Isuzu 2008MY N Series Workshop Manual page 297

1A-294 Engine Control System (4HK1)
Step
Important: The exhaust differential pressure
sensor may be damaged if the sensor signal circuit
is shorted to a voltage source.
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
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following conditions:
• A short to battery or ignition voltage
• A short to any 5 volts reference
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Notice: The exhaust differential pressure sensor
shares the low reference circuit with other sensors.
A fault condition in the low reference circuit may set
DTCs on sensors that share this circuit.
1. Test the low reference circuit between the
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ECM (pin 79 of J-14) and the exhaust
differential pressure sensor (pin 1 of J-33) for
an open circuit or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Inspect for an intermittent and for a poor
connection at the harness connector of the
exhaust differential pressure sensor (pin 1 of
J-33).
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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
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ECM (pin 79 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.
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Refer to Exhaust Differential Pressure Sensor in
Section 1G Engine Exhaust.
Did you complete the replacement?
Important:
programmed and learned.
12
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Action
exhaust
Replacement ECM
Value(s)
—
—
—
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differential
—
must be
—
Yes
Go to Step 13 Go to Step 12
Go to Step 13 Go to Step 10
Go to Step 13 Go to Step 11
Go to Step 13 Go to Step 12
Go to Step 13
Go to Step 13
No
—
—