1998 ISUZU TROOPER DTC 1485

6E±4
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Aids 6E±122. . . . . . . . . . . . . . . . . . . . . . . .
Test Description 6E±122. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0380
(Flash DTC 66) Glow Relay Circuit
Open/Short 6E±126. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±126. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±126. . . . . . .
Conditions for Clearing the MIL/DTC 6E±126. . . . .
Diagnostic Aids 6E±126. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0381
(Flash DTC 67) Glow Lamp Circuit
Open/Short 6E±128. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±128. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±128. . . . . . .
Conditions for Clearing the MIL/DTC 6E±128. . . . .
Diagnostic Aids 6E±128. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1403
(Flash DTC 32) EGR EVRV Fault 6E±130. . . . . . . . .
Circuit Description 6E±130. . . . . . . . . . . . . . . . . . . . .
Diagnostic Aids 6E±130. . . . . . . . . . . . . . . . . . . . . . . .
Test Description 6E±130. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1404
(Flash DTC 31) EGR VSV Circuit 6E±132. . . . . . . . .
Circuit Description 6E±132. . . . . . . . . . . . . . . . . . . . .
Diagnostic Aids 6E±132. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0405
(Flash DTC 26) EGR Pressure Sensor
Low Voltage 6E±134. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±134. . . . . . .
Conditions for Clearing the MIL/DTC 6E±134. . . . .
Diagnostic Aids 6E±134. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1405
(Flash DTC 37) EGR EVRV Circuit
Open/Short 6E±136. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±136. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±136. . . . . . .
Conditions for Clearing the MIL/DTC 6E±136. . . . .
Diagnostic Aids 6E±136. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0406
(Flash DTC 26) EGR Pressure Sensor
High Voltage 6E±138. . . . . . . . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±138. . . . . . .
Conditions for Clearing the MIL/DTC 6E±138. . . . .
Diagnostic Aids 6E±138. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0475
(Flash DTC 71) EXH #1 VSV Circuit 6E±140. . . . . . .
Circuit Description 6E±140. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±140. . . . . . .
Conditions for Clearing the MIL/DTC 6E±140. . . . .
Diagnostic Aids 6E±140. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1475
(Flash DTC 71) EXH #2 VSV Circuit
Open/Short 6E±142. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±142. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±142. . . . . . . Conditions for Clearing the MIL/DTC 6E±142. . . . .
Diagnostic Aids 6E±142. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1485
(Flash DTC 74) ITP (Intake Thorottle Position)
Sensor Low Voltage 6E±144. . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±144. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±144. . . . . . .
Conditions for Clearing the MIL/DTC 6E±144. . . . .
Diagnostic Aids 6E±144. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1486
(Flash DTC 74) ITP (Intake Throttle Position)
Sensor High Voltage 6E±146. . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±146. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±146. . . . . . .
Conditions for Clearing the MIL/DTC 6E±146. . . . .
Diagnostic Aids 6E±146. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1487
(Flash DTC 73) Intake Throttle System
Circuit Open/Start 6E±148. . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±148. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±148. . . . . . .
Conditions for Clearing the MIL/DTC 6E±148. . . . .
Diagnostic Aids 6E±148. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1488
(Flash DTC 72) Intake Throttle Motor Control
Circuit Signal Gap 6E±150. . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±150. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±150. . . . . . .
Conditions for Clearing the MIL/DTC 6E±150. . . . .
Diagnostic Aids 6E±150. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0502
(Flash DTC 24) VSS (Vehicle Speed Sensor)
No Signal 6E±152. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±152. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±152. . . . . . .
Conditions for Clearing the MIL/DTC 6E±152. . . . .
Test Description 6E±153. . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0510
(Flash DTC 75) Idle SW Malfunction, Open
Circuit 6E±155. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±155. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±155. . . . . . .
Conditions for Clearing the MIL/DTC 6E±155. . . . .
Diagnostic Aids 6E±155. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P1510
(Flash DTC 75) Idle SW Malfunction
Short Circuit 6E±157. . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Description 6E±157. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±157. . . . . . .
Conditions for Clearing the MIL/DTC 6E±157. . . . .
Diagnostic Aids 6E±157. . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Trouble Code (DTC) P0562
(Flash DTC 35) System Voltage Too Low 6E±159. .
Circuit Description 6E±159. . . . . . . . . . . . . . . . . . . . .
Action Taken When the DTC Sets 6E±159. . . . . . .

6E±38
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
On- Board Diagnostic (OBD) System Check

StepActionValue(s)Ye sNo
11. Ignition ªON,º engine ªOFF.º
2. Observe the malfunction indicator lamp (MIL or
ªCheck Engineº lamp).
Is the MIL (ªCheck Engineº lamp)ªON?º
ÐGo to Step 2
Go to No MIL
(ªCheck
Engineº lamp)
21. Ignition ªOFF.º
2. Install a Tech 2.
3. Ignition ªON.º
4. Attempt to display ECM engine data with the Tech 2.
Does the Tech 2 display ECM data?
ÐGo to Step 3Go to Step 8
31. Using the Tech 2 output tests function, select MIL
(ªCheck Engineº lamp) dash lamp control and
command the MIL (ªCheck Engineº lamp) ªOFF.º
2. Observe the MIL (ªCheck Engineº lamp).
Did the MIL (ªCheck Engineº lamp) turn ªOFF?º
ÐGo to Step 4
Go to MIL
(ªCheck
Engineº lamp)
On Steady
4Attempt to start the engine.
Did the engine start and continue to run?
ÐGo to Step 5
Go to Cranks
But Will Not
Run
5Select ªDisplay DTCsº with the Tech 2.
Are any DTCs stored?
ÐGo to Step 6Go to Step 7
6Are two or more of the following DTCs stored?
A Group; P0337, P0342, P1193, P1404, P1405,
P1488
B Group; P0337, P0342
C Group; P0112, P0117, P0182, P0197
D Group; P0107, P0405, P1194, P1485
Ð
Go to Chart,
ªMultiple
ECM
Information
Sensor DTCs
Setº
Go to
applicable
DTC table
7Compare ECM 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?
ÐGo to Step 8
Refer to
indicated
Component
System
Checks
81. Ignition ªOFF,º disconnect the ECM.
2. Ignition ªON,º engine ªOFF.º
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 9
9Check the Tech 2 on other vehicle.
Was Tech 2 abnormal?
ÐGo to Step 11Go to Step 10
10Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐGo to Step 2Ð
11Repair the Tech 2 or prepare another Tech 2.
Is the action complete?
ÐGo to Step 2Ð

6E±39 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Engine Control Module ECM
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 ECM memory.
Diagnostic trouble codes can also be cleared by turning
the ignition ªOFFº and disconnecting the battery power
from the ECM for 30 seconds. Turning off the ignition and
disconnecting the battery power from the ECM will cause
all diagnostic information in the ECM memory to be
cleared. Therefore, all the diagnostic tests will have to be
re-run.
Since the ECM 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 ECM connections
or the ECM is the cause of a problem, and the ECM is
replaced, but this does not correct the problem, one of the
following may be the reason:

There is a problem with the ECM 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 components 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 ECM using internal electronic switches called
drivers. A shorted solenoid, relay coil, or harness will
not damage the ECM but will cause the solenoid or
relay to be inoperative.
Multiple ECM Information Sensor
DTCS Set
Circuit Description
The Engine Control Module ECM monitors various
sensors to determine the engine operating conditions.
The ECM controls fuel delivery, spark advance,
transmission operation, and emission control device
operation based on the sensor inputs.
The ECM provides a sensor ground to all of the sensors.
The ECM 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 fuel temperature (FT) sensor

The engine coolant temperature (ECT) sensor

The Intake air temperature (IAT) sensor
The ECM provides the following sensors with a 5-volt
reference and a sensor ground signal:

The Intake throttle position sensor

The manifold absolute pressure sensor

The rail pressure sensor

The accelerator position sensor

The oil temperature sensor
The camshaft position sensor

The crankshaft position sensor

The EGR pressure sensor
The ECM monitors the signals from these sensors in
order to determine their operating status.
Diagnostic Aids
IMPORTANT:Be sure to inspect ECM 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:

P0337

P0342

P1193

P1404

P1405

P1488
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 ECM
and the splice will cause one or more of the following
DTCs to be set:

P0337

P0342

P0117
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:

P0112

P0117

P0182

P0197
An open in the 5-volt reference circuit A, between the
ECM and the splice will cause one or more of the following
DTCs to be set:

P0107

P0405

P1194

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

P1485
Check for the following conditions:

Poor connection at ECM. 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's 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:

