Isuzu 2000 Trooper Workshop Manual page 989

6E–120
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Exhaust Gas Recirculation (EGR) System Check
Step
1 Check the EGR valve for looseness.
Is the EGR valve Loose?
2 Tighten the EGR valve.
Is the action complete?
3 1. Place the transmission selector in Park or Neutral.
2. Start the engine and idle until warm.
3. Using a Tech 2, command EGR "50% ON."
(Refer to the Miscellaneous Test.)
Does the engine idle rough and lose RPMs?
4 1. Engine "OFF."
2. Ignition "ON."
3. Using a test light to ground, check the EGR harness
between the EGR valve and the ignition feed.
Does the test light illuminate?
5 Repair the EGR harness ignition feed.
Was the problem corrected?
6 1. Remove the EGR valve.
2. Visually and physically inspect the EGR valve
pintle, valve passages and adapter for excessive
deposits, obstructions or any restrictions.
Does the EGR valve have excessive deposits,
obstructions or any restrictions?
7 Clean or replace EGR system components as
necessary.
Was the problem corrected?
8 1. Ground the EGR valve metal case to battery (–).
2. Using a Tech 2, command EGR "ON" and observe
the EGR valve pintle for movement.
Does the EGR valve pintle move according to
command?
9 1. Remove the EGR inlet and outlet pipes from the
intake and exhaust manifolds.
2. Visually and physically inspect manifold EGR ports
and EGR inlet and outlet pipes for blockage or
restriction caused by excessive deposits or other
damage.
Do the manifold EGR ports or inlet and outlet pipes
have excessive deposits, obstructions, or any
restrictions?
10 Clean or replace EGR system components as
necessary.
Is the action complete?
Action Value(s) Yes
Go to Step 2
—
— Verify repair
EGR system
working
properly. No
problem
— found.
— Go to Step 6
— Verify repair
— Go to Step 7
— Verify repair
— Go to Step 9
— Go to Step 10
— Verify repair
No
Go to Step 3
—
Go to Step 4
Go to Step 5
Go to Step 6
Go to Step 8
Go to Step 8
Go to DTC
P1406 chart
EGR system
working
properly. No
problem
found.
—