Back OPEL FRONTERA 1998 Owners Manual

6E–219 ENGINE DRIVEABILITY AND EMISSIONS
Poor connection at PCM – Inspect the harness
connectors for backed-out terminals, improper mating,
broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connections.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Tech 2 display related to DTC P0355 while moving theconnector and wiring related to the ignition system. A
change in the display will indicate the location of the
fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
DTC P0355 – Ignition 5 Control 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 Record
conditions as noted.
4. Use a Tech 2 to monitor the “Specific DTC”
information for DTC P0355 until the DTC P0355 test
runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0355 failed this ignition
cycle?
—Go to Step 3
Go to
Diagnostic
Aids
3Check for faulty connection at ignition coil.
Was a problem found?
—Verify repairGo to Step 4
4Check for faulty connection at PCM connector.
Was a problem found?
—Verify repairGo to Step 5
51. Ignition “ON,” engine “OFF.”
2. Back probe the ignition control circuit 5 at the PCM
with a DVM positive lead with the negative lead to
ground.
Is the voltage near the specified value?
25-55 mVGo to Step 6Go to Step 9
61. Ignition “ON,” engine running.
2. Back probe the ignition control circuit at the PCM for
the cylinder being tested.
Is the voltage in the specified range, rapidly toggling
back and forth to a reading 20-50 mV higher?
100-180 mVGo to Step 7Go to Step 13
71. Ignition “OFF.”
2. Disconnect the 3-pin and 5-pin connectors at the
ignition coil.
3. Check ignition control circuit 5 voltage at the ignition
coil connector while cranking the engine.
Does the voltage measure between the specified
values?
200-1200 mVGo to Step 8Go to Step 11
8Replace the ignition coil.
Is the action complete?
—Verify repair—
91. Ignition “OFF.”
2. Disconnect the PCM and the ignition coil.
3. Check ignition control circuit 5 for short to ground.
Was a problem found?
—Verify repairGo to Step 10
10Check ignition control circuit 5 for short to voltage.
Was a problem found?
—Verify repairGo to Step 13

6E–222
ENGINE DRIVEABILITY AND EMISSIONS
Poor connection at PCM – Inspect the harness
connectors for backed-out terminals, improper mating,
broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connections.
Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Tech 2 display related to DTC P0356 while moving theconnector and wiring related to the ignition system. A
change in the display will indicate the location of the
fault.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
DTC P0356 – Ignition 6 Control 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 Record
conditions as noted.
4. Use a Tech 2 to monitor the “Specific DTC”
information for DTC P0356 until the DTC P0356 test
runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0356 failed this ignition
cycle?
—Go to Step 3
Go to
Diagnostic
Aids
3Check for faulty connection at ignition coil.
Was a problem found?
—Verify repairGo to Step 4
4Check for faulty connection at PCM connector.
Was a problem found?
—Verify repairGo to Step 5
51. Ignition “ON,” engine “OFF.”
2. Back probe the ignition control circuit 6 at the PCM
with a DVM positive lead with the negative lead to
ground.
Is the voltage near the specified value?
25-55 mVGo to Step 6Go to Step 9
61. Ignition “ON,” engine running.
2. Back probe the ignition control circuit at the PCM for
the cylinder being tested.
Is the voltage in the specified range, rapidly toggling
back and forth to a reading 20-50 mV higher?
100-180 mVGo to Step 7Go to Step 13
71. Ignition “OFF.”
2. Disconnect the 3-pin and 5-pin connectors at the
ignition coil.
3. Check ignition control circuit 6 voltage at the ignition
coil connector while cranking the engine.
Does the voltage measure between the specified
values?
200-1200 mVGo to Step 8Go to Step 11
8Replace the ignition coil.
Is the action complete?
—Verify repair—
91. Ignition “OFF.”
2. Disconnect the PCM and the ignition coil.
3. Check ignition control circuit 6 for short to ground.
Was a problem found?
—Verify repairGo to Step 10
10Check ignition control circuit 6 for short to voltage.
Was a problem found?
—Verify repairGo to Step 13

