Isuzu 1999 RODEO Workshop Manual page 1462

DTC P0171 –Fuel Trim System Lean Bank 1
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 Are any DTCs set other than P0171 and P0174?
3 1. Start the engine and operate the vehicle in "closed
loop."
2. Observe the "B1 Long Term Fuel Trim" display on
the Tech 2.
Is the displayed value greater than the specified value?
4 1. Review and record the Tech 2 Failure Records data.
2. Clear the DTC P0171/P0174 and operate the
vehicle to duplicate the Failure Records conditions.
3. Monitor the Tech 2 "DTC" info for DTC P0171 while
operating the vehicle to duplicate the Failure
Records conditions.
4. Continue operating the vehicle until the DTC P0171
test runs and note the test result.
Does the Tech 2 indicate DTC P0171 failed this
ignition?
5 Was DTC P0174 also set?
6 Visually and physically inspect the vacuum hoses for
disconnections, splits, kinks, improper routing and
improper connections and repair any problem found.
Did your inspection reveal a problem requiring repair?
7 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?
8 1. Inspect the MAF sensor inlet screen for damage or
for the presence of foreign objects which may
partially block the air flow sample through the MAF
sensor.
2. Correct any problem that is found as necessary.
Did your inspection of the MAF sensor reveal a
condition requiring repair?
9 Start the engine and note the idle quality.
Is a high or unsteady idle being experienced?
10 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 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS
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
— Go to Step 6
— Verify repair
— Verify repair
— Verify repair
— Go to Step 10
— Verify repair
6E2–219
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 15
Go to Step 7
Go to Step 8
Go to Step 9
Go to Step11
Go to Step 11