Isuzu N 2008 Series Workshop Manual page 179

1A-176 Engine Control System (4JJ1)
Step
Notice: The exhaust temperature sensor 2 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
9
ECM (pin 79 of J14) and the exhaust
temperature sensor 2 (pin 1 of J35) 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
74 of J14) and the exhaust temperature
sensor 2 (pin 2 of J35) for a short to any 5
10 volts 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
exhaust temperature sensor 2 (pins 1 and 2 of
11 J35).
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 74 and 79 of J14).
4. Repair the connection(s) as necessary.
Did you find and correct the condition?
Replace the exhaust temperature sensor 2. Refer
to Exhaust Temperature Sensor in Section 1G
13
Engine Exhaust.
Did you complete the replacement?
Important:
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 and fully warm up (allow
engine coolant temperature to reach at least
80°C [176°F]).
15
5. Accelerate the engine between idle and
W.O.T. (accelerator pedal full travel) many
times while
Temperature Sensor 2 parameter with a scan
tool.
Is the Exhaust Temperature Sensor 2 parameter
more than the specified value?
Action
Replacement ECM
all previously disconnected
observing the
Value(s)
—
—
—
—
—
must be
—
4.8 volts
Exhaust
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 4 Go to Step 16
No
—
—