Isuzu 2000 Trooper Workshop Manual page 1042

D MAF sensor –The system can go rich if MAF sensor
signal indicates an engine airflow measurement that is
not correct. Disconnect the MAF sensor to see it the
rich condition is corrected. If so, replace the MAF
sensor.
D Check for a leak in the fuel pressure regulator
diaphragm by checking the vacuum line to the
regulator for the presence of fuel. There should be no
fuel in the vacuum line.
D An intermittent TP sensor output will cause the system
to go rich due to a false indication of the engine
accelerating.
D Shorted Heated Oxygen Sensor (HO2S) –If the HO2S
is internally shorted, the HO2S voltage displayed on
the Tech 2 will be over 1 volt. Try disconnecting the
affected HO2S with the key "ON," engine "OFF." If the
displayed HO2S voltage changes from over 1000 mV
to around 450 mV, replace the HO2S.
contamination of the HO2S can also cause a high
HO2S voltage to be indicated.
indicated by a powdery deposit on the portion of the
HO2S exposed to
contamination is noticed, replace the affected HO2S.
D Open HO2S Signal Circuit or Faulty HO2S–A poor
connection or open in the HO2S signal circuit can
cause the DTC to set during deceleration fuel mode.
DTC P0132 – HO2S Circuit High Voltage Bank 1 Sensor 1
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 1. Install the Tech 2.
2. Run the engine at operating temperature.
3. Operate the vehicle within parameters specified
under "Conditions for Setting the DTC" included in
Diagnostic Support.
4. Using a Tech 2, monitor Bank 1 HO2S 1 voltage.
Does the Bank 1 HO2S 1 voltage remain above the
specified value?
3 1. Ignition "ON," review and record Tech 2 Failure
Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor "DTC" info for DTC P0132
until the DTC P0132 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P0132 failed this
ignition?
4 1. Ignition "OFF."
2. Disconnect Bank 1 HO2S 1.
3. Ignition "ON."
4. At HO2S Bank 1 Sensor 1 connector (PCM side)
use a DVM to measure voltages at the high and low
signal terminals.
Are the voltages in the specified range?
5 Repair short to voltage in signal circuit.
Is the action complete?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Silicon
This condition is
the exhaust stream.
Action
An HO2S which is faulty and not allowing a full voltage
swing between the rich and lean thresholds can also
cause this condition.
monitoring the HO2S voltage with a Tech 2. If the
HO2S voltage is limited within a range between 300
mV to 600 mV, check the HO2S signal circuit wiring
and associated terminal conditions.
D If none of the above conditions are present, replace the
affected HO2S.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. DTC P0132 failing during "deceleration fuel cutoff
mode" operation may indicate a condition described
in the "Diagnostic Aids" above. If the DTC P0132
test passes while the Failure Records conditions are
being duplicated, an intermittent condition is
indicated.
Reviewing the Failure Records vehicle mileage since the
If
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.
Value(s)
—
952 mV (500
mV in
deceleration
fuel cutoff
mode)
—
3-4 V
—
6E–173
Operate the vehicle by
Yes No
Go to OBD
System
Check
Go to Step 2
Go to Step 4 Go to Step 3
Refer to
Diagnostic
Aids
Go to Step 4
Go to Step 5 Go to Step 6
Verify repair —