Isuzu 4HL1 Workshop Manual page 177

Step
Check the common rail pressure sensor
circuit harness for open wiring or short.
1. Starter switch "OFF".
2. Disconnect the ECM.
3. Disconnect the common rail pressure
sensor connector.
5
4. Measure the resistance at the ECM
connector.
Was the resistance within range?
Repair or replace the faulty harness.
6
Is the action complete?
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
7
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
Replace the common rail (common rail
pressure sensor).
8
Is the action complete?
Review the DTC.
1. Restore the vehicle.
2. Bleed the air from the fuel system.
9
3. Using Tech 2, clear the DTC.
4. Perform test run and review the DTC.
Is DTC115 detected?
Inspect the fuel system according to the
following procedures.
1. Check the fuel filter for excessive
contamination and choke.
2. Check high- and low-pressure pipes for
10
collapse, choke, and loose connection.
3. Check the feed pipe in the fuel tank for
foreign materials.
Is the fuel system sound?
Repair or replace the faulty portion(s).
11
Is the action complete?
Inspect the common rail.
1. Check the pressure limiter for fuel leak.
12
Is the common rail sound?
Replace the common rail.
13
Is the action complete?
Action
Engine Control System 1A-175
Value(s)
Pins 63-66/
67: ∞ Ω
Pins 66/67-
64: ∞ Ω
Pins 63-64:
∞ Ω
Pins 67-66:
0 Ω
Pins 26-63/
67/66/64: ∞ Ω
Pins 63/67/
66/64/26-
ground: ∞ Ω
Go to Step 7
Verify repair and
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go to Step 9
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Verify repair and
go to Step 9
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Verify repair and
go to Step 9
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Go to Step 10
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Go to Step 12
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Go to Step 15
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Go to Step 14
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Go to Step 15
Yes No
Go to Step 6
Repair is
complete
Go to Step 11
Go to Step 13
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