Isuzu N 2008 Series Workshop Manual page 93

1A-90 Engine Control System (4JJ1)
Step
1. Inspect the following conditions:
• Restricted air cleaner element, restricted
or collapsed air tubing between the air
cleaner and the intake manifold
• Any air induction leak
• Any contamination or objects that block
the MAF sensor inlet
• Skewed or slow MAF sensor
• Any water intrusion in the induction
system
• Any type of restriction in the exhaust
2
system
• A sticking intake throttle valve
• A sticking EGR valve
• A sticking turbocharger nozzle control
actuator or solenoid valve
• Exhaust throttle valve or exhaust brake
valve for stack condition. Refer to
Exhaust System in Section 1G Engine
Exhaust.
2. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect
connector.
3. Inspect
connections and corrosion at the harness
connector of the MAF sensor (pins 1, 2 and 3
of J38).
3
4. Disconnect the ECM harness connector.
5. Inspect
connections and corrosion at the harness
connector of the ECM (pins 22, 23 and 69 of
J14).
6. Repair the connection(s) as necessary.
Did you find and correct the condition?
1. Test each sensor circuit between the ECM
(pins 22, 23 and 69 of J14) and the MAF
sensor (pins 1, 2 and 3 of J38) for high
4 resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Replace the MAF sensor. Refer to MAF/ IAT
Sensor in Section 1J Induction.
5
Did you complete the replacement?
Action
the MAF sensor
for an intermittent,
for an intermittent,
Value(s)
—
harness
for poor
—
for poor
—
—
Yes
Go to Step 6 Go to Step 3
Go to Step 6 Go to Step 4
Go to Step 6 Go to Step 5
Go to Step 6
No
—