Isuzu 2008MY N Series Workshop Manual page 343

1A-340 Engine Control System (4HK1)
Step
1. Turn OFF the ignition.
2. Remove the bezel surrounding the IP cluster
enough to disconnect the DPD switch.
3. Disconnect
connector.
15
4. Connect a test lamp between the voltage feed
circuit of the DPD switch harness (pin 1 of B-
165) and a known good ground.
5. Start the engine.
Does the test lamp illuminate?
Observe the DPD Switch parameter with a scan
tool while momentarily jumping 3-amp fused
jumper wire across the switch harness connector
between pins 1 and 2 of B-165.
16
Does the scan tool indicate ON when the
circuit is jumpered and OFF when the circuit is
not jumpered?
Repair the open circuit or high resistance between
the ECM (10A) fuse and the switch (pin 1 of B-165).
17
Check the ECM (10A) fuse first.
Did you complete the repair?
1. Test the signal circuit between the ECM (pin
47 of J-14) and the switch (pin 2 of B-165) for
the following conditions:
• An open circuit
18
• A short to battery or ignition voltage
• High resistance
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
switch (pins 1 and 2 of B-165).
19
2. Repair the connection(s) as necessary.
Did you find and correct the condition?
1. Inspect for an intermittent, for a poor
connection and corrosion at the harness
connector of the ECM (pin 47 of J-14).
20
2. Repair the connection(s) as necessary.
Did you find and correct the condition?
Repair or replace the DPD switch.
21
Did you complete the repair or replacement?
Important:
programmed and learned.
22
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Action
the DPD switch
Replacement ECM
Value(s)
harness
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must be
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Yes
Go to Step 16 Go to Step 17
Go to Step 19 Go to Step 18
Go to Step 23
Go to Step 23 Go to Step 20
Go to Step 23 Go to Step 21
Go to Step 23 Go to Step 22
Go to Step 23
Go to Step 23
No
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