sensor ISUZU AXIOM 2002 Service Repair Manual

6E±60
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
On-Board Diagnostic (OBD II) System Check
060R200048
Circuit Description
The on-board diagnostic system check is the starting
point for any driveability complaint diagnosis. Before
using this procedure, perform a careful visual/physical
check of the PCM and engine grounds for cleanliness and
tightness.
The on-board diagnostic system check is an organized
approach to identifying a problem created by an
electronic engine control system malfunction.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed±through wire insulation or a wire broken inside the
insulation. Check for poor connections or a damaged
harness. Inspect the PCM harness and connector for
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire connection,
and damaged harness.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
1.The MIL (ªCheck Engine lampº) should be ªONº
steady with the ignition ªON º and the engine ªOFFº.
If not, the ªNo MILº chart should be used to isolate
the malfunction.
2.The RPL (ªReduced Power lampº) should be ªONº
steady with the ignition ªON ºand the engine ªOFFº.
If not, the ªNo RPLºchart should be used to isolate
the malfunction.3.Checks the Class 2 data circuit and ensures that the
PCM is able to transmit serial data.
4.This test ensures that the PCM is capable of
controlling the MIL (ªCheck Engine lampº) and the
MIL (ªCheck Engine lampº) driver circuit is not
shorted to ground.
5.This test ensures that the PCM is capable of
controlling the RPL (ªReduced Power lampº) and
the RPL (ªReduced Power lampº) driver circuit is not
shorted to ground.
7.Check the DTCs (System ,Volts Supply circuit).
8.Check the DTCs (PCM{Software} detect Errors).
11.If the engine will not start, the Cranks But Will Not
Run chart should be used to diagnose the condition.
14.A Tech 2 parameter which is not within the typical
range may help to isolate the area which is causing
the problem.
15.This vehicle is equipped with a PCM which utilizes
an electrically erasable programmable read only
memory (EEPROM). When the PCM is replaced,
the new PCM must be programmed. Refer to PCM
Replacement and Programming Procedures in
Powertrain Control Module (PCM) and Sensors
of
this section.
10. If the starter motor will not start, the starter control
system chart should be used to diagnose the
condition.

6E±61
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
On-Board Diagnostic (OBD II) System Check

StepActionValue(s)Ye sNo
11. Ignition ªONº, engine ªOFFº.
2. Observe the malfunction indicator lamp (MIL or
ªCheck Engine lampº).
Is the MIL (ªCheck Engine lampº)ªONº?
ÐGo to Step 2
Go to No
MIL(ªCheck
Engine lampº)
21. Ignition ªONº, engine ªOFFº.
2. Observe the ªReduced Power lampº.
Is the RPL (ªReduced Power lampº) ªONº?
ÐGo to Step 3
Go to No
RPL(ªReduce
d Power
lampº)
31. Ignition ªOFFº.
2. Install Tech 2.
3. Ignition ªONº.
4. Attempt to display PCM engine data with the
Tech 2.
Does the Tech 2 display PCM data?
ÐGo to Step 4Go to Step 12
41. Using the Tech 2 output tests function, select MIL
(ªCheck Engine lampº) control and command the
MIL (ªCheck Engine Lampº) ªOFFº.
2. Observe the MIL (ªCheck Engine lampº).
Did the MIL (ªCheck Engine lampº) turn ªOFFº?
ÐGo to Step 5
Go to
MIL(ªCheck
Engine lampº)
On Steady
51. Using the Tech 2 output tests function, select MIL
(ªCheck Engine lampº) control and command the
RPL (ªReduced Power lampº) ªOFFº.
2. Observe the RPL (ªReduced Power lampº).
Did the MIL (ªReduced Power lampº) turn ªOFFº?
ÐGo to Step 6
Go to
RPL(ªReduce
d Power
lampº) On
Steady
6Select ªDisplay DTCsº with the Tech 2.
Are any DTCs stored?
ÐGo to Step 7Go to Step 11
7Stored DTCs.
P0562, P0563, P0601, P0602, P0604, P0606, P1625,
P1635, P1639, P1640, P1650
Are the applicable DTCs stored?
Ð
Go to
applicable
DTC table
Go to Step 8
8Stored DTCs.
P1514, P1515, P1516, P1523, P1125, P1290, P1295,
P1299
Are the applicable DTCs stored?
Ð
Go to
applicable
DTC table
Go to Step 9
9Stored DTCs.
1. P0425, P0106, P0107, P1107, P0401, P1404,
P0405, P1120, P1221, P1515, P1516, P1275,
P1635, P1271, P1273, P1285, P1272
2. P0336, P0337, P1220, P1515, P1221, P1516,
P1280, P1639, P1271, P1272
Are the applicable DTCs stored?
Ð
Go to
ªMultiple
PCM
Information
sensor DTCs
Setº
Go to Step 10
10Attempt to crank the starter motor
Did the starter motor crank?
ÐGo to Step 10
Go to Starter
control
system
11Attempt to start the engine.
Did the engine start and continue to run?
ÐGo to Step 6
Go to Cranks
But Will Not
Run