ECT Sensor

6E±42
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
4JX1-TC Engine (Automatic and Manual Transmission)
Tech 2
Parameter
Data ListUnits
DisplayedTypical Data
Values (IDLE)Typical Data
Values
(2500 RPM)Refer To
Battery VoltageEngineVolts12.5 ~ 14.513 ~ 15General Description
Ignition StatusEngineOn/OffOnOnGeneral Description
Ignition Relay2EngineOn/OffOnOnGeneral Description
Idle SwitchEngineInactive/
ActiveÐÐDTC P0510, P1510
Manifold
Absolute
PressureEngineKPa96 ~ 106110 ~ 150General Description
DTC P0107, P0108
Rail Oil
PressureEngineMPa3.5 ~ 54.5 ~ 10General Description
DTC P0192, P0193
Desired Rail Oil
PressureEngineMPa4 ~ 55 ~ 9General Description
DTC P0192, P0193
Fuel
TemperatureEngine
C (
F)75 ~ 8575 ~ 85DTC P0182, P0183
Quick Warming
SwitchEngineOn/OffOffOffDTC P0380
Thermo RelayEngineOn/OffÐÐDTC P1655
Actual EGR
PressureEngineKPa58 ~ 60M/T 63 ~ 66
A/T 95 ~ 105DTC P0405, P0406
Barometric
PressureEngineKPa98 ~ 10298 ~ 102General Description
Relative EGR
PressureEngineKPa±38 ~ ±45M/T ±34 ~ ±37
A/T 0General Description
Desired EGR
PressureEngineKPa±43 ~ ±40M/T 36
A/T 0General Description
Brake SwitchEngineInactive/
ActiveÐÐDTC P1588
GearEngineÐÐÐÐ
Vehicle SpeedEngineKm/h00Transmission Diagnosis
Rail Pressure
Control ValveEngine%17 ~ 2218 ~ 27DTC P1193
EGR StatusEngineDisable/
EnableEnableM/T Enable
A/T DisableGeneral Description
EGR Switching
ValveEngineOn/OffÐÐGeneral Description
Throttle Motor
Position SensorEngineVolts3.1 ~ 3.90.2 ~ 0.9DTC P1485, P1486,
P1487
Throttle Motor
PositionEngineSteps
0 ~ 1.00 ~ 1.0
DTC P1488
Delirered Fuel
QuantityEnginemm 3/st
6 ~ 106 ~ 12
General Description
Injector StatusEngineDisable/
EnableEnableEnableDTC P0201, P0202,
P0203, P0204, General
Description
Injector Pulse
WidthEnginems0.9 ~ 1.250.7 ~ 1.1General Description
Injector Start
OffsetEngine
CAÐÐGeneral Description

6E±55 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC
using a
Tech 2Flash DTCDescriptionMIL
P047571EXH #1 VSV Circuit Open/ShortÐ
P147571EXH #2 VSV Circuit Open/ShortÐ
P148574Intake Throttle Position Sensor Low VoltageON
P148674Intake Throttle Position Sensor High VoltageON
P148773Intake Throttle System Circuit Open/ShortON
P148872Intake Throttle Motor Control Circuit Signal GapÐ
P050224Vehicle Speed Sensor No SignalON
P051075Idle SW Malfunction, Open CircuitON
P151075Idle SW Malfunction, Short CircuitON
P056235System Voltage Too LowON
P156235System Voltage Too Low at CrankingON
P158725Brake SW Malfunction [B]Ð
P158825Brake SW Malfunction [A]ON
P060155ECM Checksum ErrorON
P162656Immobilizer No SignalON
P163156Immobilizer Wrong SignalON
P164856No Security Code EnteredON
P164956Immobilizer Function not ProgrammedON
P065077Check Engine Lamp Circuit Open/ShortÐ
P065427Techometer Circuit Open/ShortÐ
P165517Thermo Relay Circuit Open/ShortÐ
P165776ECM Main Relay Circuit Open/ShortÐ
P158947TransMission SW Circuit Open/ShortÐ

6E±144
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1485 (Flash DTC 74)
ITP (Intake Thorottle Position) Sensor Low Voltage
060RW134
Circuit Description
The intake throttle position (ITP) sensor circuit provides a
voltage signal that changes relative to throttle blade
angle.
Action Taken When the DTC Sets

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P1485 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at ECM ± Inspect harness connectors
for backed-out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.

Damaged harness ± Inspect the wiring harness for
damage.
If the harness appears to be OK, observe the
throttle position display on the Tech 2 while
moving connectors and wiring harnesses related
to the ITP sensor. A change in the display will
indicate the location of the fault.
If DTC P1485 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.
DTC P1485 ±ITP Sensor Low Voltage

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªON,º engine ªOFF.º
2. With the throttle closed by the hand, observe the
ªITP Sensorº display on the Tech 2.
Is the ªITP Sensorº below the specified value?
0.22 VGo to Step 4Go to Step 3

6E±145 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1485 ±ITP Sensor Low Voltage

 
StepNo Ye s Value(s) Action
31. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor the ªDTCº info for DTC
P1485.
Does the Tech 2 indicate DTC P1485 failed?
ÐGo to Step 4
Refer to
Diagnostic
Aids
4Check the ITP sensor signal circuit for a poor
connection at the ECM and replace the terminal if
necessary.
Did the terminal require replacement?
ÐVerify repairGo to Step 5
51. Ignition ªON,º engine ªOFF.º
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2 monitor the ªSpecific DTCº info for
DTC P1485.
Dose the Tech 2 indicate DTC P1485 failed?
ÐGo to Step 6
Refer to
Diagnostic
Aids
6Replace the intake throttle.
Is the action complete?
ÐVerify repairGo to Step 7
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
ÐVerify repairÐ