Isuzu N 2008 Series Workshop Manual page 285

1A-282 Engine Control System (4JJ1)
Step
1. Turn OFF the ignition.
2. Disconnect the vacuum hose from the vacuum
pressure sensor or turbocharger nozzle
control solenoid.
4
3. Start the engine.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition?
1. Turn OFF the ignition.
2. Disconnect the vacuum pressure sensor
harness connector.
3. Connect a DMM between the 5 volts reference
5
circuit of the sensor harness (pin 3 of E34)
and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified value?
1. Connect a 3-amp fused jumper wire between
the 5 volts reference circuit and the signal
circuit (pins 3 and 2 of E34).
6
2. Monitor the DTC Information with a scan tool.
Is DTC P2528 set, but not DTC P2527?
Notice: The vacuum pressure sensor shares the 5
volts reference circuit with other sensors. A fault
condition in the 5 volts reference circuit may set
DTCs on sensors that share this circuit.
1. Test the 5 volts reference circuit between the
7
ECM (pin 95 of E12) and the vacuum pressure
sensor (pin 3 of E34) for an open circuit or
high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
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:
• An open circuit
• A short to ground
8
• 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
vacuum pressure sensor (pins 2 and 3 of
9 E34).
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
10
ECM (pins 92 and 95 of E12).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Action Value(s) Yes
—
Go to Step 5
4.5 volts
Go to Step 6
—
Go to Step 9
—
Go to Step 14
—
Go to Step 14
—
Go to Step 14
—
Go to Step 14
No
Go to Step 11
Go to Step 7
Go to Step 8
Go to Step 10
Go to Step 10
Go to Step 12
Go to Step 13