Isuzu 1999 RODEO Workshop Manual page 800

Step
1 Was the "On–Board Diagnostic (OBD) System Check"
performed?
2 Are any DTCs set other than P0171?
3 1. Start the engine and operate the vehicle in "Closed
Loop".
2. Observe the "BANK 1 L.T. FUEL TRIM" and display
on the Tech 2.
Are the displayed values greater than the specified
values?
4 1. Review and record the Tech 2 Failure Records data.
2. Clear the Diagnostic Trouble Code P0171 and
operate the vehicle to duplicate the Failure Records
conditions.
3. Monitor the Tech 2 "Diagnostic Trouble Code" info
for Diagnostic Trouble Code P0171 while operating
the vehicle to duplicate the Failure Records
conditions.
4. Continue operating the vehicle until the Diagnostic
Trouble Code P0171 test runs and note the test
result.
Does the Tech 2 indicate Diagnostic Trouble Code
P0171 failed this ignition?
5 Visually and physically inspect the vacuum hoses for
disconnects, splits, kinks, improper routing and
improper connections and repair any problem found.
Did your inspection reveal a problem requiring repair?
6 Visually and physically inspect the crankcase
ventilation valve for proper installation and repair any
problem found (refer to Crankcase Ventilation
System).
Did your inspection reveal a problem requiring repair?
7 Start the engine and note the idle quality.
Is a high or unsteady idle being experienced?
8 With the engine idling, observe the "IDLE AIR
CONTROL" display on the Tech 2.
Is the displayed value above the specified value?
9 1. Visually and physically inspect the throttle body,
intake manifold, EGR valve and the EGR feed pipe
for vacuum leaks.
2. Repair any vacuum leaks as necessary.
Did your inspection reveal a vacuum leak?
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DTC P0171 – System Too Lean (Bank 1)
Action Value(s) Yes
— Go to Step 2
Go to the
applicable
DTC charts
and repair the
other DTCs
before
proceeding
with this
—
chart.
L.T. Fuel
Trim: 20% Go to Step 5
— Go to Step 5
— Verify repair
— Verify repair
— Go to Step 8
Above 5
Go to Step
counts 10
— Verify repair
6E1–173
No
Go to OBD
System
Check
Go to Step 3
Go to Step 4
The lean
condition is
not present. If
a driveability
symptom still
exists, refer
to Symptoms
section.
Go to Step 6
Go to Step 7
Go to Step
10
Go to Step 9
Go to Step
10