6E–229 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0405 – EGR Low Volt
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 Tech 2, monitor “DTC” info for DTC P0405
until the DTC P0405 test runs. Note the result.
Does Tech 2 indicates DTC P0405 failed this ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
—Go to Step 4Go to Step 5
4Repair the damaged pin or terminal.
Is the action complete?
—Verify repair—
51. Disconnect the EGR harness connector.
2. Ignition “ON”.
3. At the EGR valve, use a DVM to check the voltage
at the 5 volt reference wire (RED) and ground (B).
Did the DVM indicate the specified value?
4–6 VGo to Step 6Go to Step 7
61. Disconnect the EGR harness connector.
2. Measure resistance between terminal B and D.
Was resistance in range?
5–5.5 KGo to Step 10Go to Step 17
71. Ignition “ON”.
2. At the PCM connector, backprobe with a DVM at the
5 volt reference for the EGR valve.
Did the DVM indicate the specified value?
4–6 VGo to Step 8Go to Step 9
8Repair the open 5 volt reference circuit.
Is the action complete?
—Verify repair—
9Repair the damaged sensor ground wire.
Is the action complete?
—Verify repair—
101. Disconnect the EGR harness
2. Use an ohmmeter to measure between the pintle
position pin and the sensor ground pin on the EGR
valve.
NOTE: J-35616 Connector Test Adapter Kit may be
useful for gaining access to the recessed pins on the
valve.
Was the ohmmeter reading approximately equal to the
specified value?
1 to 1.25 KGo to Step 11Go to Step 17
111. Ignition “ON”.
2. Backprobe with a DVM to measure voltage at EGR
valve pintle position pin and sensor ground pin.
Was voltage in range?
Less than
0.1 V
Go to Step 17Go to Step 12

6E–230
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0405 – EGR Low Volt
StepNo Ye s Va l u e ( s ) Action
121. Ignition “ON”.
2. Backprobe with a DVM to measure voltage at PCM
sensor ground pin and pintle position pin.
Was voltage in range?
Less than
0.1 V
Go to Step 13Go to Step 18
131. Ignition “OFF”.
2. Disconnect the EGR harness.
3. Check short circuit between EGR pintle position
circuit and EGR ground circuit.
Was any short circuit?
—Go to Step 14Go to Step 18
14Locate and repair the short to ground in the pintle
position circuit
Is the action complete?
—Verify repair—
151. Ignition “OFF”.
2. Disconnect the PCM.
3. Ignition “ON”.
4. Measure the voltage between the EGR pintle
position circuit and ground.
Is the measured voltage near the specified value?
Less than
0.1 V
Go to Step 17Go to Step 16
16Check for a short circuit between other wires and the
pintle position circuit
Was any short circuit?
—
Repair short
circuit
Verify repair
Go to Step 17
17Replace the EGR valve.
Does DTC P1404 still fail “specific DTC test on Tech 2?
—Go to Step 18Verify repair
18Examine the PCM pin and terminal connection.
Was there a damaged terminal?
—Go to Step 4Go to Step 19
19Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–232
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 – EGR 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”, review and record
Tech 2 Failure Records Data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using Tech 2, monitor “DTC” info for DTC P0406
until the DTC P0406 test runs. Note the result.
Does Tech 2 indicates DTC P0406 failed this ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Disconnect the EGR valve harness connector.
2. Inspect the EGR valve and connectors for damaged
pin or terminals.
Were there any damaged pins or terminals?
—Go to Step 4Go to Step 5
4Repair the damaged pin or terminal.
Is the action complete?
—Verify repair
Is the action
complete?
51. Disconnect the EGR harness connector.
2. Ignition “ON”.
3. At the EGR valve, use a DVM to check the voltage
at the 5 volt reference wire (RED).
Did the DVM indicate the specified value?
4–6 VGo to Step 8Go to Step 6
61. Ignition “ON”.
2. At the PCM connector, backprobe with a DVM at the
5 volt reference for the EGR valve.
Did the DVM indicate the specified value?
4–6 VGo to Step 7Go to Step 16
7Repair the open 5 volt reference circuit
Is the action complete?
—Verify repair—
81. Ignition “OFF”
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between D (5
V reference) and B (Sensor Ground) at EGR sensor
terminals.
NOTE: J-35616 Connector Test Adapter Kit may be
useful for gaining access to the recessed pins on the
valve.
Was there measured resistance in range?
5 to 5 KGo to Step 9Go to Step 15
91. Ignition “OFF”.
2. Disconnect the EGR harness.
3. Use a DVM to check for an resistance between B
and C at EGR sensor terminal.
Was there open circuit?
—Go to Step 15Go to Step 10
101. Ignition “OFF”.
2. Disconnect the EGR harness at PCM connector.
3. Use a DVM to check for shorted wire between A1
and B7.
Was there shorted wire?
—Go to Step 14Go to Step 11

