Isuzu Trooper (1998-2002 year). Manual — part 463
6E–222
6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0174 – Fuel Trim System Lean Bank 2
Step
Action
Value(s)
Yes
No
1
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—
Go to
Step 2
Go to
OBD
System
Check
2
Are any DTCs set other than P0174 and P0171?
—
Go to the
applicable
DTC charts
and repair the
other DTCs
before
proceeding
with this
chart.
Go to
Step 3
3
1. Start the engine and operate the vehicle in “closed
loop”.
2. Observe the “BANK 2 L.T. FUEL TRIM” display on
the Tech 2.
Is the displayed values greater than the specified
values?
L.T. Fuel
Trim: +20%
Go to
Step 5
Go to
Step 4
4
1. Review and record 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 P0174 while
operating the vehicle to duplicate the Failure
Records conditions.
4. Continue operating the vehicle until the DTC P0174
test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0174 failed this
ignition?
—
Go to
Step 5
The lean
condition is
not present.
If a
driveability
symptom still
exists, refer
to
Symptoms
section.
5
Was DTC P0171 also set?
—
Go to
Step 6
Go to
Step 15
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?
—
Verify repair
Go to
Step 7
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?
—
Verify repair
Go to
Step 8
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?
—
Verify repair
Go to
Step 9
9
Start the engine and note the idle quality.
Is a high or unsteady idle being experienced?
—
Go to
Step 10
Go to
Step 11
6E–223
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0174 – Fuel Trim System Lean Bank 2
(Cont'd)
Step
No
Yes
Value(s)
Action
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?
—
Verify repair
Go to
Step 11
11
Check the fuel for excessive water, alcohol, or other
contaminants (see
Diagnosis in Engine Fuel for
procedure) and correct the contaminated fuel condition
is present (see
Engine Fuel).
Was the fuel contaminated?
—
Verify repair
Go to
Step 12
12
1. Visually and physically inspect the PCM injector
grounds, power grounds and sensor grounds to
ensure that they are clean, tight, and in their proper
locations.
2. If a faulty ground condition is present, correct it as
necessary.
Did your inspection reveal a condition requiring repair?
—
Verify repair
Go to
Step 13
13
1. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in “closed loop” while
monitoring the “BANK 2 S.T. FUEL TRIM” displayed
on the Tech 2.
Does the “BANK 2 S.T. FUEL TRIM” value decrease to
near the specified value?
0%
Go to
Step 19
Go to
Step 14
14
Perform the procedure in the ”Fuel System Pressure
Test” and repair fuel system problem if necessary.
Did the Fuel System Pressure Test isolate a condition
requiring repair?
—
Verify repair
Go to
Step 15
15
1. Visually and physically inspect the intake manifold,
injector O-rings, EGR adapter, EGR valve and the
EGR feed pipes for vacuum leaks.
2. Repair any problem that is found.
Did your inspection reveal a problem?
—
Verify repair
Go to
Step 16
16
Visually and physically inspect the Bank 2 exhaust
manifold for leaks and loose or missing hardware and
correct any problem found.
Did your inspection reveal a problem?
—
Verify repair
Go to
Step 17
17
Perform the “Injector Balance Test” and correct any
problem found (refer to
Fuel Metering System).
Did the Injector Balance Test isolate a problem?
—
Verify repair
Go to
Step 18
18
1. Visually and physically inspect the Bank 2 HO2S 1
to ensure that it is installed securely and that the
Bank 2 HO2S 1 pigtail and wiring harness are not
contacting the exhaust or otherwise damaged.
2. If a problem is found, correct it as necessary.
Did your inspection reveal a problem?
—
Verify repair
Check the
Procedure
Refer to
Diagnostic
Aids
19
Replace the MAF sensor.
Is the action complete?
