Isuzu N 2008 Series Workshop Manual page 106

Step
Notice: The IAT 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
ECM (pin 60 of J14) and the IAT sensor (pin 5
9
of J38 [Euro 4 specification] or pin 2 of J217
[expect Euro 4 specification]) 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
72 of J14) and the IAT sensor (pin 4 of J38
[Euro 4 specification] or pin 1 of J217 [expect
Euro 4 specification]) for a short to any 5 volts
10
reference circuit.
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
IAT sensor (pins 4 and 5 of J38 [Euro 4
specification] or pins 1 and 2 of J217 [expect
11
Euro 4 specification]).
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
12
ECM (pins 60 and 72 of J14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the MAF sensor or the IAT sensor. Refer
to MAF/ IAT Sensor in Section 1J Induction.
13
Did you complete the replacement?
Important: Replacement
programmed and learned.
14
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.
15
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.
16
Are there any DTCs that you have not diagnosed?
Action
ECM must
all previously disconnected
the conditions that
Engine Control System (4JJ1)
Value(s)
—
—
—
—
—
be
—
—
you
—
Yes
Go to Step 15 Go to Step 12
Go to Step 15 Go to Step 11
Go to Step 15 Go to Step 13
Go to Step 15 Go to Step 14
Go to Step 15
Go to Step 15
Go to Step 3 Go to Step 16
Go to DTC List
1A-103
No
—
—
System OK