6E±62
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
On-Board Diagnostic (OBD II) System Check

 
StepNo Ye s Value(s) Action
12Compare PCM data values displayed on the Tech 2 to
the typical engine scan data values.
Are the displayed values normal or close to the typical
values?
Ð
Go to
Symptom
Refer to
indicated
Component
System
Checks
131. Ignition ªOFFº, disconnect the PCM.
2. Ignition ªONº, engine ªOFFº.
3. Check the Class 2 data circuit for an open, short to
ground, or short to voltage. Also, check the DLC
ignition feed circuit for an open or short to ground
and the DLC ground circuit for an open.
4. If a problem is found, repair as necessary.
Was a problem found?
ÐGo to Step 2Go to Step 14
141. Attempt to reprogram the PCM. Refer to Powertrain
Control Module (PCM) in On-Vehicle Service.
2. Attempt to display PCM data with the Tech 2.
Does the Tech 2 display PCM engine data?
ÐGo to Step 2Go to Step 15
15Replace the PCM.
IMPORTANT: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?
ÐGo to Step 2Ð

6E±66
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
A/C Clutch Control Circuit Diagnosis

 
StepNo Ye s Value(s) Action
21Use an ohmmeter to check continuity between the
pressure switch and the A/C thermostat relay.
Was the circuit open?
ÐGo to Step 22Go to Step 23
22Repair the open circuit between the pressure switch
and the A/C thermostat relay.
Is the action complete?
ÐVerify repairÐ
23Check for damaged pin or terminal at F45 of the PCM.
Was a damaged pin or terminal found?
ÐGo to Step 24Go to Step 25
24Repair the damaged pin or terminal.
Is the action complete?
ÐVerify repairÐ
25Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module 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?
ÐVerify repairÐ
261. Remove the A/C compressor relay.
2. Ignition ªONº.
3. Use a DVM to check voltage at both of the wires at
the A/C compressor relay socket.
Is the voltage equal to the specified value?
B+Go to Step 28Go to Step 27
27Repair the faulty wire between the A/C fuse and the
A/C compressor relay .
Is the action complete?
ÐVerify repairÐ
281. A/C compressor relay removed.
2. Engine idling.
3. A/C ªONº.
4. Blower ªONº.
5. Use a DVM to measure voltage between the wire at
the A/C compressor relay socket and battery+.
Did the DVM indicate the specified value?
B+Go to Step 32Go to Step 29
29Check for an open wire between PCM terminal F4 and
the A/C compressor relay.
Was the wire open?
ÐGo to Step 30Go to Step 31
30Repair the open wire between the PCM and the A/C
compressor relay.
Is the action complete?
ÐVerify repairÐ
31Check for a damaged pin or terminal at F4 of the PCM.
Was a damaged pin or a terminal found?
ÐGo to Step 24Go to Step 25

6E±73
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Powertrain Control Module (PCM)
Diagnosis
To read and clear diagnostic trouble codes, use a Tech 2.
IMPORTANT:Use of a Tech 2 is recommended to clear
diagnostic trouble codes from the PCM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition ªOFFº and disconnecting the battery power
from the PCM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the PCM will cause
all diagnostic information in the PCM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re-run.
Since the PCM can have a failure which may affect only
one circuit, following the diagnostic procedures in this
section will determine which circuit has a problem and
where it is.
If a diagnostic chart indicates that the PCM connections
or the PCM is the cause of a problem, and the PCM is
replaced, but this does not correct the problem, one of the
following may be the reason:

There is a problem with the PCM terminal
connections. The terminals may have to be removed
from the connector in order to check them properly.

