check engine OPEL FRONTERA 1998 Workshop Manual

6E–249 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1404 EGR Closed Stuck
D06RW106
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if current pintle zero position is different from
the learned zero position. If the PCM detects a pintle
position signal indicates more than 30 % different
between current zero position and the learned zero
position and more than 5 seconds, and this condition
meet 3 times during trip, then the PCM will set DTC
P1404.
Conditions for Setting the DTC
Ignition voltage is between 11 and 16 volts.
Intake Air temp is more than 3C.
Desire EGR position is 0.
Difference EGR pintle position between current and
the learned zero is more than 30 % last more than 5
seconds, and meet three time to the above condition
during a trip. Then it trigger the PCM lights on.
Action Taken When the DTC Sets
The PCM will illuminate the malfunction indicator lamp
(MIL) after consecutive 2nd 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 Failure
Records data.
Conditions for Clearing the MIL/DTC
DTC P1404 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:
Excessive carbon deposit on EGR valve shaft or/and
foreign material may cause no return to EGR valve
fully seated. Those carbon deposit may occur by
unusual port operation. Remove foreign material
or/and excessive carbon deposit on EGR valve shaft
may make return to EGR valve fully seated.
Poor connection or damaged harness – Inspect the
wiring harness for damage. Same as P1406
description
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.

6E–250
ENGINE DRIVEABILITY AND EMISSIONS
DTC P1404 – EGR Closed Stuck
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 “DTC inf. for DTC P1404
until the DTC P1404 test runs. Note the result.
Does the Tech 2 indicates DTC P1404 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. Remove EGR valve from Engine.
2. Inspect EGR valve whether there is any excessive
carbon deposit on EGR shaft.
3. Inspect any foreign material inside of EGR valve.
Was excessive carbon deposit on EGR valve shaft
or/and foreign material in EGR valve ?
—Go to Step 6Go to Step 7
61. Clean up EGR valve shaft and inside of EGR valve.
2. Remove foreign material from EGR valve.
3. Visually inspect damage of pintle and seat whether
there is bent, leakage may occur.
Was there any severe damage which affects function?
3–6 ohmsGo to Step 8
Verify repair
Go to
Step 7
71. Reconnect.
2. Ignition “OFF”.
3. Install the Tech 2.
4. Run the engine at idle.
5. On the Tech 2, select F3:Misc. Test F5:EGR.
6. Use the “UP” arrow to increase the EGR from 0% to
40%.
Did EGR work properly?
——Go to Step 8
81. Reset the learned zero EGR valve position.
2. Repeat step 7.
Did EGR work properly?
—Verify repairGo to Step 9
9Replace the EGR valve.
Replace the EGR valve. Does DTC P1404 still fail
“specific DTC” test on the Tech 2?
—Go to Step 10Verify repair
10Replace 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–252
ENGINE DRIVEABILITY AND EMISSIONS
passage and on the IAC pintle, and excessive deposits
in the throttle bore and on the throttle plate.
Large vacuum leak – Check for a condition that causes
a large vacuum leak, such as an incorrectly installed or
faulty PCV valve or a disconnected brake booster
hose.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 P1508 – IAC System Low RPM
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. Start the engine.
2. Turn all accessories “OFF”(A/C, rear defroster,
etc).
3. Using a Tech 2, command RPM up to 1500, down to
500, and the up to 1500 while monitoring the
“Engine Speed” on the Tech 2.
NOTE: This Tech 2 command may cause the engine to
“cut out” when RPM goes above 1500. If this occurs,
the “cutting out” will stop when the Tech 2 command for
the test is discontinued, or if the Tech 2 command is
changed to less than 1500 RPM.
Does the “Engine Speed” remain within the specified
value of the “Desired Idle” for each RPM command?
50 RPM
No trouble
found. Go to
Diagnostic
Aids
Go to Step 3
31. Disconnect the IAC.
2. Install IAC Node Light 5-8840-2312-0 or equivalent.
3. With the engine running, command RPM up to
1500, down to 500, and then up to 1500 while
observing the node light.
NOTE: This Tech 2 command may cause the engine to
“cut out” when RPM goes above 1500. If this occurs,
the “cutting out” will stop when the Tech 2 command for
the test is discontinued, or if the Tech 2 command is
changed to less than 1500 RPM.
Does each node light cycle red and green (never
“OFF”)?
—Go to Step 5Go to Step 4
41. Check the following circuits for an open, short to
voltage, short ground, or poor connections at the
PCM:
IAC “A” Low.
IAC “A” High.
IAC “B” Low.
IAC “B” High.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8

6E–253 ENGINE DRIVEABILITY AND EMISSIONS
DTC P1508 – IAC System Low RPM
StepNo Ye s Va l u e ( s ) Action
5Visually/physically inspect for following conditions:
Restricted air intake system. Check for a possible
collapsed air intake duct, restricted air filter
element, or foreign objects blocking the air intake
system.
T h r o t t l e b o d y. C h e c k f o r o b j e c t s b l o c k i n g t h e I A C
passage or throttle bore, excessive deposits in
the IAC passage and on the IAC pintle, and
excessive deposits in the throttle bore and on the
throttle plate.
Do any of the above require a repair?
—
Refer to
appropriate
section for
on-vehicle
service
Go to Step 6
61. Check for a poor connection at the IAC harness
connector.
2. If a problem is found, replace faulty terminals as
necessary.
Was a problem found?
—Verify repairGo to Step 7
7Replace the IAC valve.
Is the action complete?
—Verify repair—
8Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

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.

