Isuzu N 2008 Series Workshop Manual page 97

1A-94 Engine Control System (4JJ1)
Circuit/ System Testing DTC P0103
Step
Did you perform the Diagnostic System Check -
1 Engine Controls?
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
2
4. Observe the Mass Air Flow (MAF) Sensor
parameter with a scan tool.
Is the MAF Sensor parameter more than the
specified value?
Monitor the DTC Information with a scan tool.
3
Is DTC P0560 also set?
1. Turn OFF the ignition.
2. Disconnect
connector.
4
3. Turn ON the ignition, with the engine OFF.
Is the MAF Sensor parameter less than the
specified value?
1. Turn OFF the ignition.
2. Disconnect
connector.
5
3. Turn ON the ignition, with the engine OFF.
Is the MAF Sensor parameter less than the
specified value?
Connect a test lamp between the low reference
circuit (pin 2 of J38) and battery voltage.
6
Does the test lamp illuminate?
Important: The MAF sensor may be damaged if
the sensor signal circuit is shorted to a voltage
source.
1. Test the signal circuit between the ECM (pin
69 of J14) and the MAF sensor (pin 3 of J38)
for the following conditions:
7
• A short to battery or ignition voltage
• A short to the 12 volts reference
• A short to any 5 volts reference
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the low reference circuit between the
ECM (pin 22 of J14) and the MAF sensor (pin
2 of J38) for an open circuit or high resistance.
8
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Action
the MAF sensor harness
the MAF sensor harness
Value(s) Yes
—
Go to Step 2
4.9 volts
Go to Step 3
—
Go to Step 4
0.1 volts
Go to DTC P0560
0.1 volts
Go to Step 6
—
Go to Step 9
—
Go to Step 13
—
Go to Step 13
No
Go to Diagnostic
System Check -
Engine Controls
Go to Diagnostic
Aids
Go to Step 5
Go to Step 7
Go to Step 7
Go to Step 8
Go to Step 12
Go to Step 10