1998 ISUZU TROOPER Pin IAT sensor

6A±48
ENGINE MECHANICAL
Engine Assembly
Removal
035RW027
1. Disconnect battery ground and positive cable.
2. Remove battery.
3. Make alignment mark on the engine hood and hinges
before removal in order to return the hood to original
position exactly.
4. Remove engine hood.
5. Drain radiator coolant.
6. Disconnect accelerator cable and automatic cruise
control cable from throttle valve on common
chamber.
7. Disconnect air duct with air cleaner cover.
8. Remove air cleaner assembly.
9. Disconnect canister vacuum hose.
10. Disconnect vacuum booster hose.
11. Disconnect three engine harness connectors.
12. Disconnect harness connector to transmission (left
front side of engine compartment), disconnect shift
on the fly harness connector from front side of front
axle and remove transmission harness bracket from
engine left side.
13. Disconnect ground cable between engine and frame.
14. Disconnect bonding cable connector on the back of
right dash panel.
15. Disconnect bonding cable terminal on the left bank.
16. Disconnect starter harness connector from starter.
17. Disconnect generator harness connector from
generator.
18. Disconnect coolant reserve tank hose from radiator.
19. Remove radiator upper and lower hoses.
20. Remove upper fan shroud.
21. Remove cooling fan assembly four fixing nuts, then
the cooling fan assembly.
22. Move drive belt tensioner to loose side using wrench
then remove drive belt.23. Remove power steering pump fixing bolts, then
power steering pump. Place the power steering pump
along with piping on the body side.
24. Remove air conditioning compressor fixing bolts from
bracket and place the compressor along with piping
on the body side.
25. Remove O
2 sensor harness connectors from exhaust
front pipe.
26. Remove three exhaust pipe fixing nuts from each
bank.
27. Remove two exhaust pipe fixing nuts from each
exhaust pipe, then move exhaust pipe to rear side of
vehicle.
28. Remove flywheel dust covers.
29. Disconnect two heater hoses from engine.
30. Disconnect fuel hoses from right side of transmission.
CAUTION: Plug fuel pipes on engine side and fuel
hoses from fuel tank.
31. Remove transmission assembly. Refer to
Transmission section in this manual.
32. Support the engine by engine hoist.
33. Remove two left side engine mount fixing bolts from
engine mount on chassis side.
34. Remove two right side engine mount fixing bolts from
engine mount on chassis side.
35. Remove engine assembly.
Installation
CAUTION: W h e n assembling the engine and
transmission, confirm that dowels have been
mounted in the specified positions at the engine
side. Take care that dowel positions are different
between the manual transmission and the automatic
transmission.

6C±3
ENGINE FUEL

Adhere to all Notices and Cautions.
All gasoline engines are designed to use only unleaded
gasoline. Unleaded gasoline must be used for proper
emission control system operation.
Its use will also minimize spark plug fouling and extend
engine oil life. Using leaded gasoline can damage the
emission control system and could result in loss of
emission warranty coverage.
All cars are equipped with an Evaporative Emission
Control System. The purpose of the system is to minimize
the escape of fuel vapors to the atmosphere.
Fuel Metering
The Engine Control Module (ECM) is in complete control
of this fuel delivery system during normal driving
conditions.
The intake manifold function, like that of a diesel, is used
only to let air into the engine. The fuel is injected by
separate injectors that are mounted over the intake
manifold.
The Manifold Absolute Pressure (MAP) sensor measures
the changes in the intake manifold pressure which result
from engine load and speed changes, which the MAP
sensor converts to a voltage output.
This sensor generates the voltage to change
corresponding to the flow of the air drawn into the engine.
The changing voltage is transformed into an electric
signal and provided to the ECM.
With receipt of the signals sent from the MAP sensor,
Intake Air Temperature sensor and others, the ECM
determines an appropriate fuel injection pulse width
feeding such information to the fuel injector valves to
effect an appropriate air/fuel ratio.
The Multiport Fuel Injection system utilizes an injection
system where the injectors turn on at every crankshaft
revolution. The ECM controls the injector on time so that
the correct amount of fuel is metered depending on
driving conditions.
Two interchangeable ªOº rings are used on the injector
that must be replaced when the injectors are removed.
The fuel rail is attached to the top of the intake manifold
and supplies fuel to all the injectors.
Fuel is recirculated through the rail continually while the
engine is running. This removes air and vapors from the
fuel as well as keeping the fuel cool during hot weather
operation.
The fuel pressure control valve that is mounted on the fuel
rail maintains a pressure differential across the injectors
under all operating conditions. It is accomplished by
controlling the amount of fuel that is recirculated back to
the fuel tank based on engine demand.
See Section ªDriveability and Emissionº for more
information and diagnosis.

