Isuzu 2008MY N Series Workshop Manual page 295

1A-292 Engine Control System (4HK1)
Step
Connect a 3-amp fused jumper wire between the 5
volts reference circuit and the signal circuit (pins 2
and 3 of J-33).
5
Is the Exhaust Differential Pressure Sensor
parameter more than the specified value?
1. Test the 5 volts reference circuit between the
ECM (pin 80 of J-14) and the exhaust
differential pressure sensor (pin 3 of J-33) for
an open circuit or high resistance.
6
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the signal circuit between the ECM (pin
67 of J-14) and the exhaust differential
pressure sensor (pin 2 of J-33) for the
following conditions:
• An open circuit
7 • A short to ground
• A short to the low reference circuit
• 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
exhaust differential pressure sensor (pins 2
and 3 of J-33).
8
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 poor
connections at the harness connector of the
9
ECM (pins 67 and 80 of J-14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Important: Replacement
pressure sensor must be learned.
Replace the exhaust differential pressure sensor.
10
Refer to Exhaust Differential Pressure Sensor in
Section 1G Engine Exhaust.
Did you complete the replacement?
Important:
programmed and learned.
11
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Action
exhaust
Replacement ECM
Value(s)
4.5 volts
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differential
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must be
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Yes
Go to Step 8 Go to Step 7
Go to Step 12 Go to Step 9
Go to Step 12 Go to Step 9
Go to Step 12 Go to Step 10
Go to Step 12 Go to Step 11
Go to Step 12
Go to Step 12
No
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