air filter OPEL FRONTERA 1998 Manual PDF
Page 4609 of 6000
6C–2
ENGINE FUEL
General Description
140RW030
Legend
(1) Fuel Filler Cap
(2) Fuel Tank
(3) Rollover Valve
(4) Fuel Pump
(5) Fuel Filter
(6) Fuel Rail Right
(7) Right Bank(8) Fuel Rail Left
(9) Left Bank
(10) Fuel Pressure Control Valve
(11) Common Chamber
(12) Duty Solenoid Valve
(13) Throttle Valve
(14) Canister
When  working  on  the  fuel  system,  there  are  several
things to keep in mind:
Any  time  the  fuel  system  is  being  worked  on,
disconnect  the  negative  battery  cable  except  for
those tests where battery voltage is required.
Always  keep  a  dry  chemical  (Class  B)  fire
extinguisher near the work area.
Replace all pipes with the same pipe and fittings that
were removed.
Clean and inspect “O” rings. Replace if required.
Always relieve the line pressure before servicing any
fuel system components.
Do not attempt repairs on the fuel system until you
have read the instructions and checked the pictures
relating to that repair. 
Page 4611 of 6000
6C–4
ENGINE FUEL
Fuel Filter
Fuel Filter and Associated Parts
041RW014
Legend
(1) Fuel Filler Cap
(2) Fuel Hose(3) Fuel Filter Fixing Bolt
(4) Fuel Filter
Removal
CAUTION: When repair to the fuel system has been
completed,  start  engine  and  check  the  fuel  system
for loose connection or leakage. For the fuel system
diagnosis, see Section “Driveability and Emission”.
1. Disconnect battery ground cable.
2. Remove Fuel filler cap(1).
3. Disconnect  fuel  hoses(2) from  fuel  filter  on  both
engine side and fuel tank side.
4. Fuel filter fixing bolt(3).
Remove  the  fuel  filter  fixing  bolt(3)  on  fuel  filter
holder.
5. Remove fuel filter(4).
Inspection
1. Replace the fuel filter if the fuel leaks from fuel filter
body or if the fuel filter body itself is damaged.
2. Replace the filter if it is clogged with dirt or sediment.
3. Check the drain of receive rubber and if it is clogged
with dust, clean it up with air. 
Page 4660 of 6000
6E–3 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0351
 Ignition 1 Control Circuit 6E–206. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0352
 Ignition 2 Control Circuit 6E–209. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0353
 Ignition 3 Control Circuit 6E–212. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0354
 Ignition 4 Control Circuit 6E–215. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0355
 Ignition 5 Control Circuit 6E–218. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0356
 Ignition 6 Control Circuit 6E–221. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0402
 EGR Pintle Crank Error 6E–224. . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0404
 EGR Open Stuck 6E–226. . . . . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0405
 EGR Low Voltage 6E–228. . . . . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0406 
 EGR High Voltage 6E–231. . . . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0502
 VSS Circuit Low Input 6E–234. . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0562
 System Voltage Low 6E–237. . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0563
 System Voltage High 6E–239. . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P0601
 PCM Memory 6E–240. . . . . . . . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P1154
 HO2S Circuit Transition Time Ratio Bank 2
 Sensor 1 6E–241. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P1171
 Fuel System Lean During Acceleration 6E–245. . . . 
Diagnostic Trouble Code (DTC) P1380
 ABS Rough Road ABS System Fault 6E–248. . . . . . 
Diagnostic Trouble Code (DTC) P1404
 EGR Closed Stuck 6E–249. . . . . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P1508
 IAC System Low RPM 6E–251. . . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P1509
 IAC System High RPM 6E–254. . . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P1618
 Serial Peripheral Interface (SPI) PCM
 Interprocessor Communication Error 6E–257. . . . . . 
Diagnostic Trouble Code (DTC) P1625
 PCM Unexpected Reset 6E–258. . . . . . . . . . . . . . . . . 
Diagnostic Trouble Code (DTC) P1640
 Driver-1-Input High Voltage 6E–259. . . . . . . . . . . . . . 
Symptom Diagnosis 6E–262. . . . . . . . . . . . . . . . . . . . . 
Default Matrix Table 6E–288. . . . . . . . . . . . . . . . . . . . . 
Camshaft Position (CMP) Sensor 6E–291. . . . . . . . . . 
Crankshaft Position (CKP) Sensor 6E–292. . . . . . . . . 
Engine Coolant Temperature (ECT) Sensor 6E–292. 
Heated Oxygen Sensor (HO2S) 6E–293. . . . . . . . . . . 
Intake Air Temperature (IAT) Sensor 6E–295. . . . . . . 
Knock Sensor (KS) 6E–296. . . . . . . . . . . . . . . . . . . . . . Mass Air Flow (MAF) Sensor 6E–297. . . . . . . . . . . . . 
Manifold Absolute Pressure (MAP) Sensor 6E–297. 
