Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1250

6E1–76

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

EXHAUST GAS RECIRCULATION

(EGR) DIAGNOSIS

057RX001

An EGR flow check diagnosis of the linear EGR system is
covered by DTC P0401, P0404, and P0405. If EGR
diagnostic trouble code P0401 is 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 diagnostics.

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.

BARO kPa – 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.

CMP ACT. COUNTER – Cam Position Activity

DECEL FUEL MODE – Tech 2 Displays ACTIVE or
INACTIVE
”ACTIVE” displayed indicates that the PCM has detected
conditions appropriate to operate in deceleration fuel
mode. The PCM will command the deceleration fuel
mode when it detects a closed throttle position while the
vehicle is traveling over 20 mph. While in the deceleration
fuel mode, the PCM will decrease the amount of fuel
delivered by entering ”Open Loop” and decreasing the
injector pulse width.

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

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 the 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).

EGR TEST COUNT – Tech 2 Range 0–255
Indicates the number of EGR flow test samples collected
during the current ignition cycle. Under normal operation,
only one sample is allowed during an ignition cycle. If the
PCM battery feed has been disconnected or a DTC
P0401 has been cleared, 10 EGR flow test samples will
be allowed during the ignition cycle. This is to allow repair
verification during a single ignition cycle.

ENGINE LOAD – Tech 2 Range 0%–100%
Engine load is calculated by the PCM from engine speed
and MAP 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.

6E1–77

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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.

EVAP VACUUM SWITCH – Tech 2 Displays PURGE
or NO PURGE
The EVAP purge vacuum switch is a normally closed
switch positioned in the purge line between the canister
and the EVAP purge solenoid. The EVAP purge vacuum
switch will open when vacuum increases to greater than
5 inches of water in the purge line. The EVAP purge
vacuum switch is used by the PCM to monitor EVAP
canister purge solenoid operation and purge system
integrity. The EVAP purge vacuum switch should be
closed to ground with no vacuum present (0% EVAP
purge PWM). With EVAP purge PWM at 25% or greater,
the EVAP purge vacuum switch should be open and
”PURGE” should be indicated.

FUEL PUMP – Tech 2 Displays ON or OFF
Indicates the PCM commanded state of the fuel pump
relay driver circuit.

FUEL TRIM CELL – Tech 2 Range 0–21
The fuel trim cell is dependent upon engine speed and
MAF sensor readings. A plot of RPM vs. MAF is divided
into 22 cells. Fuel trim cell indicates which cell is currently
active.

FUEL TRIM LEARN – Tech 2 Displays NO or YES
When conditions are appropriate for enabling long term
fuel trim corrections, fuel trim learn will display YES. This
indicates that the long term fuel trim is responding to the
short term fuel trim. If the fuel trim learn displays NO, then
long term fuel trim will not respond to changes in short
term fuel trim.

GENERATOR CONTROL – Tech 2 Displays ACTIVE
or INACTIVE.

HO2S BANK 1, SEN. 1 – Tech 2 Range 0–1000 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 0–1000 mV
Represents the 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”. This is used along with HO2S
Bank 1, Sensor 3 to determine the catalytic converter
efficiency in the manual transmission models.

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 sensor is warmed up.

HO2S WARM UP TIME BANK 1, SEN. 1 – 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 too
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 display ”00:00:00.”

IAC POSITION – Tech 2 Range 0–255 Counts
Displays the commanded position of the idle air control
pintle in counts. A larger number of counts means that
more air is being commanded through the idle air
passage. Idle air control should respond fairly quickly to
changes in engine load to maintain desired idle RPM.

IAT (INTAKE AIR TEMPERATURE) – Tech 2 Range
–40

C to 151

C (–40

F to 304

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 – 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
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 the 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.

LOOP 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.

6E1–78

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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 (”Check Engine Lamp”).

MISFIRE CUR. CYL. #1/#2/#3/#4 – Tech 2 Range
0–255 Counts
The misfire current counters increase at a rate according
to the number of 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.

MISFIRE CUR. CYL. #1/#2/#3/#4 – 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 the 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.

RICH/LEAN BANK 1 – Tech 2 Displays RICH or
LEAN
Indicates whether oxygen sensor voltage is above a 600
mV threshold voltage (”RICH”) or below a 3000 mV
threshold voltage (”LEAN”). Should change constantly
while in ”Closed Loop”, indicating that the PCM is
controlling the air/fuel mixture properly.

SHORT TERM FT BANK 1
Short term fuel trim to a bank represents a short term
correction to the bank fuel delivery by the PCM in
response to the amount of time the bank fuel control
oxygen sensor voltage spends above or below the 450
mV threshold. If the oxygen sensor voltage has mainly
remained less than 450 mV, indicating a lean air/fuel
mixture, short term fuel trim will increase into the positive
range above 0% and the PCM will pass fuel. If the oxygen
sensor voltage stays mainly above the threshold, short
term fuel trim will decrease below 0% into the negative
range while the PCM reduces fuel delivery to compensate
for the indicated rich condition. Under certain conditions
such as extended idle and high ambient temperatures,
canister purge may cause short term fuel trim to read in
the negative range during normal operation. Fuel trim
values at maximum authority may indicate an excessively
rich or lean system.

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

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 ECT – Tech 2 Range –40

C to 151

(–40

F to 304

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

TP SENSOR – Tech 2 Range 0.00–5.00 Volts
The voltage being monitored by the PCM on the TP
sensor signal circuit.

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.

6E1–79

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

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, for diagnosis, refer to the Symptoms
section.

Test Conditions

Engine running, lower radiator hose hot, transmission in
park or neutral, ”Closed Loop”, accessories OFF, brake
not applied and air conditioning OFF.

2.2L L–4 Engine

Tech 2

Parameter

Data List

Units

Displayed

Typical Data

Values (IDLE)

Typical Data

Values (2500

RPM)

Refer To

Engine Speed

Engine

RPM

804

2511

General Discription and
Operation

Desired Idle
Speed

Engine

RPM

800

General Discription and and
Operation, Idle Air Control

Engine Coolant
Temperature

Engine

88 (190

86 (187

General Discription and and
Operation, Engin coolant
tempereture sensor

Start Up ECT

Engine

General Discription and and
Operation, Engin coolant
tempereture sensor

Intake Air
Temperature

Engine

General Discription and and
Operation, Intake Air
tempereture sensor

Start Up IAT

Engine

General Discription and and
Operation, Intake Air
tempereture sensor

Manifold
Absolute
Pressure

Engine

kPa

General Discription and
Operation, Manifold
Absolute Pressure Sensor.
DTC
P0106,P0107,P0108,P1106,
P1107

Manifold
Absolute
Pressure

Engine

1.31

1.15

General Discription and
Operation, Manifold
Absolute Pressure Sensor.
DTC
P0106,P0107,P0108,P1106,
P1107

Barometric
Pressure

Engine

kPa

101

101 (depends
on altitude and
barometric)

General Discription and
Opreration

Throttle Position

Engine

General Discription and
Opreration, Throttle Position
Sensor. DTC
P0121,P0122,P0123,P1121,
P1122

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