motor OPEL FRONTERA 1998 Owner's Guide
Page 1228 of 6000
6E–111 ENGINE DRIVEABILITY AND EMISSIONS
DTC P0103 – MAF Sensor Circuit High Frequency
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 “DTC” info for DTC P0103.
Does  the  Tech  2  indicate  DTC  P0103  failed  this
ignition?
—Go to Step 3
Refer to
Diagnostic
Aids
31. Start the engine.
2. With  the  engine  idling,  monitor  “MAF  Frequency”
display on the Tech 2.
Is “MAF Frequency” above the specified value?
219 g/SecGo to Step 4Go to Step 7
41. Ignition “OFF.”
2. Disconnect the MAF sensor connector.
3. Ignition “ON,” engine idling.
4. Using a Tech 2, monitor “MAF Frequency.”
Does  the  Tech  2  indicate  a  “MAF  Frequency”  at  the
specified value?
0.0 g/SecGo to Step 5Go to Step 6
5Replace the MAF sensor.
Is the action complete?
—Verify repairGo to Step 8
61. Check the MAF harness for incorrect routing near
high  voltage  components  (solenoids,  relays,
motors).
2. If  incorrect  routing  is  found,    correct  the  harness
routing.
Was a problem found?
—Verify repairGo to Step 7
71. With  the  engine  idling,  monitor  “MAF  Frequency”
display on the Tech 2.
2. Quickly  snap  open  throttle  to  wide  open  throttle
while under a road load and record value.
Does the Tech 2 indicate “MAF Frequency” above the
specified value?
219 g/SecGo to Step 5Go to Step 8
8Replace the PCM.
IMPORTANT:The  replacement  PCM  must  be
programmed.  Refer to 
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair— 
Page 1368 of 6000
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 
Page 1371 of 6000
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. 
Page 1391 of 6000
6E–274
ENGINE DRIVEABILITY AND EMISSIONS
Rough, Unstable, or Incorrect Idle, Stalling Symptom
StepNo Ye s Va l u e ( s ) Action
171. Check ignition coils for cracks or carbon tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 18
18Using Tech 2, monitor the throttle position (TP) angle
with the engine idling.
Is the TP angle at the specified value and steady?
0%Go to Step 19
Refer to DTC
P0123
 for
further
diagnosis
191. Check  the  positive  crankcase  ventilation  (PCV)
valve  for  proper  operation.    Refer  to 
Crankcase
Ventilation System
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 20
201. Check  the  transmission  range  switch  circuit.    Use
Tech 2 and be sure Tech 2 indicates that the vehicle
is in drive with the gear selector in drive or overdrive.
2. If  a  problem  is  found,  diagnose  and  repair  the
transmission  range  switch  as  necessary  (refer  to
4L30-E Automatic Transmission Diagnosis).
Was a problem found?
—Verify repairGo to Step 21
211. Check for the following engine mechanical items.
Refer  to 
Engine  Mechanical  for  diagnosis
procedures:
EGR valve mounted backward.  Compare with
a known-good vehicle.
Low compression
Sticking or leaking valves
Worn camshaft lobe(s)
Camshaft drive belt slipped or stripped
Incorrect valve timing
Worn rocker arms
Broken valve springs
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 22
221. Check  for  faulty  motor  mounts.    Refer  to Engine
Mechanical
 for inspection of mounts.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 23
231. Review all diagnostic procedures within this table.
2. If  all  procedures  have  been  completed  and  no
malfunctions  have  been  found,  review/inspect  the
following:
Visual/physical inspection
Te c h   2   d a t a
Freeze Frame data/Failure Records buffer
All  electrical  connections  within  a  suspected
circuit and/or system.
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance 
Page 1401 of 6000
6E–284
ENGINE DRIVEABILITY AND EMISSIONS
Cuts Out, Misses Symptom
StepNo Ye s Va l u e ( s ) Action
171. Check ignition coils for cracks or carbon tracking.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 18
18Using  Tech  2,  monitor  the  TP  angle  with  the  engine
idling.
Is the TP angle at the specified value and steady?
0%Go to Step 19
Refer to DTC
P0123
 for
further
diagnosis
191. Check the PCV valve for proper operation.  Refer to
Crankcase Ventilation System.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 20
201. Check  the  transmission  range  switch  circuit.    Use
Tech 2 and be sure Tech 2 indicates that the vehicle
is in drive with the gear selector in drive or overdrive.
2. If  a  problem  is  found,  diagnose  and  repair  the
transmission  range  switch  as  necessary  (refer  to
4L30-E Automatic Transmission Diagnosis).
Was a problem found?