6E±3 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0351
Ignition 1 Control Circuit 6E±206. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0352
Ignition 2 Control Circuit 6E±209. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0353
Ignition 3 Control Circuit 6E±212. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0354
Ignition 4 Control Circuit 6E±215. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0355
Ignition 5 Control Circuit 6E±218. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0356
Ignition 6 Control Circuit 6E±221. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0402
EGR Pintle Crank Error 6E±224. . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0404
EGR Open Stuck 6E±226. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0405
EGR Low Voltage 6E±228. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0406
EGR High Voltage 6E±231. . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0502
VSS Circuit Low Input 6E±234. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0562
System Voltage Low 6E±237. . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0563
System Voltage High 6E±239. . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0601
PCM Memory 6E±240. . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1154
HO2S Circuit Transition Time Ratio Bank 2
Sensor 1 6E±241. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1171
Fuel System Lean During Acceleration 6E±245. . . .
Diagnostic Trouble Code (DTC) P1380
ABS Rough Road ABS System Fault 6E±248. . . . . .
Diagnostic Trouble Code (DTC) P1404
EGR Closed Stuck 6E±249. . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1508
IAC System Low RPM 6E±251. . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1509
IAC System High RPM 6E±254. . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1618
Serial Peripheral Interface (SPI) PCM
Interprocessor Communication Error 6E±257. . . . . .
Diagnostic Trouble Code (DTC) P1625
PCM Unexpected Reset 6E±258. . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1640
Driver-1-Input High Voltage 6E±259. . . . . . . . . . . . . .
Symptom Diagnosis 6E±262. . . . . . . . . . . . . . . . . . . . .
Default Matrix Table 6E±288. . . . . . . . . . . . . . . . . . . . .
Camshaft Position (CMP) Sensor 6E±291. . . . . . . . . .
Crankshaft Position (CKP) Sensor 6E±292. . . . . . . . .
Engine Coolant Temperature (ECT) Sensor 6E±292.
Heated Oxygen Sensor (HO2S) 6E±293. . . . . . . . . . .
Intake Air Temperature (IAT) Sensor 6E±295. . . . . . .
Knock Sensor (KS) 6E±296. . . . . . . . . . . . . . . . . . . . . . Mass Air Flow (MAF) Sensor 6E±297. . . . . . . . . . . . .
Manifold Absolute Pressure (MAP) Sensor 6E±297.
Malfunction Indicator Lamp (MIL) 6E±298. . . . . . . . . .
Powertrain Control Module (PCM) 6E±298. . . . . . . . .
EEPROM 6E±300. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Steering Pressure (PSP) Switch 6E±300. . . .
Throttle Position (TP) Sensor 6E±301. . . . . . . . . . . . .
Vehicle Speed Sensor (VSS) 6E±302. . . . . . . . . . . . .
Air Cleaner/Air Filter 6E±303. . . . . . . . . . . . . . . . . . . . .
Idle Air Control (IAC) Valve 6E±304. . . . . . . . . . . . . . .
Common Chamber 6E±305. . . . . . . . . . . . . . . . . . . . . .
Accelerator Cable Assembly 6E±305. . . . . . . . . . . . . .
Accelerator Pedal Replacement 6E±308. . . . . . . . . . .
Fuel Filter Cap 6E±310. . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Filter 6E±310. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Gauge Unit 6E±313. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Injectors 6E±314. . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Pressure Regulator 6E±315. . . . . . . . . . . . . . . . .
Fuel Metering System 6E±317. . . . . . . . . . . . . . . . . . . .
Fuel Pump Assembly 6E±318. . . . . . . . . . . . . . . . . . . .
Fuel Pump Relay 6E±319. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Rail Assembly 6E±319. . . . . . . . . . . . . . . . . . . . . .
Fuel Tank 6E±321. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Body (TB) 6E±323. . . . . . . . . . . . . . . . . . . . . . .
Electronic Ignition System 6E±324. . . . . . . . . . . . . . . .
Catalytic Converter 6E±325. . . . . . . . . . . . . . . . . . . . . .
Air Conditioning Relay 6E±325. . . . . . . . . . . . . . . . . . .
EVAP Canister Hoses 6E±326. . . . . . . . . . . . . . . . . . . .
EVAP Canister 6E±326. . . . . . . . . . . . . . . . . . . . . . . . . .
EVAP Canister Purge Solenoid 6E±327. . . . . . . . . . . .
Fuel Tank Vent Valve 6E±328. . . . . . . . . . . . . . . . . . . .
Linear Exhaust Gas Recirculation
(EGR) Valve 6E±328. . . . . . . . . . . . . . . . . . . . . . . . . . .
Positive Crankcase Ventilation (PCV) Valve 6E±329.
Wiring and Connectors 6E±330. . . . . . . . . . . . . . . . . . .
PCM Connectors and Terminals 6E±330. . . . . . . . . . .
Wire Harness Repair: Twisted Shielded
Cable 6E±330. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Twisted Leads 6E±331. . . . . . . . . . . . . . . . . . . . . . . . . .
Weather-Pack Connector 6E±332. . . . . . . . . . . . . . . . .
Com-Pack III 6E±333. . . . . . . . . . . . . . . . . . . . . . . . . . .
Metri-Pack 6E±333. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Description 6E±335. . . . . . . . . . . . . . . . . . . . .
General Description (PCM and Sensors) 6E±335. . .
58X Reference PCM Input 6E±335. . . . . . . . . . . . . .
A/C Request Signal 6E±335. . . . . . . . . . . . . . . . . . . .
Crankshaft Position (CKP) Sensor 6E±335. . . . . . .
Camshaft Position (CMP) Sensor and
Signal 6E±335. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Coolant Temperature (ECT) Sensor 6E±335
Electrically Erasable Programmable Read
Only Memory (EEPROM) 6E±336. . . . . . . . . . . . . .
Fuel Control Heated Oxygen Sensors 6E±336. . . .
Intake Air Temperature (IAT) Sensor 6E±336. . . . .

