abs ISUZU TROOPER 1998 Service Repair Manual

6E±4
ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor 6E±337. . . . . . . . . . . . . . . . . . . . . . . . .
Linear Exhaust Gas Recirculation (EGR)
Control 6E±337. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mass Air Flow (MAF) Sensor 6E±337. . . . . . . . . . . .
Manifold Absolute Pressure (MAP) Sensor 6E±338
Powertrain Control Module (PCM) 6E±338. . . . . . .
PCM Function 6E±338. . . . . . . . . . . . . . . . . . . . . . . . .
PCM Components 6E±339. . . . . . . . . . . . . . . . . . . . .
PCM Voltage Description 6E±339. . . . . . . . . . . . . . .
PCM Input/Outputs 6E±339. . . . . . . . . . . . . . . . . . . .
PCM Service Precautions 6E±339. . . . . . . . . . . . . .
Reprogramming The PCM 6E±339. . . . . . . . . . . . . .
Throttle Position (TP) Sensor 6E±339. . . . . . . . . . .
Transmission Fluid Temperature (TFT)
Sensor 6E±340. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmission Range Switch 6E±340. . . . . . . . . . . . .
Vehicle Speed Sensor (VSS) 6E±340. . . . . . . . . . . .
Use of Circuit Testing Tools 6E±340. . . . . . . . . . . . .
Aftermarket Electrical and Vacuum
Equipment 6E±340. . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrostatic Discharge Damage 6E±341. . . . . . . . .
Upshift Lamp 6E±341. . . . . . . . . . . . . . . . . . . . . . . . .
General Description (Air Induction) 6E±341. . . . . . . .
Air Induction System 6E±341. . . . . . . . . . . . . . . . . . .
General Description (Fuel Metering) 6E±341. . . . . . .
Acceleration Mode 6E±341. . . . . . . . . . . . . . . . . . . . .
Accelerator Controls 6E±341. . . . . . . . . . . . . . . . . . .
Battery Voltage Correction Mode 6E±341. . . . . . . .
CMP Signal 6E±341. . . . . . . . . . . . . . . . . . . . . . . . . . .
Clear Flood Mode 6E±342. . . . . . . . . . . . . . . . . . . . .
Deceleration Mode 6E±342. . . . . . . . . . . . . . . . . . . .
Engine Speed/Vehicle Speed/Fuel
Disable Mode 6E±342. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Cutoff Mode 6E±342. . . . . . . . . . . . . . . . . . . . . .
Fuel Injector 6E±342. . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Metering System Components 6E±342. . . . . . Fuel Metering System Purpose 6E±342. . . . . . . . . .
Fuel Pressure Regulator 6E±343. . . . . . . . . . . . . . . .
Fuel Pump Electrical Circuit 6E±343. . . . . . . . . . . . .
Fuel Rail 6E±343. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Idle Air Control (IAC) Valve 6E±343. . . . . . . . . . . . .
Run Mode 6E±344. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Mode 6E±344. . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Body Unit 6E±344. . . . . . . . . . . . . . . . . . . . .
General Description (Electronic Ignition
System) 6E±344. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Camshaft Position (CMP) Sensor 6E±344. . . . . . . .
Crankshaft Position (CKP) Sensor 6E±345. . . . . . .
Electronic Ignition 6E±345. . . . . . . . . . . . . . . . . . . . .
Ignition Coils 6E±345. . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition Control 6E±345. . . . . . . . . . . . . . . . . . . . . . . .
Ignition Control PCM Output 6E±347. . . . . . . . . . . .
Knock Sensor (KS) PCM Input 6E±347. . . . . . . . . .
Powertrain Control Module (PCM) 6E±347. . . . . . .
Spark Plug 6E±347. . . . . . . . . . . . . . . . . . . . . . . . . . . .
A/C Clutch Diagnosis 6E±349. . . . . . . . . . . . . . . . . . . .
A/C Clutch Circuit Operation 6E±349. . . . . . . . . . . .
A/C Clutch Circuit Purpose 6E±349. . . . . . . . . . . . .
A/C Request Signal 6E±349. . . . . . . . . . . . . . . . . . . .
General Description (Exhaust Gas
Recirculation (EGR) System) 6E±349. . . . . . . . . . . . .
EGR Purpose 6E±349. . . . . . . . . . . . . . . . . . . . . . . . .
Linear EGR Valve 6E±349. . . . . . . . . . . . . . . . . . . . .
Linear EGR Control 6E±349. . . . . . . . . . . . . . . . . . . .
Linear EGR Valve Operation and Results
of Incorrect Operation 6E±349. . . . . . . . . . . . . . . . .
EGR Pintle Position Sensor 6E±350. . . . . . . . . . . . .
General Description (Positive Crankcase
Ventilation (PCV) System) 6E±350. . . . . . . . . . . . . . .
Crankcase Ventilation System Purpose 6E±350. . .
Crankcase Ventilation System Operation 6E±350.

