check engine OPEL FRONTERA 1998 Workshop Manual

6E–148
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1487 (Flash DTC 73)
Intake Throttle System Circuit Open/Start
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 P1487 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 P1487 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–149 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1487 – Intake Throttle System 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.”
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
P1487.
Does the Tech 2 indicate DTC P1487 failed?
—Go to Step 3
Refer to
Diagnostic
Aids
3Check the ITP circuit for a poor connection at the ECM
and ITP and replace the terminal if necessary.
Did the terminal require replacement?
—Verify repairGo to Step 4
41. Ignition “ON,” engine “OFF.”
2. Operate the throttle by the hand.
Is the action complete?
—Verify repairGo to Step 5
5Replace the ITP Assembly.
Is the action complete?
—Verify repairGo to Step 6
6Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—

6E–150
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1488 (Flash DTC 72)
Intake Throttle Motor Control Circuit Signal Gap
060RW135
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 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 P1488 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 P1488 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–151 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1488 – Intake Throttle Motor Control Circuit Signal Gap
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, 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
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 “Specific DTC” info for
DTC P1488.
Does the Tech 2 indicate DTC P1488 failed?
—Go to Step 4
Refer to
Diagnostic
Aids
4Check the ITP circuit for a poor connection at the ECM
and replace the terminal if necessary.
Did the terminal require replacement?
—Verify repairGo to Step 5
5Check the Intake throttle motor circuit for a poor
connection and replace the terminal if necessary.
Did the terminal require replacement?
—Verify repairGo to Step 6
6Check the ITP Assembly for a poor connection at the
TP sensor and fasten the ITP Assembly if necessary.
Did the ITP Assembly require repair?
—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–153 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
10. To avoid backprobing the VSS and possibly
damaging a seal or terminal, the VSS output can be
tested at the point where the transmission harness
connected to the engine harness. The green 16-way
connector is adjacent to a blue 16-way connector,
and it can be easily accessed by removing the air
cleaner assembly. The green 16-way connector is
separated, and battery voltage is applied to the VSS
through the yellow wire at one corner of the
connector. The VSS output can be monitored with a
DVM connected to the blue wire with a black tracer.
The two wires are next to each other in the 16-way
connector . The test connections are made on the
transmission side of the connector, the side that is
not clipped to the body sheetmetal.11. The speedometer-to-ECM VSS signal wire is
spliced to a wire leading to the cruise control
module. If a short to ground or voltage is found
between the ECM and speedometer, it could be
located between the splice and the cruise control
module.
DTC P0502 –VSS No Signal
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
2Does the speedometer work?—Go to Step 10Go to Step 3
31. Disconnect the VSS connector.
2. Ignition “ON.”
3. Using a test light to battery +, probe the connector
ground wire.
Did the light illuminate?
—Go to Step 5Go to Step 4
4Repair the sensor ground.
Is the action complete?
—Verify repair—
51. Ignition “ON,” sensor disconnected.
2. Using a DVM, measure at the VSS connector
between ground and voltage supply.
Was the measurement near the specified value?
Battery
voltage
Go to Step 7Go to Step 6
6Repair the open or short to ground which may have
blown the meter fuse.
Is the action complete?
—Verify repair—
71. Ignition “ON,” VSS disconnected.
2. Using a DVM, measure at the VSS connector
between ground and the blue/black wire from the
speedometer.
Was the measurement near the specified value?
7.5-8 VGo to Step 9Go to Step 8
8Check for an open or short circuit between the
speedometer and the VSS.
Was an open or short circuit located?
—Verify repairGo to Step 9
9Replace the VSS.
Is the action complete?
—Verify repairGo to Step 10
10Replace the speedometer.
Is the action complete?
—Verify repairGo to Step 11

6E–154
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0502 –VSS No Signal
StepNo Ye s Va l u e ( s ) Action
11Check for an open or short between the ECM and the
speedometer.
Was a problem found?
—Verify repairGo to Step 12
12Replace the ECM (Refer to the Data Programming in
Case of ECM change).
Is the action complete?
—Verify repair—

6E–155 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0510 (Flash DTC 75)
Idle SW Malfunction, Open Circuit
060RW134
Circuit Description
The idle switch signal is used by the Engine Control
Module ECM for fuel control.
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 P0510 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
Idle SW display on the Tech 2 while moving connectors
and wiring harnesses related to the Idle SW.
If DTC P0510 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–156
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P0510 – Idle SW Malfunction, Open Circuit
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. 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
P0510.
Does the Tech 2 indicate DTC P0510 failed?
—Go to Step 4
Refer to
Diagnostic
Aids
3Check the Idle SW circuit for a poor connection and
repair the terminal if necessary.
Did the terminal require repair?
—Verify repairGo to Step 4
41. Ignition “ON.”
2. Operate the accel pedal, and check the data list “ON
OFF” on the Tech 2.
Is the data list correct?
—Verify repairGo to Step 5
5Replace the Idle SW.
Is the action complete?
—Verify repair—

6E–157 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1510 (Flash DTC 75)
Idle SW Malfunction Short Circuit
060RW134
Circuit Description
The idle switch signal is used by the Engine Control
Module ECM for fuel control.
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 P1510 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
Idle SW display on the Tech 2 while moving connectors
and wiring harnesses related to the Idle SW.
If DTC P0122 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–158
4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
DTC P1510 – Idle SW Malfunction, Short Circuit
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. 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
P1510.
Does the Tech 2 indicate DTC P1510 failed?
—Go to Step 4
Refer to
Diagnostic
Aids
3Check the Idle SW circuit for a poor connection and
repair the terminal if necessary.
Did the terminal require repair?
—Verify repairGo to Step 4
41. Ignition “ON.”
2. Operate the accel pedal, and check the data list “ON
OFF” on the Tech 2.
Is the data list correct?
—Verify repairGo to Step 5
5Replace the Idle SW.
Is the action complete?
—Verify repair—