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±19 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way Red Connector ± Row ªBº
TS23344
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
B15 Volt Reference ªBºRED/YEL5.0 V5.0 VAppropriate Sensor
B2lgnition coilRED/WHT0.0 V0.1 VGeneral Description and
Operation
B3lgnition coilRED/BLK0.0 V0.1 VGeneral Description and
Operation
B4lgnition coilRED/GRN0.0 V0.1 VGeneral Description and
Operation
B5Not UsedÐÐÐÐ
B6Not UsedÐÐÐÐ
B7Exhaust Gas Recirculation
(EGR)YEL/RED0.6 V0.6 VGeneral Description and
Operation, Linear EGR
Control
B8Intake Air Temperature
(IAT) SensorYEL/GRN0.5-4.9 V
(depends on
temperature)0.5-4.9 V
(depends on
temperature)General Description and
Operation, IAT
B9Not UsedÐÐÐÐ
B10Not UsedÐÐÐÐ
B11Power Steering Pressure
(PSP) SwitchGRN/YELB+B+General Description and
Operation, PSP
B12Illuminated SwitchGRNB+B+Chassis Electrical
B13Class 2 DataORN/GRN0.0 V0.0 VDiagnosis, Class 2 Serial
Data
B14A/C ClutchGRN/BLKB+
(A/C OFF)B+
(A/C OFF)General Description and
Operation, A/C Clutch Circuit
Operation
B15ECM to ECU
CommunicationViolet0.0 V0.1 VÐ
B16Not UsedÐÐÐÐ

6E±22
ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way White Connector ± Row ªDº
(For except EXPORT and SOUTH AFRICA)
TS23345
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
D1Injector Cylinder #2GRN/ORNB+B+General Description and
Operation, Fuel Injector
D2Torque Converter Clutch
(TCC)BRN/BLU0.0 V0.0 VOn-Vehicle Service, Torque
Converter Clutch
D3Injector Cylinder #1GRN/WHTB+B+General Description and
Operation, Fuel Injector
D4Serial Data (8192)ORN5.0 V5.0 VChassis Electrical
D5Ignition Control, Cylinder
#5RED/YEL0.0 V0.1 VGeneral Description and
Operation, Ignition Coil
D6Ignition Control, Cylinder
#3RED/BLUE0.0 V0.0 VGeneral Description and
Operation, Ignition Coil
D7VSS Input / IMOB
ResponseWHT/BLK0.0 V0.1 V
(at rest)Chassis Electrical
D8Sensor Ground 5V
Reference A ReturnGRN0.0 V0.0 VAppropriate Sensor
D9Sensor Ground 5 V
Reference B ReturnGRY0.0 V0.0 VAppropriate Sensor
D10Mass Air Flow (MAF)YEL4.9 V4.2 VGeneral Description, Mass
Air Flow Sensor
D11Camshaft Position SensorWHT5.0 V or less
than 1.0 V4.6 VGeneral Description and
Operation, Camshaft
Position Sensor
D12Not UsedÐÐÐÐ
D13Not UsedÐÐÐÐ
D14Bank 1 HO2S 1 LowGRN0.0 V0.1 VGeneral Description and
Operation, Fuel HO2S 1
D15Bank 1 HO2S 1 SignalRED0.4 V0.1-0.9 VGeneral Description and
Operation, Fuel HO2S 1
D16Not UsedÐÐÐÐ