6E±17 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinouts
PCM Pinout Table, 32-Way Red Connector ± Row ªAº
TS23344
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
A15 Volt Reference ªAºRED5.0 V5.0 VAppropriate Sensor
A2Knock SensorYEL0.0 V DC
2mV AC0.0 V DC
18mV AC
(at idle)General Description and
Operation, Knock Sensor
A3Not UsedÐÐÐÐ
A4Battery FeedWHTB+B+Chassis Electrical
A5Idle Air Control (IAC) ªAº
HighBLUB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A6IAC ªAº LowBLU/WHTB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A7IAC ªBº LowBLU/BLKB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A8IAC ªBº HighBLU/REDB+/0.8 VB+/0.8 VGeneral Description and
Operation, IAC
A9Automatic Transmission
Fluid (ATF) LampORN/BLUB+B+Automatic Transmission
(4L30E)
A10Winter LampPNK/GRNB+B+Automatic Transmission
(4L30E)
A11Power LampGRY/WHTB+B+Automatic Transmission
(4L30E)
A12Antilock Brake System
(ABS)GRYB+B+Antilock Brake System
A13Malfunction Indicator
(Check Engine or MIL)
LampBLU0.0 VB+Chassis Electrical
A14ªCheck Transmissionº
Lamp Driver (AT)ORN/BLKB+B+Chassis Electrical
Up Shift Lamp Driver (MT)ORN/BLU

6E±27 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way Blue Connector ± Row ªFº
TS23346
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
F1Not UsedÐÐÐÐ
F2Transmission Range
Signal ªCºBLU/BLK0.0 V0.0 VAutomatic Transmission
(4L30E)
F3Transmission Range
Signal ªPºYEL/GRNB+0.0 VAutomatic transmission
(4L30E)
F4Brake SwitchGRN/YEL0.0 V0.0 VAutomatic transmission
(4L30E)
F5Power SwitchPPL/REDB+B+Automatic Transmission
(4L30E)
F6Winter SwitchPPL/GRNB+B+Automatic Transmission
(4L30E)
F7Transmission Fluid
TemperatureRED/BLK0.5-4.9 V
(depends on
temperature)0.5-4.9 V
(depends on
temperature)Automatic Transmission
(4L30E)
F8Manifold Absolute
Pressure (MAP)GRY/BLK3.5-4.9 V
(depends on
altitude and
barometric
pressure)0.6-1.3 VGeneral Description and
Operation, Manifold Absolute
Pressure
F9Not UsedÐÐÐÐ
F10Cruise ControlGRY/BLUB+B+Automatic transmission
(4L30E)
F11Kickdown SwitchLT BLUB+B+Automatic Transmission
(4L30E)
F12DIAGORN/BLUB+B+Ð
F13Injector ªCº Cylinder #3GRNB+B+General Description and
Operation, Fuel Injector
F14Shift ªAº SolenoidBRN/REDB+B+Automatic Transmission
(4L30E)
F15Injector Cylinder #5GRN/BLKB+B+General Description and
Operation, Fuel Injector
F16Ignition Feed (1 of 2 E16)RED/BLUB+B+Ð