—
Verify repair
—
6E–224
6VE1 3.5 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0175 Fuel Trim System Rich Bank 2
D06R200010
Circuit Description
To provide the best possible combination of driveability,
fuel economy, and emission control, a “closed loop”
air/fuel metering system is used. While in “closed loop”,
the powertrain control module (PCM) monitors the Bank 1
HO2S 1 and Bank 2 HO2S 1 signals and adjusts fuel
delivery based upon the HO2S signal voltages. A change
made to fuel delivery will be indicated by the long and
short term fuel trim values which can be monitored with a
Tech 2. Ideal fuel trim values are around 0%; if the HO2S
signals are indicating a lean condition the PCM will add
fuel, resulting in fuel trim values above 0%. If a rich
condition is detected, the fuel trim values will be below
0%, indicating that the PCM is reducing the amount of fuel
delivered. If an excessively rich condition is detected on
Bank 2, the PCM will set DTC P0175.
The PCM’s maximum authority to control long term fuel
trim allows a range between –15%(automatic
transmission) or –12%(manual transmission) and +20%.
The PCM’s maximum authority to control short term fuel
trim allows a range between –11% and +20%. The PCM
monitors fuel trim under various engine speed/load fuel
trim cells before determining the status of the fuel trim
diagnostic.
Conditions for Setting the DTC
D
None of the following DTCs are set: idle system, EGR,
HO2S, (response, transition, open, low volts, no
activity), MAF, TPS, MAP, IAT, canister purge, EVAP,
injector circuit, or misfire.
D
Engine coolant temperature is between 6
°
C (42.8
°
F)
and 105
°
C (221
°
F).
D
Intake air temperature is between –40
°
C (–40
°
F) and
120
°
C (248
°
F).
D
Manifold absolute pressure is between 24 kPa and 99
kPa.
D
Throttle angle is steady between 3 and 95%.
D
Vehicle speed is below 136 km/h (85 mph).
D
Engine speed is between 400 and 6,000 RPM.
D
Barometric pressure is greater than 72.5 kPa.
D
Mass air flow is between 2 g/second and 200 g/second.
D
Ignition voltage is above 9.5 volts.
D
Fuel system is in “closed loop”.
Action Taken When the DTC Sets
D
The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
failure is detected.
D
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC
D
The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.
6E–225
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
D
A history DTC P0175 will clear after 40 consecutive
warm-up cycles have occurred without a fault.
D
DTC P0175 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
D
Poor connection at PCM – Inspect harness connectors
for backed -out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.
D
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Bank 2 HO2S 1 display on the Tech 2 while moving
connectors and wiring harnesses related to the engine
harness. A change in the display will indicate the
location of the fault.
Reviewing the Failure Records Vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. DTCs other than P0172 and P0175 may indicate a
condition present which may cause a lean condition.
If this is the case, repairing the condition which
caused the other DTC will most likely correct the
DTC P0172/P0175.
4. If the DTC P0175 test passes while the Failure
Records conditions are being duplicated, the rich
condition is intermittent. Refer to
Diagnostic Aids or
Symptoms for additional information on diagnosing
intermittent problems.
DTC P0175 – Fuel Trim System Rich Bank 2
Step
Action
Value(s)
Yes
No
1
Was the ”On-Board Diagnostic (OBD) System Check”
performed?
—
Go to Step 2
Go to
OBD
System
Check
2
Are any DTCs set other than P0172 and P0175?
—
Go to the
applicable
DTC charts
and repair the
other DTCs
before
proceeding
with this
chart.
Go to
Step 3
3
1. Start the engine and operate the vehicle in “closed
loop”.
2. Observe the “BANK 2 L.T. FUEL TRIM” display on
the Tech 2.
Is the displayed value more negative than the specified
value?
L.T. Fuel
Trim: –15%
(auto. trans.)
OR –12%
(man. trans.)
Go to
Step 5
Go to
Step 4
4
1. Review and record the Tech 2 Failure Records data.
2. Clear the DTC P0172/P0175 and operate the
vehicle to duplicate the Failure Records conditions.
3. Monitor the Tech 2 “DTC” info for DTC P0175 while
operating the vehicle to duplicate the Failure
Records conditions.
4. Continue operating the vehicle until the DTC P0175
test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0175 failed this
ignition?
—
Go to
Step 5
The rich
condition is
not present.
If a
driveability
symptom still
exists, refer
to
Symptoms.
5
Was DTC P0172 also set?
—
Go to
Step 6
Go to
Step 15
6
Visually and physically inspect the air filter element and
replace it if necessary.
Did the air filter require replacement?
—
Verify repair
Go to
Step 7
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст