Isuzu 2000 Trooper Workshop Manual page 1190

Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 1. Ignition "ON," engine "OFF", review and record
Tech 2 Failure Records Data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor "DTC" info for DTC P0406
until the DTC P0406 test runs. Note the result.
Does the Tech 2 indicates DTC P0406 failed this
ignition?
3 1. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
4 Repair the damaged pin or terminal.
Is the action complete?
5 1. Disconnect the EGR harness connector.
2. Ignition "ON".
3. At the EGR valve, use a DVM to check the voltage
at the 5 volt reference wire (RED/YEL).
Did the DVM indicate the specified value?
6 1. Ignition "ON".
2. At the PCM connector, backprove with a DVM at the
5 volt reference for the EGR valve.
Did the DVM indicate the specified value?
7 Repair the open 5 volt reference circuit
Is the action complete?
8 1. Ignition "OFF"
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between 5 V
reference and Sensor Ground at EGR sensor
terminals.
NOTE: J-35616 Connector Test Adapter Kit may be
useful for gaining access to the recessed pins on the
valve.
Was the measured resistance in range?
9 1. Ignition "OFF".
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between
Sensor Ground and Signal wire at EGR sensor
terminal.
Is there an open circuit?
10 1. Ignition "OFF".
2. Disconnect the EGR harness at PCM connector.
3. Use a DVM to check for shorted wire between S37
and F53.
Is there a shorted wire?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 – EGR High Voltage
Action Value(s) Yes
— Go to Step 2
— Go to Step 3
Go to Step 4
—
— Verify repair
Go to Step 8
4–6 V
4–6 V Go to Step 7
— Verify repair
5 to 5 Km Go to Step 9
— Go to Step 15
— Go to Step 14
6E–321
No
Go to OBD
System
Check
Refer to
Diagnostic
Aids
Go to Step 5
Is the action
complete?
Go to Step 6
Go to Step 16
—
Go to Step 15
Go to Step 10
Go to Step 11