—Verify repairGo to Step 21
211. Check the following engine mechanical items.
Refer  to 
Engine  Mechanical  for  diagnosis
procedures:
Low compression
Sticking or leaking valves
Worn camshaft lobe(s)
Camshaft drive belt slipped or stripped
Incorrect valve timing
Worn rocker arms
Broken valve springs
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 22
221. Check  for  faulty  motor  mounts.    Refer  to Engine
Mechanical
 for inspection of mounts.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 23
231. Review all diagnostic procedures within this table.
2. If  all  procedures  have  been  completed  and  no
malfunctions  have  been  found,  review/inspect  the
following:
Visual/physical inspection
Te c h   2   d a t a
Freeze Frame data/Failure Records butter
All  electrical  connections  within  a  suspected
circuit and/or system
3. If a problem is found, repair as necessary.
Was a problem found?
—Verify repair
Contact
Te c h n i c a l
Assistance 
Page 1474 of 6000
6F–3 ENGINE EXHAUST
For Isuzu General Motors (IGM)
150RW058
When  inspecting  or  replacing  exhaust  system
components,  make  sure  there  is  adequate  clearance
from all points on the underbody to prevent overheating
the  floor  pan  and  possible  damage  to  the  passenger
compartment insulation and trim materials.
Check complete exhaust system and nearby body areas
and rear compartment lid for broken, damaged, missing
or  mispositioned  parts,  open  seams,  holes,  loose
connections  or  other  deterioration  which  could  permit
exhaust  fumes  to  seep  into  the  rear  compartment  or
passenger  compartment.  Dust  or  water  in  the  rear
compartment may be an indication of a problem in one of
these  areas.  Any  faulty  areas  should  be  corrected
immediately.
Hangers
Various  types  of  hangers  are  used  to  support  exhaust
system(s).  These  include  conventional  rubber  straps,
rubber rings, and rubber blocks.
The  installation  of  exhaust  system  supports  is  very
important,  as  improperly  installed  supports  can  cause
annoying vibrations which can be difficult to diagnose.
Three Way Catalytic Converter
The three way catalytic converter is an emission control
device added to the exhaust system to reduce pollutants
from the exhaust gas stream.
CAUTION: The catalytic converter requires the use
of unleaded fuel only.
Periodic  maintenance  of  the  exhaust  system  is  not
required.  If  the  vehicle  is  raised  for  other  service,  it  is
advisable to check the condition of the complete exhaust
system.
A  dual  bed  monolith  catalytic  converter  is  used  in
combination with three way catalytic converter.
Catalytic Types:
Three way (Reduction/Oxidation) catalyst
The  catalyst  coating  on  the  three  way  (reduction)
converter  contains  platinum  and  rhodium  which  lowers
the levels of nitrous oxide (NOx) as well as hydrocarbons
(HC) and carbon monoxide (Co).
Gasket
The  gasket  must  be  replaced  whenever  a  new  exhaust
pipe, muffler or catalytic converter is installed. 
Page 1500 of 6000
6J–2
INDUCTION
Air Cleaner Element
Removal
1. Remove positive ventilation hose from connector(1).
2. Remove intake air temperature sensor(2).
3. Remove air flow sensor(3).
4. Remove air cleaner duct cover(4).
5. Remove air cleaner element(5).
130RW003
Inspection
Check  the  air  cleaner  element  for  damage  or  dust
clogging. Replace if it is damaged, or clean if it is clogged.
Cleaning Method
Tap the air cleaner element gently so as not to damage
the paper element, or clean the element by blowing with
compressed air of about 490 kPa (71 psi) from the clean
side if it is extremely dirty.
130RW002
Installation
1. Install air cleaner element(5).
2. Attach  the  air  cleaner  duct  cover  (4)  to  the  body
completely, then clamp it with the clip.
3. Install mass air flow sensor(3).
4. Install air temperature sensor(2).
5. Connect  positive  crankcase  ventilation  hose  to
connector(1).
For General Export Model
130RW003
For Isuzu General Motors (IGM) Model
130RW006 
Page 1746 of 6000
ENGINE MECHANICAL 6A – 13
VALVE CLEARANCE ADJUSTMENT
1. Install  2.80  mm  valve  adjuster  (shim)  first  when
reassembling the engine.
Thickness mark faces down.
2. Measure  the  valve  clearance  after  installing  cam
carrier assy with camshafts.
3. Change  the  adjuster  using  a  special  tool  when  the
clearance is out of tolerance.
Valve Clearance Adjusting Tool: 5-8840-2590-0
VALVE CLEARANCE (When cold condition)
Inlet 0.15 ± 0.05 mm
Exh 0.25 ± 0.05 mm
COMPRESSION PRESSURE
MEASUREMENT
1. Start the engine and allow it to idle until the coolant
temperature reaches 70 – 80°C (158 – 176°F).