6E±23 ENGINE DRIVEABILITY AND EMISSIONS
PCM Pinout Table, 32-Way White Connector ± Row ªDº
(For EXPORT and SOUTH AFRICA)
TS23345
PINPIN FunctionWire ColorIGN ONENG RUNRefer To
D1Injector Cylinder #2GRN/ORNB+B+General Description and
Operation, Fuel Injector
D2Torque Converter Clutch
(TCC)BRN/BLU0.0 V0.0 VOn-Vehicle Service, Torque
Converter Clutch
D3Injector Cylinder #1GRN/WHTB+B+General Description and
Operation, Fuel Injector
D4Serial Data (8192)ORN5.0 V5.0 VChassis Electrical
D5Ignition Control, Cylinder
#5RED/YEL0.0 V0.1 VGeneral Description and
Operation, Ignition Coil
D6Ignition Control, Cylinder
#3RED/BLUE0.0 V0.0 VGeneral Description and
Operation, Ignition Coil
D7VSS Input / IMOB
ResponseLIGHT
GRN/WHT0.0 V0.1 V
(at rest)Chassis Electrical
D8Sensor Ground 5V
Reference A ReturnGRN0.0 V0.0 VAppropriate Sensor
D9Sensor Ground 5 V
Reference B ReturnGRY0.0 V0.0 VAppropriate Sensor
D10Mass Air Flow (MAF)YEL4.9 V4.2 VGeneral Description, Mass
Air Flow Sensor
D11Camshaft Position SensorWHT5.0 V or less
than 1.0 V4.6 VGeneral Description and
Operation, Camshaft
Position Sensor
D12Not UsedÐÐÐÐ
D13Not UsedÐÐÐÐ
D14Not UsedÐÐÐÐ
D15Not UsedÐÐÐÐ
D16Not UsedÐÐÐÐ

6E±38
ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
OBD Serviceablity Issues
The list of non-vehicle faults that could affect the
performance of the OBD system has been compiled.
These non-vehicle faults vary from environmental
conditions to the quality of fuel used.
The illumination of the MIL (ªCheck Engineº lamp) due to
a non-vehicle fault could lead to misdiagnosis of the
vehicle, increased warranty expense and customer
dissatisfaction. The following list of non-vehicle faults
does not include every possible fault and may not apply
equally to all product lines.
Fuel Quality
Using fuel with the wrong octane rating for your vehicle
may cause driveability problems. Many of the major fuel
companies advertise that using ªpremiumº gasoline will
improve the performance of your vehicle. Most premium
fuels use alcohol to increase the octane rating of the fuel.
Although alcohol-enhanced fuels may raise the octane
rating, the fuel's ability to turn into vapor in cold
temperatures deteriorates. This may affect the starting
ability and cold driveability of the engine.
Low fuel levels can lead to fuel starvation, lean engine
operation, and eventually engine misfire.
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts. Something as simple as a
high-performance exhaust system that affects exhaust
system back pressure could potentially interfere with the
operation of the EGR valve and thereby turn on the MIL
(ªCheck Engineº lamp). Small leaks in the exhaust
system near the post catalyst oxygen sensor can also
cause the MIL (ªCheck Engineº lamp) to turn on.
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL (ªCheck
Engineº lamp).
Environment
Temporary environmental conditions, such as localized
flooding, will have an effect on the vehicle ignition system.
If the ignition system is rain-soaked, it can temporarily
cause engine misfire and turn on the MIL (ªCheck Engineº
lamp).
Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(ªCheck Engineº lamp) to turn on if the vehicle is not
maintained properly. Restricted air filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD. Poor vehicle
maintenance can not be classified as a ªnon-vehicle
faultº, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.Related System Faults
Many of the OBD system diagnostics will not run if the
PCM detects a fault on a related system or component.
One example would be that if the PCM detected a Misfire
fault, the diagnostics on the catalytic converter would be
suspended until Misfire fault was repaired. If the Misfire
fault was severe enough, the catalytic converter could be
damaged due to overheating and would never set a
Catalyst DTC until the Misfire fault was repaired and the
Catalyst diagnostic was allowed to run to completion. If
this happens, the customer may have to make two trips to
the dealership in order to repair the vehicle.
Maintenance Schedule
Refer to the Maintenance Schedule.
Visual / Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:

Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.

Inspect hoses that are difficult to see behind other
components.

Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the ªClass IIº communication system.
Each bit of information can have one of two lengths: long
or short. This allows vehicle wiring to be reduced by
transmitting and receiving multiple signals over a single
wire. The messages carried on Class II data streams are
also prioritized. If two messages attempt to establish
communications on the data line at the same time, only
the message with higher priority will continue. The device
with the lower priority message must wait. The most
significant result of this regulation is that it provides Tech 2
manufacturers with the capability to access data from any
make or model vehicle that is sold.