Isuzu N 2008 Series Workshop Manual page 96

Step
Connect a 3-amp fused jumper wire between the
12 volts reference circuit and the signal circuit (pins
1 and 3 of J38).
5
Is the MAF Sensor parameter more than the
specified value?
1. Test the 12 volts reference circuit between the
ECM (pin 23 of J14) and the MAF sensor (pin
1 of J38) 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
69 of J14) and the MAF sensor (pin 3 of J38)
for the following conditions:
• An open circuit
• A short to ground
7
• 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
MAF sensor (pins 1 and 3 of J38).
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 23 and 69 of J14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the MAF sensor. Refer to MAF/ IAT
Sensor in Section 1J Induction.
10
Did you complete the replacement?
Important: Replacement
programmed and learned.
11
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
1. Reconnect
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
12
5. Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition?
Observe the DTC Information with a scan tool.
13
Are there any DTCs that you have not diagnosed?
Action
ECM must
all previously disconnected
the conditions that
Engine Control System (4JJ1)
Value(s)
4.9 volts
—
—
—
—
—
be
—
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you
—
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
Go to Step 3 Go to Step 13
Go to DTC List
1A-93
No
—
—
System OK