Isuzu 2008MY N Series Workshop Manual page 177

1A-174 Engine Control System (4HK1)
Step
1. Remove the EGR valve assembly from the
engine.
2. Inspect the EGR valve for the following
conditions:
• Restricted
materials
4
• Excessive deposits at valve
• Bent valve shaft or valve
3. Repair or replace as necessary.
Did you find and correct the condition?
1. Turn OFF the ignition.
2. Disconnect the EGR valve harness connector.
3. Inspect
connections and corrosion at the harness
connector of the EGR valve (pins 1, 2, 3, 4, 5,
6, 7 and 8 of E-15).
4. Disconnect the ECM harness connector.
5. Inspect
5
connections and corrosion at the harness
connector of the ECM (pins 87, 93, 94, 99,
101, 103 110 and 111 of E-12).
6. Test for an open circuit or high resistance on
each circuit.
7. Repair the connection(s) or circuit(s) as
necessary.
Did you find and correct the condition?
1. Test the solenoid circuits between the ECM
(pins 103, 110 and 111 of E-12) and the EGR
valve (pins 6, 7 and 8 of E-15) for the following
conditions:
• A short to ground
• A short to battery or ignition voltage
6
• A short circut each other
• A short to the EGR position sensor
circuit(s)
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Replace the EGR valve. Refer to EGR Valve and
EGR Cooler in Section 1F Emission Control.
7
Did you complete the replacement?
Action
EGR valve by
for an intermittent,
for an intermittent,
Value(s)
foreign
—
for poor
for poor
—
—
—
Yes
Go to Step 8 Go to Step 5
Go to Step 8 Go to Step 6
Go to Step 8 Go to Step 7
Go to Step 8
No
—