Malfunction Indicator Lamp (MIL) 6E–298. . . . . . . . . . 
Powertrain Control Module (PCM) 6E–298. . . . . . . . . 
EEPROM 6E–300. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Power Steering Pressure (PSP) Switch 6E–300
. . . . 
Throttle Position (TP) Sensor 6E–301. . . . . . . . . . . . . 
Vehicle Speed Sensor (VSS) 6E–302. . . . . . . . . . . . . 
Air Cleaner/Air Filter 6E–303. . . . . . . . . . . . . . . . . . . . . 
Idle Air Control (IAC) Valve 6E–304. . . . . . . . . . . . . . . 
Common Chamber 6E–305. . . . . . . . . . . . . . . . . . . . . . 
Accelerator Cable Assembly 6E–305. . . . . . . . . . . . . . 
Accelerator Pedal Replacement 6E–308. . . . . . . . . . . 
Fuel Filter Cap 6E–310. . . . . . . . . . . . . . . . . . . . . . . . . . 
Fuel Filter 6E–310. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Fuel Gauge Unit 6E–313. . . . . . . . . . . . . . . . . . . . . . . . 
Fuel Injectors 6E–314. . . . . . . . . . . . . . . . . . . . . . . . . . . 
Fuel Pressure Regulator 6E–315. . . . . . . . . . . . . . . . . 
Fuel Metering System 6E–317. . . . . . . . . . . . . . . . . . . . 
Fuel Pump Assembly 6E–318. . . . . . . . . . . . . . . . . . . . 
Fuel Pump Relay 6E–319. . . . . . . . . . . . . . . . . . . . . . . . 
Fuel Rail Assembly 6E–319. . . . . . . . . . . . . . . . . . . . . . 
Fuel Tank 6E–321. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Throttle Body (TB) 6E–323. . . . . . . . . . . . . . . . . . . . . . . 
Electronic Ignition System 6E–324. . . . . . . . . . . . . . . . 
Catalytic Converter 6E–325. . . . . . . . . . . . . . . . . . . . . . 
Air Conditioning Relay 6E–325. . . . . . . . . . . . . . . . . . . 
EVAP Canister Hoses 6E–326. . . . . . . . . . . . . . . . . . . . 
EVAP Canister 6E–326. . . . . . . . . . . . . . . . . . . . . . . . . . 
EVAP Canister Purge Solenoid 6E–327. . . . . . . . . . . . 
Fuel Tank Vent Valve 6E–328. . . . . . . . . . . . . . . . . . . . 
Linear Exhaust Gas Recirculation
 (EGR) Valve 6E–328. . . . . . . . . . . . . . . . . . . . . . . . . . . 
Positive Crankcase Ventilation (PCV) Valve 6E–329. 
Wiring and Connectors 6E–330. . . . . . . . . . . . . . . . . . . 
PCM Connectors and Terminals 6E–330. . . . . . . . . . . 
Wire Harness Repair: Twisted Shielded
 Cable 6E–330. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Twisted Leads 6E–331. . . . . . . . . . . . . . . . . . . . . . . . . . 
Weather-Pack Connector 6E–332. . . . . . . . . . . . . . . . . 
Com-Pack III 6E–333. . . . . . . . . . . . . . . . . . . . . . . . . . . 
Metri-Pack 6E–333. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
General Description 6E–335. . . . . . . . . . . . . . . . . . . . . 
General Description (PCM and Sensors) 6E–335. . . 
58X Reference PCM Input 6E–335. . . . . . . . . . . . . . 
A/C Request Signal 6E–335. . . . . . . . . . . . . . . . . . . . 
Crankshaft Position (CKP) Sensor 6E–335. . . . . . . 
Camshaft Position (CMP) Sensor and
 Signal 6E–335. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Engine Coolant Temperature (ECT) Sensor 6E–335
Electrically Erasable Programmable Read
 Only Memory (EEPROM) 6E–336. . . . . . . . . . . . . . 
Fuel Control Heated Oxygen Sensors 6E–336. . . . 
Intake Air Temperature (IAT) Sensor 6E–336. . . . .  
