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Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1406

6E2–75

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Multiple PCM Information Sensor DTCs Set

(Cont'd)

Step

Yes

Value(s)

Action

Locate and repair the open circuit in the MAP or EGR or
Vapor Pressure sensor supply circuit.

Is the action complete?

—

Verify repair

—

1. Disconnect the MAP, Vapor pressure sensor and

EGR connector.

2. Ignition “ON”.
3. Measure the resistance of the blow areas:

MAP sensor GND circuit.

EGR GND circuit.

Vapor pressure sensor GND circuit.

Does the voltage resistance near the specified value?

—

Go to

Step 11

Go to

Step 10

Locate and repair the short circuit in the MAP or EGR or
Vapor Pressure sensor signal or GND circuit.

Is the action complete?

—

Verify repair

—

Measure the resistance of the blow areas:

Between CKP Sensor supply circuit and PCM
harness connector. (5Volt supply circuit)

Does the voltage resistance near the specified value?

—

Go to

Step 13

Go to

Step 12

Locate and repair the open circuit in the CKP or CMP
sensor supply circuit.

Is the action complete?

—

Verify repair

—

1.  Disconnect the CKP sensor connector.
2.  Ignition “ON”.
3.  Measure the voltage of the blow areas:

CKP sensor GND circuit and shield circuit.

Does the voltage resistance near the specified value?

—

Go to

Step 15

Go to

Step 14

Locate and repair the short circuit in the CKP sensor
signal or GND circuit.

Is the action complete?

—

Verify repair

—

Are more of the following items for DTCs stored? EGR,
Vapor Pressure Sensor, MAP, CKP, TPS, APS

—

Go to

applicable
DTC table

Go to

Step 16

Replace the PCM.

The replacement PCM must be programmed.

Refer to

ON-Vehicle Service in Power Control Module

and Sensors for procedures.

And also refer to latest Service Bulletin. Check to see
if the latest software is released or not. And then Down
Load the LATEST PROGRAMMED SOFTWARE to the
replacement PCM.

Is the action complete?

—

Go to

OBD

System

Check

—

6E2–76

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Exhaust Gas Recirculation (EGR)

Diagnosis

An EGR flow check diagnosis of the linear EGR system is
covered by DTC P0401. Pintle position error diagnosis is
covered by DTC P0402, P0404, P1404, P0405, P0406. If
EGR diagnostic trouble codes P0401 and/or P0402,
P0404, P1404, P0405, P0406 are encountered, refer to
the DTC charts.

Engine Tech 2 Data Definitions and

Ranges

A/C CLUTCH – Tech 2 Displays ON or OFF –
Indicates whether the PCM has commanded the A/C
clutch ON. Used in A/C system diagnostic.

A/C REQUEST — Tech 2 Displays YES or NO —
Indicates the state of the A/C request input circuit from the
HVAC controls. The PCM uses the A/C request signal to
determine whether A/C compressor operation is being
requested.

AIR/FUEL RATIO — Tech 2 Range 0.0-25.5 —
Air/fuel ratio indicates the PCM commanded value. In
closed loop, the air/fuel ratio should normally be
displayed around “14.2-14.7”. A lower air/fuel ratio
indicates a richer commanded mixture, which may be
seen during power enrichment or TWC protection modes.
A higher air/fuel ratio indicates a leaner commanded
mixture. This can be seen during deceleration fuel mode.

AP1 —Tech 2 Range 0%-100% —
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
“13%” at idle and “85-89%” at wide open throttle.

AP2 —Tech 2 Range 0%-100% —
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
“85-89%” at idle and “11-15%” at wide open throttle.

AP3 —Tech 2 Range 0%-100% —
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
“85-89%” at idle and “32-36%” at wide open throttle.

BAROMETRIC PRESSURE — Tech 2 Range 10-105
kPa/0.00-5.00 Volts —
The barometric pressure reading is determined from the
MAP sensor signal monitored during key up and wide
open throttle (WOT) conditions. The barometric pressure
is used to compensate for altitude differences and is
normally displayed around “61-104” depending on
altitude and barometric pressure.

CHECK TRANS LAMP — AUTO TRANSMISSION —
Indicates the need to check for a DTC with the Tech 2
when the lamp is flashing 0.2 seconds ON and 0.2
seconds OFF.

DESIRED EGR POS. — Tech 2 Range 0%-100% —
Represents the EGR pintle position that the PCM is
commanding.

DESIRED IDLE — Tech 2 Range 0-3187 RPM —
The idle speed that the PCM is commanding. The PCM
will compensate for various engine loads based on engine
coolant temperature, to keep the engine at the desired
speed.

ECT — (Engine Coolant Temperature) Tech 2
Range –40

C to 151

C (–40

F to 304

F) —

The engine coolant temperature (ECT) is mounted in the
coolant stream and sends engine temperature
information to the PCM. The PCM applies 5 volts to the
ECT sensor circuit. The sensor is a thermistor which
changes internal resistance as temperature changes.
When the sensor is cold (high resistance), the PCM
monitors a high signal voltage and interprets that as a cold
engine. As the sensor warms (decreasing resistance),
the voltage signal will decrease and the PCM will interpret
the lower voltage as a warm engine.

EGR DUTY CYCLE — Tech 2 Range 0%-100% —
Represents the EGR valve driver PWM signal from the
PCM. A duty cycle of 0% indicates that no EGR flow is
being commanded; a 100% duty cycle indicates
maximum EGR flow commanded.

EGR FEEDBACK — Tech 2 Range 0.00-5.00 Volts —
Indicates the EGR pintle position sensor signal voltage
being monitored by the PCM. A low voltage indicates a
fully extended pintle (closed valve); a voltage near 5 volts
indicates a retracted pintle (open valve).

ENGINE LOAD — Tech 2 Range 0%-100% —
Engine load is calculated by the PCM from engine speed
and MAF sensor readings. Engine load should increase
with an increase in RPM or air flow.

ENGINE RUN TIME — Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec —
Indicates the time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to
00:00:00.

ENGINE SPEED — Range 0-9999 RPM —
Engine speed is computed by the PCM from the 58X
reference input. It should remain close to desired idle
under various engine loads with engine idling.

EVAP PURGE PWM — Tech 2 Range 0%-100% —
Represents the PCM commanded PWM duty cycle of the
EVAP purge solenoid valve. “0%” displayed indicates no
purge; “100%” displayed indicates full purge.

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.

6E2–77

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

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.

MAP
— Tech 2 Range 10-105 kPa (0.00-4.97 Volts) —
The manifold absolute pressure (MAP) sensor measures
the change in the intake manifold pressure from engine
load, EGR flow, and speed changes. As intake manifold
pressure increases, intake vacuum decreases, resulting
in a higher MAP sensor voltage and kPa reading. The
MAP sensor signal is used to monitor intake manifold
pressure changes during the EGR flow test, to update the
BARO reading, and as an enabling factor for several of
the diagnostics.

MIL — Tech 2 Displays ON or OFF —
Indicates the PCM commanded state of the malfunction
indicator lamp.

MISFIRE CUR. CYL. #1 /#2 /#3 /#4 / #5 / #6 — Tech 2
Range 0-255 Counts —
The misfire current counters increase at a rate according
to the number of the possible misfires being detected on
each cylinder. The counters may normally display some
activity, but the activity should be nearly equal for all the
cylinders.

6E2–78

RODEO 6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

MISFIRE CUR. CYL. #1 /#2 /#3 /#4 / #5 / #6 — Tech 2
Range 0-65535 Counts —
The misfire history counters display the relative level of
misfire that has been detected on each cylinder. The
misfire history counters will not update or show any
activity until a misfire DTC (P0300) has become active.

MISFIRE FAILURES SINCE FIRST FAIL — Tech 2
Range 0-65535 Counts —
Indicates the number of 200 crankshaft revolution sample
periods during which the level of misfire was sufficiently
high to report a fail.

MISFIRE PASSES SINCE FIRST FAIL — Tech 2
Range 0-65535 Counts —
Indicates the number of 200 crankshaft revolution sample
periods during which the level of misfire was sufficiently
low to report a pass.

POWER ENRICHMENT — Tech 2 Displays ACTIVE
or INACTIVE —
“ACTIVE” displayed indicates that the PCM has detected
conditions appropriate to operate in power enrichment
mode. The PCM will command power enrichment mode
when a large increase in throttle position and load is
detected. While in power enrichment mode, the PCM will
increase the amount of fuel delivered by entering open
loop and increasing the injector pulse width. This is done
to prevent a possible sag or hesitation from occurring
during acceleration.

SPARK — Tech 2 Range –64

to 64

—

Displays the amount of spark advance being commanded
by the PCM on the IC circuit.

START-UP ECT — Tech 2 Range –40

C to 151

(–40

F to 304

F) —

Indicates the engine coolant temperature at the time that
the vehicle was started. Used by the HO2S diagnostic to
determine if the last start-up was a cold start.

START-UP IAT — Tech 2 Range –40

C to 151

(–40

F to 304

F) —

Indicates the intake air temperature at the time that the
vehicle was started. Used by the HO2S diagnostic to
determine if the last start-up was a cold start.

TOTAL MISFIRE CURRENT COUNT — Tech 2
Range 0-255 —
Indicates the total number of cylinder firing events that
were detected as being misfires during the last 200
crankshaft revolution sample period.

TP — Tech 2 Range 0%-100% —
TP (throttle position) angle is computed by the PCM from
the TP sensor voltage. TP angle should display “3-5%”
at idle and “100%” at wide open throttle.

CATALYST PROTECTION MODE — Tech 2 Displays
YES or NO —
“YES” displayed indicates that the PCM has detected
conditions appropriate to operate in TWC protection
mode. The PCM will decrease the air/fuel ratio to a value
that depends on mass air flow (higher mass air flow =
lower air/fuel ratio).

UPSHIFT LAMP (MANUAL TRANSMISSION)
VEHICLE SPEED — Tech 2 Range 0-255 km/h
(0-155 mph) —
The vehicle speed sensor signal is converted into km/h
and mph for display.

WEAK CYLINDER — Tech 2 Displays Cylinder
Number —
This indicates that the PCM has detected crankshaft
speed variations that indicate 2% or more cylinder firing
events are misfires.

Typical Scan Data Values

Use the Typical Scan Data Values Table only after the
On-Board Diagnostic System Check has been
completed, no DTC(s) were noted, and you have
determined that the on-board diagnostics are functioning
properly. Tech 2 values from a properly-running engine
may be used for comparison with the engine you are
diagnosing. The typical scan data values represent
values that would be seen on a normally-running engine.

NOTE: A Tech 2 that displays faulty data should not be
used, and the problem should be reported to the Tech 2
manufacturer. Use of a faulty Tech 2 can result in
misdiagnosis and unnecessary replacement of parts.

Only the parameters listed below are referred to in this
service manual for use in diagnosis. For further
information on using the Tech 2 to diagnose the PCM and
related sensors, refer to the applicable reference section
listed below. If all values are within the typical range
described below, refer to the

Symptoms section for

diagnosis.

Test Conditions

Engine running, lower radiator hose hot, transmission in
park or neutral, closed loop, accessories off, brake not
applied and air conditioning off.

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