Isuzu 2000 Trooper Workshop Manual page 951

6E–82
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
FUEL PUMP — Tech 2 Displays ON or OFF —
Indicates the PCM commanded state of the fuel pump
relay driver circuit.
HO2S BANK 1, SEN. 1
— Tech 2 Range 0-1132 mV —
Represents the fuel control exhaust oxygen sensor
output voltage. Should fluctuate constantly within a range
between 10 mV (lean exhaust) and 1000 mV (rich
exhaust) while operating in closed loop.
HO2S BANK 1, SEN. 2
— Tech 2 Range 0-1000mV —
Monitors the exhaust oxygen sensor output voltage. The
PCM monitors the operating efficiency of catalytic
converter by comparing the output voltages of sensor 1
and sensor 2 in this bank. If the catalytic converter is
operating efficiently, the output voltage of sensor 1 will
give a greater fluctuation than that of sensor 2. If the
PCM detects an abnormal level of voltage fluctuation
from sensor 2, a DTC P0420 will be set, indicating that the
catalytic converter for this bank is no longer operating
efficiently.
HO2S BANK2, SEN. 1 —Tech 2 Range 0-1132 mV—
Represents the fuel control exhaust oxygen sensor
output voltage. Should fluctuate constantly within a range
between 10mV (lean exhaust) and 1000 mV (rich
exhaust) while operating in closed loop.
HO2S BANK 2, SEN. 2—Tech 2 Range 0-1000 mV—
Monitors the exhaust oxygen sensor output voltage. The
PCM monitors the operating efficiency of catalytic
converter by comparing the output voltages of sensor 1
and sensor 2 in this bank. If the catalytic converter is
operating efficiently, the output voltage of sensor 1 will
have a greater fluctuation than that of sensor 2. If the
PCM detects an abnormal level of voltage fluctuation
from sensor 2, a DTC P0430 will be set, indicating that the
catalytic converter for this bank is no longer operating
efficiently.
HO2S BANK 1, SEN. 1—Tech 2 Displays NOT
READY or READY—
Indicates the status of the exhaust oxygen sensor. The
Tech 2 will indicate that the exhaust oxygen sensor is
ready when the PCM detects a fluctuating HO2S voltage
sufficient to allow closed loop operation. This will not
occur unless the exhaust oxygen sensor is warmed up.
HO2S BANK 2, SEN. 1 — Tech 2 Displays NOT
READY or READY —
Indicates the status of the exhaust oxygen sensor. The
Tech 2 will indicate that the exhaust oxygen sensor is
ready when the PCM detects a fluctuating HO2S voltage
sufficient to allow closed loop operation. This will not
occur unless the exhaust oxygen sensor is warmed up.
HO2S WARM UP TIME BANK 1, SEN. 1/BANK 1,
SEN 2/BANK 2 SEN. 1/BANK 2 SEN. 2 — Tech 2
Range 00:00:00-99:99:99 HRS:MIN:SEC —
Indicates warm-up time for each HO2S. The HO2S
warm-up time is used for the HO2S heater test. The PCM
will run the heater test only after a cold start (determined
by engine coolant and intake air temperature at the time
of start-up) and only once during an ignition cycle. When
the engine is started the PCM will monitor the HO2S
voltage. When the HO2S voltage indicates a sufficiently
active sensor, the PCM looks at how much time has
elapsed since start-up. If the PCM determines that tool
much time was required for the HO2S to become active,
a DTC will set. If the engine was warm when started,
HO2S warm-up will the display "00:00:00".
IAT (INTAKE AIR TEMPERATURE) — Tech 2 Range
–40°C to 151°C (–40°F to 304°F) —
The PCM converts the resistance of the intake air
temperature sensor to degrees. Intake air temperature
(IAT) is used by the PCM to adjust fuel delivery and spark
timing according to incoming air density.
IGNITION 1 — Tech 2 Range 0-25.5 Volts —
This represents the system voltage measured by the
PCM at its ignition feed.
INJ. PULSE BANK 1/INJ. PULSE BANK 2 — Tech 2
Range 0-1000 msec. —
Indicates the amount of time the PCM is commanding
each injector "ON" during each engine cycle. A longer
injector pulse width will cause more fuel to be delivered.
Injector pulse width should increase with increased
engine load.
LONG TERM FUEL TRIM BANK 1/BANK 2 —
The long term fuel trim is derived from the short term fuel
trim values and represents a long term correction of fuel
delivery for the bank in question. A value of 0% indicates
that fuel delivery requires no compensation to maintain
the PCM commanded air/fuel ratio. A negative value
significantly below 0% indicates that the fuel system is
rich and fuel delivery is being reduced (decreased injector
pulse width). A positive value significantly greater than
0% indicates that a lean condition exists and the PCM is
compensating by adding fuel (increased injector pulse
width). Because long term fuel trim tends to follow short
term fuel trim, a value in the negative range due to
canister purge at idle should not be considered unusual.
Fuel trim values at maximum authority may indicate an
excessively rich or lean system.
Fuel System STATUS — Tech 2 Displays OPEN or
CLOSED —
"CLOSED" indicates that the PCM is controlling fuel
delivery according to oxygen sensor voltage. In "OPEN"
the PCM ignores the oxygen sensor voltage and bases
the amount of fuel to be delivered on TP sensor, engine
coolant, and MAF sensor inputs only.
MAF — Tech 2 Range 0.0-512 gm/s —
MAF (mass air flow) is the MAF input frequency
converted to grams of air per second. This indicates the
amount of air entering the engine.