6E±29 ENGINE DRIVEABILITY AND EMISSIONS
Engine Component Locator Table
Number
NameLocation
1Linear Exhaust Gas Recirculation (EGR) ValveRear right side of the engine
2Throttle Position (TP) SensorOn the rear of the throttle body
3Intake Air Temperature (IAT) SensorOn the intake air duct near the throttle body
4Check Engine (MIL) LightOn the instrument panel beneath the
tachometer
5Positive Crankcase Ventilation (PCV) ValveOn the left of the cylinder head cover
6Air CleanerLeft front of the engine bay
7Mass Air Flow (MAF) SensorAttached to the air filter box
8Camshaft Position (CMP) SensorOn the rear right side at the left of the cylinder
head cover
9Fuel Pressure RegulatorRear right side of the engine
10Idle Air Control (IAC) ValveOn the left of the throttle body
11Upper Intake ManifoldTop of the engine
12Fuse/Relay BoxAlong the inside of the right fender
13Manifold Absolute Pressure (MAP) SensorBolted to the top of the upper intake manifold
14Throttle BodyBetween the intake air duct and the upper
intake manifold
15Engine Coolant Temperature SensorOn the coolant crossover pipe at the front of
the engine, near the throttle body

6E±31 ENGINE DRIVEABILITY AND EMISSIONS
Engine Component Locator Table
Number
NameLocation
1Linear Exhaust Gas Recirculation (EGR) ValveRear right side of the engine
2Throttle Position (TP) SensorOn the rear of the throttle body
3Intake Air Temperature (IAT) SensorOn the intake air duct near the throttle body
4Check Engine (MIL) LightOn the instrument panel beneath the
tachometer
5Positive Crankcase Ventilation (PCV) ValveOn the left of the cylinder head cover
6Air CleanerLeft front of the engine bay
7Mass Air Flow (MAF) SensorAttached to the air filter box
8Camshaft Position (CMP) SensorOn the rear right side at the left of the cylinder
head cover
9Fuel Pressure RegulatorRear right side of the engine
10Idle Air Control (IAC) ValveOn the left of the throttle body
11Upper Intake ManifoldTop of the engine
12Fuse/Relay BoxAlong the inside of the right fender
13Manifold Absolute Pressure (MAP) SensorBolted to the top of the upper intake manifold
14Throttle BodyBetween the intake air duct and the upper
intake manifold
15Engine Coolant Temperature SensorOn the coolant crossover pipe at the front of
the engine, near the throttle body

6E±39 ENGINE DRIVEABILITY AND EMISSIONS
The data displayed on the other Tech 2 will appear the
same, with some exceptions. Some Tech 2s will only be
able to display certain vehicle parameters as values that
are a coded representation of the true or actual value. For
more information on this system of coding, refer to
Decimal/Binary/Hexadecimal Conversions. On this
vehicle Tech 2 displays the actual values for vehicle
parameters. It will not be necessary to perform any
conversions from coded values to actual values.
On-Board Diagnostic (OBD)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The diagnostic test has passed during the current
ignition cycle.

The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:

The diagnostic test has been completed since the last
ignition cycle.

The fault identified by the diagnostic test is currently
active.

The fault has been active during this ignition cycle.

The operating conditions at the time of the failure.
Remember, a fuel trim DTC may be triggered by a list of
vehicle faults. Make use of all information available (other
DTCs stored, rich or lean condition, etc.) when
diagnosing a fuel trim fault.
Comprehensive Component Monitor
Diagnostic Operation
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable, i.e.
Throttle Position (TP) sensor that indicates high throttle
position at low engine loads or MAP voltage. Input
components may include, but are not limited to the
following sensors:

Vehicle Speed Sensor (VSS)

Crankshaft Position (CKP) sensor

Knock Sensor (KS)

Throttle Position (TP) sensor

Engine Coolant Temperature (ECT) sensor

Camshaft Position (CMP) sensor

Manifold Absolute Pressure (MAP) sensor

Mass Air Flow (MAF) sensorIn addition to the circuit continuity and rationality check,
the ECT sensor is monitored for its ability to achieve a
steady state temperature to enable closed loop fuel
control.
Output Components:
Output components are diagnosed for proper response to
control module commands. Components where
functional monitoring is not feasible will be monitored for
circuit continuity and out-of-range values if applicable.
Output components to be monitored include, but are not
limited to, the following circuits:

