Isuzu 2008MY N Series Workshop Manual page 187

1A-184 Engine Control System (4HK1)
Circuit/ System Testing DTC P0428
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. Monitor the DTC Information with a scan tool.
Is DTC P0697 also set?
1. Start the engine and fully warm up (allow
engine coolant temperature to reach at least
80°C [176°F]).
2. Accelerate the engine between idle and
W.O.T. (accelerator pedal full travel) many
3
times while
Temperature Sensor 1 parameter with a scan
tool.
Is the Exhaust
parameter more than the specified value?
1. Turn OFF the ignition.
2. Disconnect the exhaust temperature sensor 1
harness connector.
3. Connect a DMM between the signal circuit
4
(pin 1 of J-34) and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified
value?
Important: The exhaust temperature sensor 1 may
be damaged if the sensor signal circuit is shorted to
a voltage source.
1. Test the signal circuit between the ECM (pin
73 of J-14) and the exhaust temperature
5
sensor 2 (pin 2 of J-34) for a short to battery or
ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Connect a 3-amp fused jumper wire between the
signal circuit and the low reference circuit (pins 1
and 2 of J-34).
6
Is the Exhaust
parameter less than the specified value?
Connect a 3-amp fused jumper wire between the
signal circuit (pin 2 of J-34) and a known good
ground.
7
Is the Exhaust
parameter less than the specified value?
Action
observing the Exhaust
Temperature Sensor
Temperature Sensor
Temperature Sensor
Value(s)
—
—
Go to DTC P0697
4.8 volts
1
5.5 volts
—
0.1 volts
1
0.1 volts
1
Yes
Go to Diagnostic
System Check -
Go to Step 2 Engine Controls
Go to Step 3
Go to Diagnostic
Go to Step 4
Go to Step 5 Go to Step 6
Go to Step 15 Go to Step 14
Go to Step 10 Go to Step 7
Go to Step 9 Go to Step 8
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