Civic L4-1.7L CNG (2003)
18. Check for continuity between body ground and PGM-FI main relay 1 4P connector terminals No.2 and No.4 individually.
Is there continuity?
YES - Repair short in the wire between the No.6 ECU (PCM) (15A) fuse and the PGM-FI main relay 1/injector relay. Also replace the No.6 ECU
(PCM) (15A) fuse.
NO - Go to step 19.
19. Disconnect each of the component or the connector sensors below, one at a time, and check for continuity between PGM-FI main relay 1 4P
connector terminal No.1 and body ground.
-
PGM-FI main relay 2
-
PCM connector A (31P)
-
Each injector 2P connector
-
Idle air control (IAC) valve 3P connector
-
Camshaft speed (CMP) sensor (Top dead center (TDC) sensor) 3P connector
-
Crankshaft position (CKP) sensor 3P connector
-
Injector relay 4P connector
-
Injector control module 26P connector
Is there continuity?
YES - Go to step 20.
NO - Replace the component that made continuity to body ground go away when disconnected. If the item is the PCM, update the PCM if it does
not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM,
replace the original PCM.
Also replace the No.6 ECU (PCM) (15A) fuse.
20. Disconnect the connectors of all these components.
-
PGM-FI main relay 2
-
PCM connector A (31P)
-
Injectors
-
Idle air control (IAC) valve
-
Camshaft speed (CMP) sensor (Top dead center (TDC) sensor)
-
Crankshaft position (CKP) sensor
-
Injector relay
-
Injector control module