Isuzu 2008MY N Series Workshop Manual page 327

1A-324 Engine Control System (4HK1)
Step
1. Turn OFF the ignition.
2. Replace the glow relay with the starter relay or
replace with a known good relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the metal bus
bar (glow plug power supply E-14 connector)
and a known good ground.
5
5. Perform the Glow Relay Control with a scan
tool.
6. Command the relay ON while observing the
test lamp.
Does the test lamp turn ON only when
commanded ON?
Inspect the Glow (60A) slow blow fuse in the
chassis side fuse & relay box.
6
Is the Glow (60A) slow blow fuse open?
Replace the Glow (60A) slow blow fuse. If the slow
blow fuse continues to open, repair the short to
ground on a circuit fed by the slow blow fuse or
7
check for a shorted attached component.
Did you complete the repair?
1. Turn OFF the ignition.
2. Remove the glow relay.
3. Probe the battery voltage feed circuit of the
8
relay (pin 1 of X-19) with a test lamp that is
connected to a known good ground.
Does the test lamp illuminate?
1. Probe the voltage supply circuit of glow plugs
(pin 2 of X-19) with a test lamp that is
connected to a known good ground.
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2. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
Repair the open circuit or high resistance between
the Glow (60A) slow blow fuse and the glow relay
10
(pin 1 of X-19).
Did you complete the repair?
Repair the open circuit or high resistance between
the glow relay (pin 2 of X-19) and the glow plugs
11
(E-14 terminal).
Did you complete the repair?
Important: The glow plugs may be burnt out if the
battery voltage supply circuit is shorted to a voltage
source.
Repair the short to battery or ignition voltage
12
between the glow relay (pin 2 of X-19) and the glow
plugs (E-14 terminal).
Did you complete the repair?
Action Value(s) Yes
—
Go to Step 13
—
Go to Step 7
—
Go to Step 16
—
Go to Step 9
—
Go to Step 12
—
Go to Step 16
—
Go to Step 16
—
Go to Step 16
No
Go to Step 6
Go to Step 8
—
Go to Step 10
Go to Step 11
—
—
—