Isuzu 4HL1 Workshop Manual page 60

1A-58 Engine Control System
Step
Repair or replace the harness between SBF
(ECM: 50A) and SBF (engine controller: 30A).
9
Is the action complete?
Check the main relay coil circuit for open
wiring.
1. Remove the main relay.
2. Disconnect the ECM.
10
3. Check the continuity between main relay
and ECM pin as well as main relay and
ground (e.g., frame or body).
Is the circuit in normal condition?
Repair or replace the faulty harness.
11
Is the action complete?
Check the circuit between main relay and
ECM for open wiring.
1. Remove the main relay.
2. Disconnect the ECM.
12
3. Check the continuity between main relay
and ECM pin.
Is the circuit in normal condition?
Repair or replace the faulty harness.
13
Is the action complete?
Check the ECM power ground circuit for open
wiring.
1. Disconnect the ECM.
14
2. Check the continuity between ECM pin
and ground (e.g., frame or body).
Is the circuit in normal condition?
Repair or replace the faulty harness.
15
Is the action complete?
Action Value(s)
—
Verify repair and
go to Step 10
Pins 4-
117/118:
Continued
(Main relay) -
(ECM)
Pin 3-ground:
Continued
(Main relay)
Go to Step 12
Verify repair and
—
go to Step 12
Pins 2-
114/115/116:
Continued
(Main relay) -
(ECM)
Go to Step 14
Verify repair and
—
go to Step 12
Pin 119/120/
121-ground:
Continued
Check is complete
—
Verify repair
Yes No
Go to Step 11
Go to Step 13
Go to Step 15
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