Isuzu 4HL1, Workshop Manual

Page: 177 / 267

Engine Control System 1A-175
5
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.
4. Measure the resistance at the ECM
connector.
Was the resistance within range?
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 Go to Step 6
6
Repair or replace the faulty harness.
Is the action complete?
—
Verify repair and
go to Step 9 —
7
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
—
Verify repair and
go to Step 9 —
8
Replace the common rail (common rail
pressure sensor).
Is the action complete?
—
Verify repair and
go to Step 9 —
9
Review the DTC.
1. Restore the vehicle.
2. Bleed the air from the fuel system.
3. Using Tech 2, clear the DTC.
4. Perform test run and review the DTC.
Is DTC115 detected?
—
Go to Step 10
Repair is
complete
10
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
collapse, choke, and loose connection.
3. Check the feed pipe in the fuel tank for
foreign materials.
Is the fuel system sound?
—
Go to Step 12 Go to Step 11
11
Repair or replace the faulty portion(s).
Is the action complete?
—
Go to Step 15 —
12
Inspect the common rail.
1. Check the pressure limiter for fuel leak.
Is the common rail sound?
—
Go to Step 14 Go to Step 13
13
Replace the common rail.
Is the action complete?
—
Go to Step 15 —
Step Action Value(s) Yes No