Idle Air Control (IAC) Motor

Electronic Transmission controls

A/C relays

Cooling fan relay

VSS output

MIL control

Cruise control inhibit
Refer to PCM and Sensors in General Descriptions.
Passive and Active Diagnostic Tests
A passive test is a diagnostic test which simply monitors a
vehicle system or component. Conversely, an active test,
actually takes some sort of action when performing
diagnostic functions, often in response to a failed passive
test. For example, the EGR diagnostic active test will
force the EGR valve open during closed throttle decel
and/or force the EGR valve closed during a steady state.
Either action should result in a change in manifold
pressure.
Intrusive Diagnostic Tests
This is any on-board test run by the Diagnostic
Management System which may have an effect on
vehicle performance or emission levels.
Warm-Up Cycle
A warm-up cycle means that engine at temperature must
reach a minimum of 70
C (160
F) and rise at least 22
C
(40
F) over the course of a trip.
Freeze Frame
Freeze Frame is an element of the Diagnostic
Management System which stores various vehicle
information at the moment an emissions-related fault is
stored in memory and when the MIL is commanded on.
These data can help to identify the cause of a fault. Refer
to
Storing And Erasing Freeze Fame Data for more
detailed information.
Failure Records
Failure Records data is an enhancement of the OBD
Freeze Frame feature. Failure Records store the same
vehicle information as does Freeze Frame, but it will store
that information for any fault which is stored in on-board
memory, while Freeze Frame stores information only for
emission-related faults that command the MIL on.

6E±60
ENGINE DRIVEABILITY AND EMISSIONS
Electronic Ignition System Diagnosis
If the engine cranks but will not run or immediately stalls,
the Engine Cranks But Will Not Start chart must be used
to determine if the failure is the ignition system or the fuel
system. If DTC P0341, or P0336 is set, the appropriate
diagnostic trouble code chart must be used for diagnosis.
If a misfire is being experienced with no DTC set, refer to
the
Symptoms section for diagnosis.
Fuel Metering System Check
Some failures of the fuel metering system will result in an
ªEngine Cranks But Will Not Runº symptom. If this
condition exists, refer to the
Cranks But Will Not Run
chart. This chart will determine if the problem is caused
by the ignition system, the PCM, or the fuel pump
electrical circuit.
Refer to
Fuel System Electrical Test for the fuel system
wiring schematic.
If there is a fuel delivery problem, refer to
Fuel System
Diagnosis
, which diagnoses the fuel injectors, the fuel
pressure regulator, and the fuel pump. If a malfunction
occurs in the fuel metering system, it usually results in
either a rich HO2S signal or a lean HO2S signal. This
condition is indicated by the HO2S voltage, which causes
the PCM to change the fuel calculation (fuel injector pulse
width) based on the HO2S reading. Changes made to the
fuel calculation will be indicated by a change in the long
term fuel trim values which can be monitored with a Tech
2. Ideal long term fuel trim values are around 0%; for a
lean HO2S signal, the PCM will add fuel, resulting in a fuel
trim value above 0%. Some variations in fuel trim values
are normal because all engines are not exactly the same.
If the fuel trim values are greater than +23%, refer to
DTC
P0131, DTC P0151, DTC P0171, and DTC 1171
for items
which can cause a lean HO2S signal.
Idle Air Control (IAC) Valve
The Tech 2 displays the IAC pintle position in counts. A
count of ª0º indicates the PCM is commanding the IAC
pintle to be driven all the way into a fully-seated position.
This is usually caused by a large vacuum leak.
The higher the number of counts, the more air is being
commanded to bypass the throttle blade. Refer to IAC
System Check in order to diagnose the IAC system.
Refer to
Rough, Unstable, or Incorrect Idle, Stalling in
Symptoms for other possible causes of idle problems.
Fuel System Pressure Test
A fuel system pressure test is part of several of the
diagnostic charts and symptom checks. To perform this
test, refer to
Fuel Systems Diagnosis.
Fuel Injector Coil Test Procedure and
Fuel Injector Balance Test Procedure
T32003
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Relieve the fuel pressure by connecting the
5-8840-0378-0 Fuel Pressure Gauge to the fuel
pressure connection on the fuel rail.
CAUTION: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the fuel
pressure connection. The towel will absorb any fuel
leakage that occurs during the connection of the fuel
pressure gauge. Place the towel in an approved
container when the connection of the fuel pressure
gauge is complete.
Place the fuel pressure gauge bleed hose in an
approved gasoline container.
With the ignition switch ªOFF,º open the valve on the
fuel pressure gauge.
3. Record the lowest voltage displayed by the DVM
after the first second of the test. (During the first
second, voltage displayed by the DVM may be
inaccurate due to the initial current surge.)
Injector Specifications:
Resistance Ohms
Voltage Specification at
10
C-35
C (50
F-95
F)
11.8 ± 12.65.7 ± 6.6

The voltage displayed by the DVM should be within
the specified range.