6E–255 ENGINE DRIVEABILITY AND EMISSIONS
Throttle body – Check for sticking throttle plate. Also
inspect the IAC passage for deposits or objects which
keep the IAC pintle from fully extending.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how oftenthe condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
DTC P1509 – IAC System High RPM
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. Start the engine.
2. Turn all accessories “OFF” (A/C, rear defroster,
etc.).
3. Using a Tech 2, command RPM up to 1500, down to
500, and then up to 1500 while monitoring “Engine
Speed” on the Tech 2.
NOTE: This Tech 2 command may cause the engine to
“cut out” when RPM goes above 1500. If this occurs,
the “cutting out” will stop when the Tech 2 command for
the test is discontinued, or if the Tech 2 command is
changed to less than 1500 RPM.
Does the “Engine Speed” remain within the specified
value of “Desired Idle” for each RPM command?
50 RPM
No trouble
found. Go to
Diagnostic
Aids
Go to Step 3
31. Disconnect the IAC.
2. Install IAC Node Light 5-8840-2312-0 or equivalent.
3. With the engine running, command RPM up to
1500, down to 500, and then up to 1500 while
observing the node light.
NOTE: This Tech 2 command may cause the engine to
“cut out” when RPM goes above 1500. If this occurs,
the “cutting out” will stop when the Tech 2 command for
the test is discontinued, or if the Tech 2 command is
changed to less than 1500 RPM.
Does each node light cycle red and green (never
“OFF”)?
—Go to Step 5Go to Step 4
41. Check the following circuits for an open, short to
voltage, short ground, or poor connections at the
PCM:
IAC “A” Low
IAC “A” High
IAC “B” Low
IAC “B” High
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 8
5Visually/physically inspect for following conditions:
Vacuum leaks.
Throttle plate or throttle shaft for binding.
Accelerator and cruise control cables for being
misadjusted or for binding.
Faulty, missing, or incorrectly installed PCV
valve.
Do any of the above require a repair?
—
Refer to
appropriate
section for
on-vehicle
service
Go to Step 6

6E–256
ENGINE DRIVEABILITY AND EMISSIONS
DTC P1509 – IAC System High RPM
StepNo Ye s Va l u e ( s ) Action
61. Check for a poor connection at the IAC harness
connector.
2. If a problem is found, replace faulty terminals as
necessary.
Was a problem found?
—Verify repairGo to Step 7
7Replace the IAC valve.
Is the action complete?
—Verify repair—
8Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed, Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–257 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1618 Serial Peripheral Interface (SPI) PCM
Interprocessor Communication Error
Circuit Description
The serial peripheral interface (SPI) communication is
used internally by the PCM to send messages between
the engine processor and the automatic transmission
processor. Included in each message sent between the
two-processors is a checksum of the message. Both the
engine processor and automatic transmission processor
will compare this check sum value with the calculated
value. If the checksums don’t match, the processor will
view the new data as being corrupted and ignore the
values. The processor will then use the previous
message. The receiving processor will then send a
message to the sending processor informing it that it’s
last message was corrupted.
Conditions for Setting the DTC
Battery voltage is above 9.0 V for 2 seconds.
The PCM detects an internal program fault (check sum
of data communications error).
Check sum fault present for 3 out 6 seconds.
No TCM resets for 2 seconds.
Action Taken When the DTC Sets
The PCM will flash the “Check Trans” lamp 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.
The automatic transmission will operate in the “safety
mode” to protect the mechanical parts of the
transmission. Shift quality and/or gear changes may
not be normal.
Conditions for Clearing the MIL/DTC
DTC P1618 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
DTC P1618 – Serial Peripheral Interface (SPI) PCM Interprocessor
Communication Error
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
2Is the EEPROM calibration the latest version
available?
—Go to Step 4Go to Step 3
3Reprogram the PCM with the latest available
calibrations.
Does DTC 1618 re-appear when the
OBD System
Check
is repeated?—Go to Step 4
Repair
completed
4Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—

6E–258
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1625 PCM Unexpected Reset
Circuit Description
The powertrain control module (PCM) monitors
unexpected PCM reset. This will not turn on MIL light on,
only records code DTC P1625.
Conditions for Setting the DTC
Clock or COP reset.
Action Taken When the DTC Sets
The PCM will not illuminate the malfunction indicator
lamp (MIL).
The PCM will store conditions which were present
when the DTC was set as Failure Records only. This
information will not be stored as Freeze Frame data.
Conditions for Clearing the MIL/DTC
DTC P1625 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:
P1625 alone stored does not need diagnosis. Clear
DTC code.