EEPROM program is not correct for the application.
Incorrect components or reprogramming the PCM
with the wrong EEPROM program may cause a
malfunction and may or may not set a DTC.

The problem is intermittent. This means that the
problem is not present at the time the system is being
checked. In this case, refer to the
Symptoms portion
of the manual and make a careful physical inspection
of all component and wiring associated with the
affected system.

There is a shorted solenoid, relay coil, or harness.
Solenoids and relays are turned ªONº and ªOFFº by
the PCM using internal electronic switches called
drivers. A shorted solenoid, relay coil, or harness will
not damage the PCM but will cause the solenoid or
relay to be inoperative.
Multiple PCM Information Sensor
DTCs Set
Circuit Description
The powertrain control module (PCM) monitors various
sensors to determine the engine operating conditions.
The PCM controls fuel delivery, spark advance,
transmission operation, and emission control device
operation based on the sensor inputs.
The PCM provides a sensor ground to all of the sensors.
The PCM applies 5 volts through a pull±up resistor, and
determines the status of the following sensors by
monitoring the voltage present between the 5±volt supply
and the resistor:

The engine coolant temperature (ECT) sensor

The intake air temperature (IAT) sensor

The transmission fluid temperature (TFT) sensorThe PCM provides the following sensors with a 5±volt
reference and a sensor ground signal:
1

The exhaust gas recirculating (EGR) pintle position
sensor

The manifold absolute pressure (MAP) sensor

The throttle position (TP) sensor 1

The acceleration position (AP) sensor 1

The acceleration position (AP) sensor 3

The Vapor Pressure Sensor
2

The Crank position (CKP) sensor

The throttle position (TP) sensor 2

The acceleration position (AP) sensor 2
The PCM monitors the separate feedback signals from
these sensors in order to determine their operating
status.
Diagnostic Aids
IMPORTANT:Be sure to inspect PCM and engine
grounds for being secure and clean.
A short to voltage in one of the sensor input circuits may
cause one or more of the following DTCs to be set:

P0425

P0108, P1106

P0406

P1120, P1515, P1221, P1516, P1635

P1275, P1639, P1271, P1273

P1285, P1272, P1273

P0336, P0337

P1220, P1515, P1221, P1515, P1516

P1280, P1271, P1272
IMPORTANT:If a sensor input circuit has been shorted
to voltage, ensure that the sensor is not damaged. A
damaged sensor will continue to indicate a high or low
voltage after the affected circuit has been repaired. If the
sensor has been damaged, replace it.
An open in the sensor ground circuit between the PCM
and the splice will cause one or more of the following
DTCs to be set:

P0425

P0108, P1106

P0406

P1120, P1515, P1221, P1516, P1635

P1275, P1639, P1271, P1273

P1285, P1272, P1273

P0336, P0337

P1220, P1515, P1221, P1515, P1516

P1280, P1271, P1272
A short to ground in the 5±volt reference A or B circuit will
cause one or more of the following DTCs to be set:

P0453

P0106, P0107, P1107

P0401, P1404, P0405

P1120, P1515, P1221, P1516, P1635

6E±74
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

P1275, P1639, P1271, P1273

P1285, P1272, P1273

P0336, P0337

P1220, P1515, P1221, P1515, P1516

P1280, P1271, P1272
Check for the following conditions:

Poor connection at PCM. Inspect the harness
connectors for backed±out terminals, improper
mating, broken locks, improperly formed or damage
terminals, and a poor terminal±to±wire connection.
Damaged harness. Inspect the wiring harness for
damage. If the harness is not damaged, observe an
affected sensor fs displayed value on the Tech 2 with
the ignition ªONº and the engine ªOFFº while you
move the connectors and the wiring harnesses
related to the following sensors:

Vapor Pressure (Fuel Tank Pressure) Sensor

MAP Sensor

EGR

TPS1/TPS2

APS1/APS2/APS3

CKP
Multiple PCM Information Sensor DTCs Set

StepActionValue(s)Ye sNo
1Was the ªOn-Board (OBD) System Checkº performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Turn the ignition ªOFFº, disconnect the PCM.
2. Turn the ignition ªONº, check the 5 volt reference 1
and 2 circuit for the following conditions:

A poor connection at the PCM.