The voltage displayed by the DVM may increase
throughout the test as the fuel injector windings
warm and the resistance of the fuel injector windings
changes.

6E±63 ENGINE DRIVEABILITY AND EMISSIONS
Injector Coil Test Procedure (Steps 1-6) and Injector Balance Test Procedure
(Steps 7-11)

 
StepNo Ye s Value(s) Action
51. Set injector switch box injector #1.
2. Press the ªPush to Start Testº button on the fuel
injector tester.
3. Observe the voltage reading on the DVM.
IMPORTANT:The voltage reading may rise during the
test.
4. Record the lowest voltage observed after the first
second of the test.
5. Set the injector switch box to the next injector and
repeat steps 2, 3, and 4.
Did any fuel injector have an erratic voltage reading
(large fluctuations in voltage that did not stabilize) or a
voltage reading above the specified value?
9.5 VGo to Step 4Go to Step 6
61. Identify the highest voltage reading recorded (other
than those above 9.5 V).
2. Subtract the voltage reading of each injector from
the highest voltage selected in step 1. Repeat until
you have a subtracted value for each injector.
For any injector, is the subtracted Value in step 2
greater than the specified value?
0.6 VGo to Step 4Go to Step 7
7CAUTION: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the
fuel pressure connection. The towel will absorb
any fuel leakage that occurs during the
connection of the fuel pressure gauge. Place the
towel in an approved container when the
connection of the fuel pressure gauge is
complete.
1. Connect the 5-8840-0378-0 Fuel Pressure Gauge
to the fuel pressure test port.
2. Energize the fuel pump using the scan tool.
3. Place the bleed hose of the fuel pressure gauge into
an approved gasoline container.
4. Bleed the air out of the fuel pressure gauge.
5. With the fuel pump running, observe the reading on
the fuel pressure gauge.
Is the fuel pressure within the specified values?
296-376 kPa
(43-55 psi)
Go to Step 8
Go to Fuel
System
Diagnosis
8Turn the fuel pump ªOFF.º
Does the fuel pressure remain constant?
ÐGo to Step 9
Go to Fuel
System
Diagnosis

6E±65 ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor Diagnosis
The Tech 2 has two data displays available for diagnosing
the knock sensor (KS) system. The two displays are
described as follows:

ªKnock Retardº indicates the number of degrees that
the spark timing is being retarded due to a knock
condition.

ªKS Noise Channelº indicates the current voltage level
being monitored on the noise channel.
DTCs P0325 and P0327 are designed to diagnose the KS
module, the knock sensor, and the related wiring. The
problems encountered with the KS system should set a
DTC. However, if no DTC was set but the KS system is
suspect because of a detonation complaint, refer to
Detonation/Spark Knock in Symptoms.
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.

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 (ETC) sensor

The intake air temperature (IAT) sensor

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

The exhaust gas recirculating (EGR) pintle position
sensor

The throttle position (TP) sensor

The manifold absolute pressure (MAP) sensor
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:

P0108

P0113

P0118

P0123

P0560

P0712

P0406
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:

P0108

P0113

P0118

P0123

P0712

P0406
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:

P0107

P0122
In the 5-volt reference circuit A, between the PCM and the
splice, will cause one or more of the following DTCs to be
set:

P0122
In the 5-volt reference circuit B, between the PCM and the
splice, will cause one or more of the following DTCs to be
set:

P0107
Check for the following conditions:

6E±69 ENGINE DRIVEABILITY AND EMISSIONS
HO2S BANK2, SEN. 1ÐTech 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 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 2
SEN. 1 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 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 the display ª00:00:00º.
IAC POSITION Ð Tech 2 Range 0-255 Counts Ð
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) 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.KS NOISE CHANNEL (Knock Sensor) Ð
Indicates the output from the KS noise channel. There is
always some electrical noise in an engine compartment
and to avoid mistaking this as engine knock, the output
from the knock sensor is compared to the output from the
noise channel. A knock condition is not set unless the
knock sensor output is greater than the noise channel
output.
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.
LOOP 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.
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.