Isuzu N 2008 Series Workshop Manual page 322

Step
1. Turn OFF the ignition.
2. Remove the bezel surrounding the IP cluster
enough to disconnect the DPD regeneration
switch.
3. Disconnect the DPD regeneration switch
harness connector.
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4. Connect a test lamp between the voltage feed
circuit of the DPD regeneration switch harness
(pin 1 of B165) and a known good ground.
5. Start the engine.
Does the test lamp illuminate?
Observe the DPD Regeneration 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 B165.
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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 2 of B165).
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Check the ECM (10A) fuse first.
Did you complete the repair?
1. Test the signal circuit between the ECM (pin
47 of J14) and the switch (pin 2 of B165) for
the following conditions:
• An open circuit
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• 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 B165).
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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 J14).
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2. Repair the connection(s) as necessary.
Did you find and correct the condition?
Repair or replace the DPD regeneration switch.
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Did you complete the repair or replacement?
Important: Replacement
programmed and learned.
22
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Action
ECM must
Engine Control System (4JJ1)
Value(s)
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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
1A-319
No
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