An open between the PCM connector and the
splice.

A short to ground.

A short to voltage.
Is there an open or short?
ÐGo to Step 3Go to Step 4
3Repair the open or short.
Is the action complete?
ÐVerify repairÐ
4Check the sensor ground circuit for the following
conditions:

A poor connection at the PCM or the affected
sensors.

An open between the PCM connector and the
affected sensors.
Is there an open or a poor connection?
ÐGo to Step 5Go to Step 6
5Repair the open or the poor connection.
Is the action complete?
ÐVerify repairÐ
6Following below the DTCs stored:
P1635, P1639
Ð
Go to
applicable
DTC table
Go to Step 7
7 Measure the resistance below the items:

Between EGR sensor supply circuit and Vapor
Pressure Sensor supply circuit.

Between MAP sensor supply circuit and Vapor
Pressure Sensor supply circuit.

Between Vapor Pressure Sensor supply circuit
and PCM harness connector. (5Volt supply
circuit)
Is the resistance near the specified value?
ÐGo to Step 9Go to Step 8

6E±75
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Multiple PCM Information Sensor DTCs Set

 
StepNo Ye s Value(s) Action
8Locate and repair the open circuit in the MAP or EGR or
Vapor Pressure sensor supply circuit.
Is the action complete?
ÐVerify repairÐ
91. Disconnect the MAP, Vapor pressure sensor and
EGR connector.
2. Ignition ªONº.
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?
ÐGo to Step 11Go to Step 10
10Locate and repair the short circuit in the MAP or EGR or
Vapor Pressure sensor signal or GND circuit.
Is the action complete?
ÐVerify repairÐ
11 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?
ÐGo to Step 13Go to Step 12
12Locate and repair the open circuit in the CKP or CMP
sensor supply circuit.
Is the action complete?
ÐVerify repairÐ
131. Disconnect the CKP sensor connector.
2. Ignition ªONº.
3. Measure the voltage of the blow areas:

CKP sensor GND circuit and shield circuit.
Does the voltage resistance near the specified value?
ÐGo to Step 15Go to Step 14
14Locate and repair the short circuit in the CKP sensor
signal or GND circuit.
Is the action complete?
ÐVerify repairÐ
15Are more of the following items for DTCs stored? EGR,
Vapor Pressure Sensor, MAP, CKP, TPS, APS
Ð
Go to
applicable
DTC table
Go to Step 16
16Replace 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?
Ð
Go to OBD
System
Check
Ð

6E±76
6VE1 3.5L 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 Ð Tech 2 Displays YES or NO Ð
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 Ð Tech 2 Range 0.0-25.5 Ð
Air/fuel ratio indicates the PCM commanded value. In
closed loop, the air/fuel ratio should normally be
displayed around ª14.2-14.7º. 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 ÐTech 2 Range 0%-100% Ð
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
ª13%º at idle and ª85-89%º at wide open throttle.
AP2 ÐTech 2 Range 0%-100% Ð
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
ª85-89%º at idle and ª11-15%º at wide open throttle.
AP3 ÐTech 2 Range 0%-100% Ð
AP (accelerator pedal) angle is computed by the PCM
from the AP sensor voltage. AP angle should display
ª85-89%º at idle and ª32-36%º at wide open throttle.
BAROMETRIC PRESSURE Ð Tech 2 Range 10-105
kPa/0.00-5.00 Volts Ð
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 ª61-104º depending on
altitude and barometric pressure.
CHECK TRANS LAMP Ð AUTO TRANSMISSION Ð
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. Ð Tech 2 Range 0%-100% Ð
Represents the EGR pintle position that the PCM is
commanding.
DESIRED IDLE Ð Tech 2 Range 0-3187 RPM Ð
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 Ð (Engine Coolant Temperature) Tech 2
Range ±40
C to 151
C (±40
F to 304
F) Ð
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 Ð Tech 2 Range 0%-100% Ð
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 Ð Tech 2 Range 0.00-5.00 Volts Ð
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 Ð Tech 2 Range 0%-100% Ð
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 Ð Tech 2 Range
00:00:00-99:99:99 Hrs:Min:Sec Ð
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 Ð Range 0-9999 RPM Ð
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 Ð Tech 2 Range 0%-100% Ð
Represents the PCM commanded PWM duty cycle of the
EVAP purge solenoid valve. ª0%º displayed indicates no
purge; ª100%º displayed indicates full purge.
FUEL PUMP Ð Tech 2 Displays ON or OFF Ð
Indicates the PCM commanded state of the fuel pump
relay driver circuit.
HO2S BANK 1, SEN. 1
Ð Tech 2 Range 0-1132 mV Ð
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
Ð Tech 2 Range 0-1000mV Ð
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.