6E–233 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0406 – EGR High Voltage
StepNo Ye s Va l u e ( s ) Action
111. Ignition “ON”.
2. Use a DVM to backprobe at terminal C of EGR
valve for voltage.
Was measured voltage more than 4.8 V?
more than
4.8 V
Go to Step 12Go to Step 12
121. Ignition “ON”.
2. Stay the EGR harness connected.
3. Check voltage by backproving at PCM B7 terminal.
Was voltage more than 4.8 V?
4.8 VGo to Step 16Go to Step 13
131. Locate short circuit at EGR harness between RED
to RED or GREEN, RED to YEL.
2. Replace EGR harness.
Is the action complete?
—Verify repair—
14Replace EGR harness.
Is the action complete?
—Verify repair—
15Replace the EGR valve.
Does DTC P1404 still fail “specific DTC test on Tech 2?
—Go to Step 16Verify repair
16Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–234
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0502 VSS Circuit Low Input
D06RW019
Circuit Description
The vehicle speed sensor has a magnet rotated by the
transmission output shaft. Attached to the sensor is a hall
effect circuit the interacts with the magnetic field treated
by the rotating magnet. A 12-volt operating supply for the
speed sensor hall circuit is supplied from the meter fuse.
The VSS pulses to ground the 9-volt signal sent from the
powertrain control module (PCM) on the reference circuit.
The PCM interprets vehicle speed by the number of
pulses to ground per second on the reference circuit.
Conditions for Setting the DTC
Engine is running.
Engine coolant temperature is above 60C (140F).
Engine speed is between 1800 RPM and 2500 RPM.
Throttle angle is between 10% and 40%.
Engine load is greater than 50 kPa.
MAP sensor indicates greater than 50 kPa manifold
pressure.
PCM detects no VSS signal for 12.5 seconds over a
period of 25 seconds.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.
The PCM 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 P0502 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
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
connects to the engine harness. Power and ground
are applied by jumpers to the VSS through the
connectors which are located just in front of the air
cleaner assembly. The VSS signal is monitored
with a DVM as the rear driveshaft turns. The
wheels can be turned to rotate the driveshaft, or in
2-wheels-drive vehicles the driveshaft can be turned
directly.
12. The speedometer-to-PCM VSS signal wire is
spliced to a wire leading to the cruise control
module. If a short to ground or voltage is indicated
between the PCM and speedometer, it could be on
the cruise control circuit if the vehicle is equipped
with cruise control.

