTOR (DLCI
Terminal side of Jemale terminals
Is there battery voltage?
YES Go to step 3.
NO Repair open in the wire between DLC terminal
N o . 4 a n d b o d y g r o u n d . l
4 .
5 .
3. Measure voltage between DLC terminals No. 5 and
N o . 1 6 .
DATA LINK CONNECTOR {DLC)
Terminal side of female terminals
ls there battery voltage?
YES Go to step 4.
NO- Repair open in the wire between DLC terminal
N o . 5 a n d t h e E C M ( E 3 ) . t
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 ) .
M e a s u r e v o l t a g e b e t w e e n D L C t e r m i n a l s N o . 5 a n d
N o . 7 .
DATA LINK CONNECTOR {DLCI
T e r m i n a l s i d e o f l e m a l e t e r m i n a l s
ls there 8.5 V or more?
YES Go to step 10.
NO Go to step 6.
6. Turn the ignition switch OFF.
(cont'd)
1 1 - 1 0 9