ENGINE GENERAL INFORMATION AND DIAGNOSIS (M13 ENGINE) 6-2-59
3 Main Relay Circuit Check
1) Turn ignition switch to OFF position.
2) Check for fuse blow at FI fuse (20 A). (See Fig. 1.)
3) If OK, measure voltage between “E23-15” wire terminal of
ECM connector and body ground.
Is voltage 10 – 14 V?
Go to Step 4. Go to Step 8.
4 Main Relay Circuit Check
1) Remove ECM from vehicle body and connect connectors
to ECM.
2) Turn ignition switch to ON position.
3) Measure voltage between “E23-15” wire terminal of ECM
connector and body ground.
Is voltage 0 – 1 V?
Go to Step 6. Go to Step 5.
5 ECM Ground Circuit Check
1) Turn ignition switch to OFF position.
2) Disconnect connectors from ECM.
3) Measure resistance between each “E22-1”, “E23-1” and
“E23-2” wire terminals of ECM connector and body
ground.
Is resistance 1
Ω
or less?
Substitute a
known-good ECM
and recheck.
“BLK/YEL” or
“BLK” wire open
circuit or high
resistance circuit.
6 Main Relay Circuit Check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Using service wire, ground “E23-15” wire terminal of ECM
connector and measure voltage between each “E21-5” and
“E21-6” wire terminals of ECM connector and body
ground.
Is voltage 10 – 14 V?
Substitute a
known-good ECM
and recheck.
Go to Step 7.
7 Main Relay Circuit Check
1) Remove main relay from relay box. (See Fig. 2.)
2) Check for proper connection to main relay connector at
“BLK/YEL” and “BLK/RED” wire terminals.
3) If OK, measure resistance between each “E21-5” and
“E21-6” wire terminals of ECM connector and “BLK/RED”
wire terminal of main relay connector.
Is resistance 1
Ω
or less?
Go to Step 8. “BLK/RED” wire
open circuit or
high resistance cir-
cuit.
8 Main Relay Circuit Check
1) Remove main relay from relay box.
2) Measure voltage between “BLK/YEL” wire terminals of
main relay connector and body ground.
Is voltage 10 – 14 V?
Go to Step 9. “BLK/YEL” wire cir-
cuit open.
Step Action Yes No