6E±77
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
HO2S BANK2, SEN. 1 ÐTech 2 Range 0-1132 mVÐ
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. 2ÐTech 2 Range 0-1000 mVÐ
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. 1ÐTech 2 Displays NOT
READY or READYÐ
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 Ð Tech 2 Displays NOT
READY or READY Ð
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 Ð Tech 2
Range 00:00:00-99:99:99 HRS:MIN:SEC Ð
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 ª00:00:00º.
IAT (INTAKE AIR TEMPERATURE) Ð Tech 2 Range
±40
C to 151
C (±40
F to 304
F) Ð
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 Ð Tech 2 Range 0-25.5 Volts Ð
This represents the system voltage measured by the
PCM at its ignition feed.INJ. PULSE BANK 1/INJ. PULSE BANK 2 Ð Tech 2
Range 0-1000 msec. Ð
Indicates the amount of time the PCM is commanding
each injector ªONº 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 Ð
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 Ð Tech 2 Displays OPEN or
CLOSED Ð
ªCLOSEDº indicates that the PCM is controlling fuel
delivery according to oxygen sensor voltage. In ªOPENº
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 Ð Tech 2 Range 0.0-512 gm/s Ð
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
Ð Tech 2 Range 10-105 kPa (0.00-4.97 Volts) Ð
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 Ð Tech 2 Displays ON or OFF Ð
Indicates the PCM commanded state of the malfunction
indicator lamp.
MISFIRE CUR. CYL. #1 /#2 /#3 /#4 / #5 / #6 Ð Tech 2
Range 0-255 Counts Ð
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.

6E±78
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
MISFIRE CUR. CYL. #1 /#2 /#3 /#4 / #5 / #6 Ð Tech 2
Range 0-65535 Counts Ð
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 Ð Tech 2
Range 0-65535 Counts Ð
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 Ð Tech 2
Range 0-65535 Counts Ð
Indicates the number of 200 crankshaft revolution sample
periods during which the level of misfire was sufficiently
low to report a pass.
POWER ENRICHMENT Ð Tech 2 Displays ACTIVE
or INACTIVE Ð
ªACTIVEº 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 Ð Tech 2 Range ±64
to 64
Ð
Displays the amount of spark advance being commanded
by the PCM on the IC circuit.
START-UP ECT Ð Tech 2 Range ±40
C to 151
C
(±40
F to 304
F) Ð
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 Ð Tech 2 Range ±40
C to 151
C
(±40
F to 304
F) Ð
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 Ð Tech 2
Range 0-255 Ð
Indicates the total number of cylinder firing events that
were detected as being misfires during the last 200
crankshaft revolution sample period.
TP Ð Tech 2 Range 0%-100% Ð
TP (throttle position) angle is computed by the PCM from
the TP sensor voltage. TP angle should display ª3-5%º
at idle and ª100%º at wide open throttle.
CATALYST PROTECTION MODE Ð Tech 2 Displays
YES or NO Ð
ªYESº 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 Ð Tech 2 Range 0-255 km/h
(0-155 mph) Ð
The vehicle speed sensor signal is converted into km/h
and mph for display.
WEAK CYLINDER Ð Tech 2 Displays Cylinder
Number Ð
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.