Isuzu 2008MY N Series Workshop Manual page 335

1A-332 Engine Control System (4HK1)
Step
1. Connect a test lamp across the exhaust brake
solenoid valve harness connector (pins 1 and
2 of J-26).
2. Perform the Exhaust Brake Control with a
20
scan tool.
3. Command the solenoid ON and OFF.
Does the test lamp turn ON and OFF with
each command?
Does the test lamp remain illuminate with
21
each command?
Repair the open circuit or high resistance between
the ECM MAIN (15A) fuse and the solenoid valve
22
(pin 1 of J-26).
Did you complete the repair?
1. Test the control circuit between the ECM (pin
15 of J-14) and the solenoid valve (pin 2 of J-
26) for the following conditions:
• An open circuit
23
• A short to battery or ignition voltage
• High resistance
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the control circuit between the ECM (pin
15 of J-14) and the solenoid valve (pin 2 of J-
26) for a short to ground.
24
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Inspect for an intermittent and for poor
connections at the harness connector of the
solenoid valve (pins 1 and 2 of J-26).
25
2. Repair the connection(s) as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor
connection at the harness connector of the
26
ECM (pin 15 of J-14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the exhaust brake solenoid valve.
27
Did you complete the replacement?
Important:
programmed and learned.
28
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Reconnect
components, fuse or harness connector(s).
29
Did you complete the action?
Action
Replacement ECM
all previously disconnected
Value(s)
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must be
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Yes
Go to Step 25 Go to Step 21
Go to Step 24 Go to Step 23
Go to Step 29
Go to Step 29 Go to Step 26
Go to Step 29
Go to Step 29 Go to Step 27
Go to Step 29 Go to Step 28
Go to Step 29
Go to Step 29
Go to Step 3
No
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