Suzuki WagonR+ RB310 Service Manual page 2401

6-42 ENGINE DIAGNOSIS
TABLE A-3 ECM POWER AND GROUND CIRCUIT CHECK – MIL
DOESN'T LIGHT AT IGNITION SWITCH ON AND ENGINE DOESN'T
START THOUGH IT IS CRANKED UP
CIRCUIT DESCRIPTION
Ignition
switch
Main
fuse
When the ignition switch tuned ON, the main relay turns ON (the contact point closes) and the main power is sup-
plied to ECM.
INSPECTION
STEP
1 Main Relay Operating Sound Check
Is operating sound of main relay heard at ignition switch ON?
2 Main Relay Check
1) Turn OFF ignition switch and remove main relay (1).
2) Check for proper connection to main relay (1) at terminal
3 and 4.
3) Check resistance between each two terminals. See Fig. 1
and 2.
Between terminals 1 and 2: Infinity
Between terminals 3 and 4: 70 – 110 Ω
4) Check that there is continuity between terminals 1 and 2
when battery is connected to terminals 3 and 4. See Fig. 3.
Is main relay in good condition?
3 Fuse Check
Is main "FI" fuse in good condition? See Fig. 4.
4 ECM Power Circuit Check
1) Turn OFF ignition switch, disconnect connectors from ECM
and install main relay.
2) Check for proper connection to ECM at terminals E23-6,
E22-10, E22-5 and E22-6.
3) If OK, then measure voltage between terminal E23-6 and
ground, E22-10 and ground with ignition switch ON.
Is each voltage 10 – 14 V?
Malfunction indicator lamp in combination meter
Relay
box
ACTION
Main
relay
E23-1
YES
Go to Step 5.
Go to Step 3.
Go to Step 4.
Go to Step 5.
NO
Go to Step 2.
Replace main
relay.
Check for short in
circuits connected
to this fuse.
"B/W", "B/Y" or
"Bl/B" circuit
open.