2. Remove the following parts.
Glow plugs
Fuel cut solenoid connector
QOS  (Quick-On  Start  System)  fuse  in  the  fuse
box.
3. Set the adapter and compression gauge to the No.
1 cylinder glow plug hole.
Compression Gauge 
(with Adapter): 5-8840-2008-0 
4. Turn the engine over with the starter motor and take
the compression gauge reading.
Compression Pressure at 200 rpm
Standard: 3040 kPa (31 kg/cm
2/441 psi)
Limit: 2160 kPa (22 kg/cm
2/313 psi)
5. Repeat  the  procedure  (Steps  3  and  4)  for  the
remaining cylinders.
QUICK-ON START 4 SYSTEM
Quick-On Start System Inspection Procedure
1. Disconnect  the  ECT-sensor  connection  around  the
thermostat outlet pipe.
2. Turn the starter switch to the “ON” position.
If  the  Quick-On  Start  4  System  is  operating
properly,  the  glow  relay  will  make  a  clicking  sound
within  seven  seconds  after  the  starter  switch  is
turned on.
3. Measure  the  glow  plug  terminal  voltage  with  a
circuit  tester  immediately  after  turning  the  starter
switch to the “ON” position.
Glow Plug Terminal Voltage: approx. 12V
NOTE: Electrical power to the quick-on start system will
be  cut  after  the  starter  has  remained  in  the  “ON”
position for twenty seconds.
Turn  the  starter  switch  to  the  “OFF”  position  and  back
to the “ON” position.
This will reset the Quick-On Start 4 System.
014RW150 
Page 1774 of 6000
ENGINE MECHANICAL 6A – 41
CYLINDER HEAD
3
4
1
2
012RW096
Legend
(1) Glow Plug
(2) Plate
(3) Cylinder Head Bolt
(4) Cylinder Head
NOTE: 
During  disassembly,  be  sure  that  the  valve  train
components  are  kept  together  and  identified  so  that
they can be re-installed in their original locations.
Before  removing  the  cylinder  head  from  the  engine
and  before  disassembling  the  valve  mechanism,  do
a compression test and note the results.
DISASSEMBLY
1. Injector Assy
2. Glow Plug and Glow Plug Connector 
3. Cylinder Head Assembly
Refer to “Cylinder Head Gasket”
CLEAN
Cylinder head
Carefully  remove  all  varnish,  soot  and  carbon  on
the  bare  metal.  Do  not  use  a  motorized  wire  brush
on any gasket sealing surface.
INSPECTION AND REPAIR
Make  the  necessary  adjustments,  repairs,  and  part
replacements  if  excessive  wear  or  damage  is
discovered during inspection.
1. Cylinder  head  gasket  and  mating  surfaces  for
leaks,  corrosion  and  blow-by.  If  the  gasket  has
failed, determine the cause;
– Improper installation
– Loosen or warped cylinder head
– Insufficient torque on head bolts
– Warped cylinder block surface 
Page 1793 of 6000
6A – 60 ENGINE MECHANICAL
VALVE STEM SEAL, VALVE SPRING AND ADJUSTER
REMOVAL
1. Disconnect battery ground cable.
2. Drain engine coolant.
3. Remove  the  air  duct  from  between  air  cleaner  and
turbocharger.
4. Remove intercooler assembly.
Refer to “Intercooler” in this manual.
5. Remove oil level gauge guide assembly.
6. Disconnect PCV hose.
7. Disconnect EGR vacuum hose.
8. Disconnect harness connectors around the cylinder
head  such  as  the  injector,  CMP sensor,  MAP
sensor,  EGR  sensor,  EVRV,  IAT sensor,  A/C
compressor, TP stepping motor, TP sensor and fuel
temperature sensor etc.
9. Remove A/C compressor assembly.
10. Remove A/C compressor bracket.
11. Remove  generator  assembly  and  take  out  drivebelt.
12. Remove  heat  protector,  remove  exhaust  valve
assembly.
13. Remove water cooling hose and lubrication pipe for
turbocharger.
14. Remove turbocharger assembly.
15. Remove hose between thermostat and radiator.
16. Remove noise insulator cover of cylinder head.
NOTE: Do not damage injector harness.
17. Remove high pressure oil pipe.
18. Remove timing belt cover.
19. Remove CMP sensor bracket.
20. Remove  timing  belt  tensioner  then  remove  timing
belt.
21. Remove camshaft pulley.
22. Remove front plate.
23. Remove  engine  coolant  pipe  between  cylinder
head and water pump.
1
2
3
4
5
6
9
10
7
8
011RW031
Legend
(1) Adjuster
(2) Tappet
(3) Split Collar
(4) Spring Seat Upper
(5) Valve Spring(6) Spring Seat Lower
(7) Valve Stem Seal
(8) Valve  Guide
(9) Valve Seat
(10) Valve