6E–236
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0502 – VSS Circuit Low Input
StepNo Ye s Va l u e ( s ) Action
101. Ignition “OFF.”
2. Disconnect the MAF sensor and remove the air
cleaner assembly and filter element to gain access
to the 16-way black connector located immediately
to the rear of the left front headlamp. The connector
attaches the VSS wires from the transmission
harness to the left-side engine harness.
3. Disconnect the black 16-way connector.
4. Select a terminal adapter from kit J 35616 that can
be used with a jumper to supply B+ to the blue wire
with a yellow tracer (transmission side of the
connector).
5. Use another terminal adapter to attach a voltmeter
to the light-green wire with a w h i l e t r a c e r ( n e x t t o t h e
wire in the previous step.)
6. Disconnect the blue connector next to the black
16-way connector, and locate the black/red tracer
wire at one corner of the blue connector. The
black/red wire is the VSS ground. Use a terminal
adapter to attach a jumper to ground to the
black/red VSS ground wire at the transmission side
of the blue connector.
7. Raise the rear wheels off the ground with
transmission in neutral.
Does the DVM toggle back and forth between 0.6 V and
10 V as the wheels (and driveshaft) are rotated?
—Go to Step 11Go to Step 12
11Replace the VSS.
Is the action complete?
—Verify repair—
12Check for an open or short between the PCM and the
speedometer.
Was a problem found?
—Verify repairGo to Step 13
13Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–251 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1508 IAC System Low RPM
T321115
Circuit Description
The powertrain control module (PCM) controls engine
idle speed by adjusting the position of the idle air control
(IAC) motor pintle. The IAC is a bi-directional stepper
motor driven by two coils. The PCM applies current to the
IAC coils in steps (counts) to extend the IAC pintle into a
passage in the throttle body to decrease air flow. The
PCM reverses the current to retract the pintle, increasing
air flow. This method allows highly accurate control of idle
speed and quick response to changes in engine load. If
the PCM detects a condition where too low of an idle
speed is present and the PCM is unable to adjust idle
speed by increasing the IAC counts, DTC P1508 will set,
indicating a problem with the idle control system.
Conditions for Setting the DTC
No Tech 2 test is being run.
None of these DTCs are set: TP sensor, VSS, ECT,
EGR, fuel system, MAF, MAP, IAT, canister purge,
injector control or ignition control.
Barometric pressure is above 75 kPa.
Engine coolant temperature (ECT) is above 50C
(120
F).
Engine speed is more than 100-200 RPM lower than
desired idle, based upon coolant temperature.
The engine has been running for at least 125 seconds.
Vehicle speed is less than 1 mph.
Canister purge duty cycle is above 10%.
Ignition voltage is between 9.5 volts and 16.7 volts.
The throttle is closed.
Engine speed is lower than desired idle.
All of the above conditions are met for 10 seconds.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
The PCM 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 P1508 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM or IAC motor – 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 for damage.
Restricted air intake system – Check for a possible
collapsed air intake duct, restricted air filter element,
or foreign objects blocking the air intake system.
Throttle body – Check for objects blocking the IAC
passage or throttle bore, excessive deposits in the IAC

6E–254
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1509 IAC System High RPM
T321115
Circuit Description
The powertrain control module (PCM) controls engine
idle speed by adjusting the position of the idle air control
(IAC) motor pintle. The IAC is a bi-directional stepper
motor driven by two coils. The PCM applies current to the
IAC coils in steps (counts) to extend the IAC pintle into a
passage in the throttle body to decrease air flow. The
PCM reverses the current to retract the pintle, increasing
air flow. This method allows highly accurate control of idle
speed and quick response to changes in engine load. If
the PCM detect a condition where too high of an idle
speed is present and the PCM is unable to adjust idle
speed by increasing the IAC counts, DTC P1509 will set,
indicating a problem with the idle control system.
Conditions for Setting the DTC
No Tech 2 test is being run.
None of these DTCs are set: TP sensor, VSS, ECT,
EGR, fuel system, MAF, MAP, IAT, canister purge,
injector control or ignition control.
Barometric pressure is above 75 kPa.
Engine coolant temperature is above 50C (120F).
Engine speed is more than 100-200 RPM lower than
desired idle, based upon coolant temperature.
The engine has been running for at least 125 seconds.
Vehicle speed is less than 1 mph.
Canister purge duty cycle is above 10%.
Ignition voltage is between 9.5 volts and 16.7 volts.
Engine speed is lower than desired idle.
All of the above conditions are met for 5 seconds.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.
The PCM 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 P1509 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:
Poor connection at PCM or IAC motor – 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 for damage.
Vacuum leak – Check for a condition that causes a
vacuum leak, such as disconnected or damaged
h o s e s , l e a k s a t t h e E G R v a l v e a n d t h e E G R p i p e t o t h e
intake manifold, leaks at the throttle body, faulty or
incorrectly installed PCV valve, leaks at the intake
manifold, etc.