Isuzu N 2008 Series - Page 170

Engine Control System (4JJ1) 1A-167
Circuit/ System Testing DTC P0428
4
1. Turn OFF the ignition.
2. Disconnect the exhaust temperature sensor 1
harness connector.
3. Turn ON the ignition, with the engine OFF.
Is the Exhaust Temperature Sensor 1 parameter
more than the specified value?
4.5 volts
Go to Step 6 Go to Step 5
5
1. Test the signal circuit between the ECM (pin
73 of J14) and the exhaust temperature
sensor 1 (pin 2 of J34) for the following
conditions:
• A short to ground
• A short to the low reference circuit
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
—
Go to Step 9 Go to Step 7
6
Replace the exhaust temperature sensor 1. Refer
to Exhaust Temperature Sensor in Section 1G
Engine Exhaust.
Did you complete the replacement?
—
Go to Step 9 —
7
1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect connections at the harness connector
of the ECM (pins 73 and 79 of J14) for
corrosion.
4. Repair or clean the connection(s) as
necessary.
Did you find and correct the condition?
—
Go to Step 9 Go to Step 8
8
Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
—
Go to Step 9 —
9
1. Reconnect all previously disconnected
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition?
—
Go to Step 3 Go to Step 10
10
Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed?
—
Go to DTC List System OK
Step Action Value(s) Yes No
Step Action Value(s) Yes No
1
Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2
Go to Diagnostic
System Check -
Engine Controls
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