Isuzu Trooper (1998-2002 year). Manual — part 333
6E–245
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1171 Fuel System Lean During Acceleration
060RW193–1
Circuit Description
The powertrain control module (PCM) internal circuitry
can identify if the vehicle fuel system is capable of
supplying adequate amounts of fuel during heavy
acceleration (power enrichment). The PCM monitors the
voltage of the oxygen sensor during power enrichment.
When a power enrichment mode of operation is
requested during “closed loop” operation (by heavy
acceleration), the PCM will provide more fuel to the
engine. Under these conditions the PCM should detect a
“rich” condition (high oxygen sensor voltage). If this “rich”
exhaust is not detected at this time, a DTC P1171 will set.
A plugged fuel filter, restricted fuel line, restricted in-tank
filter or defective fuel pump can prevent adequate
amounts of fuel from being supplied during power
enrichment mode.
Conditions for Setting the DTC
D
No related DTCs.
D
Engine is operating in “closed loop power enrichment”
mode for 3 seconds.
D
Engine coolant temperature is above 60
°
C (140
°
F).
D
While in “power enrichment” mode the oxygen sensor
voltage remains below 400 mV for 3 seconds.
Action Taken When the DTC Sets
D
The PCM will illuminate the malfunction indicator lamp
(MIL) the first the fault 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
DTC P1171 can be cleared by using Tech 2 “Clear Info”
function or by disconnecting the PCM battery feed.
Diagnostic Aids
D
A restricted fuel filter or fuel line, restricted in-tank filter,
or a defective fuel pomp may supply adequate
6E–246
ENGINE DRIVEABILITY AND EMISSIONS
amounts of fuel at idle, but may not be able to supply
enough fuel during heavy acceleration.
D
Water or alcohol in the fuel may cause low HO2S
voltage during acceleration.
D
Check for faulty or plugged fuel injector(s).
D
Check for low fuel.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
4. When the engine is idling or at steady cruise, the
HO2S voltage should vary from between
approximately 100 mV to 900 mV. It is possible to
measure a satisfactory fuel pressure at idle even
though the pressure may drop at high flow
requirements. It may be necessary to watch fuel
pressure at high engine load.
5. Wrap a shop towel around the fuel pressure
connector to absorb any small amount of fuel
leakage that may occur when installing gauge.
Ignition “ON,” pump pressure should be 280-320
kPa.
DTC P1171 – Fuel System Lean During Acceleration
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 component-related DTCs set?
—
Go to
component
DTC charts
Go to
Step 3
3
1. Check the vehicle’s fuel tank for an adequate
amount of fuel.
2. Add fuel to the vehicle’s fuel tank if the tank is almost
empty.
Was fuel added to the vehicle’s fuel tank?
—
Go to
Step 4
Go to
Step 5
4
1. Place the transmission in park.
2. Using Tech 2, observe HO2S 1 voltage while
running warm engine 75
°
C-95
°
C (167
°
F-203
°
F) at
1200 RPM.
3. HO2S 1 voltage should vary within the specified
range.
4. Quickly open the throttle halfway for a few seconds.
Did the voltage suddenly rise toward the high end of the
specified range?
100-900 mV
Go to Chart
A-7
Go to
Step 5
5
1. Disconnect the fuel pump relay and crank the
engine to relieve the fuel pressure.
2. Install the fuel pressure gauge.
3. Start the engine and idle at normal operating
temperature.
4. Disconnect the vacuum line going to the fuel
pressure regulator.
With the engine running, is the fuel pressure within the
specified range?
280-325 kPa
(41-46 psi)
Go to
OBD
System
Check
Go to
Step 6
6
Check for restricted fuel lines or restricted in-line filter.
Was a problem found?
—
Verify repair
Go to
Step 7
6E–247
ENGINE DRIVEABILITY AND EMISSIONS
DTC P1171 – Fuel System Lean During Acceleration
(Cont'd)
Step
No
Yes
Value(s)
Action
7
1. Ignition “OFF.”
2. Remove the fuel pump relay and replace it with a
fused jumper which will connect the relay’s battery
terminal to the terminal leading to the fuel pump
fuse.
3. While the fuel pump is operating, use pliers to slowly
close the return line (do not exceed the first
specified value).
Using the pliers to restrict the return line, can the fuel
pressure be manipulated to exceed the second
specified value?
414 kPa
(60 psi)
325 kPa
(46 psi)
Go to
Diagnostic
Aids
Go to
Step 8
8
Check for:
D
Faulty fuel pump
D
Restricted fuel pump strainer (sock)
D
Incorrect fuel pump
D
Incorrect fuel being used
D
Hot fuel
Is the action complete?
—
Verify repair
—
6E–248
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1380 ABS Rough Road ABS System Fault
Circuit Description
The powertrain control module (PCM) monitors ABS fault
signal. When PCM receives fault signal, PCM will set
DTC P1380.
Conditions for Setting the DTC
D
Vehicle speed is more than 5 mph.
D
Load is less than 99%.
D
Engine revolution is less than 6250 rpm.
D
PCM receives ABS fault signals from ABS unit.
D
Ignition on.
D
Misfire DTCs exist.
D
100 test failures within 120 test samples.
Action Taken When the DTC Sets
D
The PCM will store DTC 1380 only, no MIL turn on.
Conditions for Clearing the MIL/DTC
D
A history DTC P1380 will clear after 40 consecutive
warm-up cycles have occurred without a fault.
D
DTC 1380 can be cleared by using Tech-2 or
disconnecting the PCM battery feed.
Diagnostic Aids
Check for the following conditions:
D
PCM and ABS communication line short circuit to other
line may cause faulty signal. Inspect communication
line.
D
Follow ABS ECU diagnosis procedure, refer to ABS
procedure page.
DTC P1380 – ABS Rough Road ABS System Fault
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
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 “Specific DTC” info for DTC
P1380 and Misfire DTCs until the DTC P1380 and
Misfire DTCs test runs. Note the result.
Does the Tech 2 indicates DTC P1380 and Misfire
DTCs failed this ignition?
—
Refer to ABS
diagnosis
After inspect
ABS, unit re-
peat
Step 2
Still problem
exists, go to
Step 3
Clear DTC by
Tech 2
3
Check short circuit among communication line of
PCM/ABS and others.
Was short circuit?
—
Repair wiring
Verify repair
Go to
Step 4
4
Replace the PCM.
IMPORTANT: The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?
—
Verify repair
—
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст