Isuzu N 2008 Series Workshop Manual page 287

1A-284 Engine Control System (4JJ1)
Step
Connect a test lamp between the low reference
circuit (pin 1 of E34) and battery voltage.
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Does the test lamp illuminate?
Important: The vacuum 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
92 of E12) and the vacuum pressure sensor
(pin 2 of E34) for the following conditions:
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• 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 vacuum 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 109 of E12) and the vacuum
pressure sensor (pin 1 of E34) 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 poor
connections at the harness connector of the
vacuum pressure sensor (pin 1 of E34).
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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 109 of E12).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the vacuum pressure sensor. Refer to
Vacuum Pressure Sensor in Section 1J Induction.
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Did you complete the replacement?
Important:
programmed and learned.
11
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Action
Replacement ECM
Value(s)
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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 11
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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