check engine OPEL FRONTERA 1998 Workshop Manual

6E–138
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0406 (Flash DTC 26)
EGR Pressure Sensor High Voltage
060RW134
Action Taken When the DTC Sets
The ECM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.
The ECM will store conditions which were present
w h e n t h e D T C w a s s e t a s F r e e z e F r a m e a n d i n F a i l u r e
Records data.
Conditions for Clearing the MIL/DTC
DTC P0404 can be cleared by using the scan tool
“Clear Info” function or by disconnecting the ECM
battery feed.
Diagnostic Aids
Check for the following conditions:
Poor connection or damaged harness – Inspect the
wiring harness for damage.
DTC P0406 – EGR Pressure Sensor High Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
2Put the engine into an idling status.
Is the EGR pressure sensor voltage value displayed on
the Tech 2 above the specified value?
4 VGo to Step 3Go to Step 4
31. Turn off the ignition switch.
2. Remove the sensor connector connection.
3. Turn on the ignition switch “ON”.
Is the EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?
1 VGo to Step 5Go to Step 6

6E–139 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 – EGR Pressure Sensor High Voltage
StepNo Ye s Va l u e ( s ) Action
4Is the EGR pressure sensor voltage value displayed on
the Tech 2 below the specified value?
1 V
Refer to
Chart P0107
Refer to
Diagnostic
Aids
andSymp
tom
Diagnosis
5Connect the relay and solenoid checker
(5-8840-0386-0) to the battery voltage, then check the
sensor grounding circuit.
Does the checker lamp come on?
—Go to Step 7Go to Step 8
6A voltage short circuit occurs in the MAP signal circuit
or this circuit is shorted with the 5V power circuit.
Repair the harness or Replace the ECM (Refer to the
Data Programming in Case of ECM change).
Is the action complete?
—Verify repair—
7Replace the EGR pressure sensor hose or the EGR
pressure sensor.
Is the action complete?
—Verify repair—
8Repair the harness for open ground circuit.
Is the action complete?
—Verify repair—

6E–140
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0475 (Flash DTC 71)
EXH #1 VSV Circuit
060RW135
Circuit Description
EXH. #1, #2 VSV Circuit receives current through Engine
15A fuse, #1 and #2 being connected in parallel.
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 P0475 can be cleared by using the Tech 2 “Clear
Info” 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.

6E–141 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0475 – EXH #1 VSV Circuit Open/Short
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.” Review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor the “ DTC” info for DTC
P0475.
Does the Tech 2 indicate DTC P0475 failed this
ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Ignition “OFF.”
2. Disconnect the EXH #1 VSV connectors.
3. Check the EXH #1 VSV circuit for a short to ground.
Is the EXH #1 VSV circuit shorted to ground?
—Verify repairGo to Step 4
4Replace the EXH #1 VSV.
Is the action complete?
—Verify repairGo to Step 5
51. Ignition “ON,” engine “OFF.” Review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor the “ DTC” info for DTC
P0475.
Does the Tech 2 indicate DTC P0475 failed this
ignition?
—Go to Step 6—
6Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—

6E–142
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1475 (Flash DTC 71)
EXH #2 VSV Circuit Open/Short
060RW135
Circuit Description
EXH. #1, #2 VSV Circuit receives current through Engine
15A fuse, #1 and #2 being connected in parallel.
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 P1475 can be cleared by using the Tech 2 “Clear
Info” 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.

6E–143 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1475 – EXH #2 VSV Circuit Open/Short
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.” Review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor the “ DTC” info for DTC
P1475.
Does the Tech 2 indicate DTC P1475 failed this
ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Ignition “OFF.”
2. Disconnect the EXH #2 connectors.
3. Check the EXH #2 circuit for a short to ground.
Is the EXH #2 circuit shorted to ground?
—Verify repairGo to Step 4
4Replace the EXH #2 VSV.
Is the action complete?
—Verify repairGo to Step 5
51. Ignition “ON,” engine “OFF.” Review and record
Tech 2 Failure Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor the “ DTC” info for DTC
P1475.
Does the Tech 2 indicate DTC P1475 failed this
ignition?
—Go to Step 6—
6Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—

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 “Clear
Info” 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
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.”
2. With the throttle closed by the hand, observe the
“ITP Sensor” display on the Tech 2.
Is the “ITP Sensor” 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 Va l u e ( s ) Action
31. Ignition “ON,” engine “OFF.”
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 “DTC” info for DTC
P1485.
Does the Tech 2 indicate DTC P1485 failed?
—Go 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?
—Verify repairGo to Step 5
51. Ignition “ON,” engine “OFF.”
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 “Specific DTC” info for
DTC P1485.
Dose the Tech 2 indicate DTC P1485 failed?
—Go to Step 6
Refer to
Diagnostic
Aids
6Replace the intake throttle.
Is the action complete?
—Verify repairGo to Step 7
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—

6E–146
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1486 (Flash DTC 74)
ITP (Intake Throttle Position) Sensor High 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 P1486 can be cleared by using the Tech 2 “Clear
Info” 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
ITP sensor display on the Tech 2 while moving
connectors and wiring harnesses related to the TP
sensor. A change in the display will indicate the
location of the fault.
Faulty TP sensor – With the ignition key “ON,” engine
“OFF,” observe the TP sensor display on the Tech 2
while slowly depressing the accelerator to wide open
throttle.
If DTC P1486 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–147 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1486 – ITP Sensor High Voltage
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.”
2. With the throttle closed by the hand, observe the
“ITP Sensor” display on the Tech 2.
Is the “ITP Sensor” above the specified value?
4.88 VGo to Step 4Go to Step 3
31. Ignition “ON,” engine “OFF.”
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 “DTC” info for DTC P1486.
Does the Tech 2 indicate DTC P1486 failed.
—Go to Step 4
Refer to
Diagnostic
Aids
4Check for poor electrical connections at the ITP sensor
and replace terminals if necessary.
Did any terminals require replacement?
—Verify repairGo to Step 5
51. Ignition “ON,” engine “OFF.”
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 “DTC” info for DTC
P1486.
Dose the Tech 2 indicate DTC P1486 failed.
—Go to Step 6
Refer to
Diagnostic
Aids
6Replace the intake throttle.
Is the action complete?
—Verify repairGo to Step 7
7Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—