Page 4686 of 6000
6E–29 ENGINE DRIVEABILITY AND EMISSIONS
Engine Component Locator Table
Number
NameLocation
1Linear Exhaust Gas Recirculation (EGR) ValveRear right side of the engine
2Throttle Position (TP) SensorOn the rear of the throttle body
3Intake Air Temperature (IAT) SensorOn the intake air duct near the throttle body
4Check Engine (MIL) LightOn the instrument panel beneath the
tachometer
5Positive Crankcase Ventilation (PCV) ValveOn the left of the cylinder head cover
6Air CleanerLeft front of the engine bay
7Mass Air Flow (MAF) SensorAttached to the air filter box
8Camshaft Position (CMP) SensorOn the rear right side at the left of the cylinder
head cover
9Fuel Pressure RegulatorRear right side of the engine
10Idle Air Control (IAC) ValveOn the left of the throttle body
11Upper Intake ManifoldTop of the engine
12Fuse/Relay BoxAlong the inside of the right fender
13Manifold Absolute Pressure (MAP) SensorBolted to the top of the upper intake manifold
14Throttle BodyBetween the intake air duct and the upper
intake manifold
15Engine Coolant Temperature SensorOn the coolant crossover pipe at the front of
the engine, near the throttle body 
Page 4688 of 6000
6E–31 ENGINE DRIVEABILITY AND EMISSIONS
Engine Component Locator Table
Number
NameLocation
1Linear Exhaust Gas Recirculation (EGR) ValveRear right side of the engine
2Throttle Position (TP) SensorOn the rear of the throttle body
3Intake Air Temperature (IAT) SensorOn the intake air duct near the throttle body
4Check Engine (MIL) LightOn the instrument panel beneath the
tachometer
5Positive Crankcase Ventilation (PCV) ValveOn the left of the cylinder head cover
6Air CleanerLeft front of the engine bay
7Mass Air Flow (MAF) SensorAttached to the air filter box
8Camshaft Position (CMP) SensorOn the rear right side at the left of the cylinder
head cover
9Fuel Pressure RegulatorRear right side of the engine
10Idle Air Control (IAC) ValveOn the left of the throttle body
11Upper Intake ManifoldTop of the engine
12Fuse/Relay BoxAlong the inside of the right fender
13Manifold Absolute Pressure (MAP) SensorBolted to the top of the upper intake manifold
14Throttle BodyBetween the intake air duct and the upper
intake manifold
15Engine Coolant Temperature SensorOn the coolant crossover pipe at the front of
the engine, near the throttle body 
Page 4695 of 6000
6E–38
ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
OBD Serviceablity Issues
The  list  of  non-vehicle  faults  that  could  affect  the
performance  of  the  OBD  system  has  been  compiled.
These  non-vehicle  faults  vary  from  environmental
conditions to the quality of fuel used.
The illumination of the MIL (“Check Engine” lamp) due to
a  non-vehicle  fault  could  lead  to  misdiagnosis  of  the
vehicle,  increased  warranty  expense  and  customer
dissatisfaction.    The  following  list  of  non-vehicle  faults
does not include every possible fault and may not apply
equally to all product lines.
Fuel Quality
Using fuel with the wrong octane rating for your vehicle
may cause driveability problems.  Many of the major fuel
companies  advertise  that  using  “premium”  gasoline  will
improve the performance of your vehicle.  Most premium
fuels use alcohol to increase the octane rating of the fuel.
Although  alcohol-enhanced  fuels  may  raise  the  octane
rating,  the  fuel’s  ability  to  turn  into  vapor  in  cold
temperatures  deteriorates.    This  may  affect  the  starting
ability and cold driveability of the engine.
Low  fuel  levels  can  lead  to  fuel  starvation,  lean  engine
operation, and eventually engine misfire.
Non-OEM Parts
All  of  the  OBD  diagnostics  have  been  calibrated  to  run
with OEM parts.  Something as simple as a
high-performance  exhaust  system  that  affects  exhaust
system back pressure could potentially interfere with the
operation of the EGR valve and thereby turn on the MIL
(“Check  Engine”  lamp).    Small  leaks  in  the  exhaust
system  near  the  post  catalyst  oxygen  sensor  can  also
cause the MIL (“Check Engine” lamp) to turn on.
Aftermarket  electronics,  such  as  cellular  phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed.  This may
cause a false sensor reading and turn on the MIL (“Check
Engine” lamp).
Environment
Temporary  environmental  conditions,  such  as  localized
flooding, will have an effect on the vehicle ignition system.
If  the  ignition  system  is  rain-soaked,  it  can  temporarily
cause engine misfire and turn on the MIL (“Check Engine”
lamp).
Poor Vehicle Maintenance
The  sensitivity  of  OBD  diagnostics  will  cause  the  MIL
(“Check  Engine”  lamp)  to  turn  on  if  the  vehicle  is  not
maintained properly.  Restricted air filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously  monitored  prior  to  OBD.    Poor  vehicle
maintenance  can  not  be  classified  as  a  “non-vehicle
fault”, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.Related System Faults
Many  of  the  OBD  system  diagnostics  will  not  run  if  the
PCM detects a fault on a related system or component.
One example would be that if the PCM detected a Misfire
fault, the diagnostics on the catalytic converter would be
suspended until Misfire fault was repaired.  If the Misfire
fault was severe enough, the catalytic converter could be
damaged  due  to  overheating  and  would  never  set  a
Catalyst DTC until the Misfire fault was repaired and the
Catalyst diagnostic was allowed to run to completion.  If
this happens, the customer may have to make two trips to
the dealership in order to repair the vehicle.
Maintenance Schedule
Refer to the Maintenance Schedule.
Visual / Physical Engine Compartment
Inspection
Perform  a  careful    visual  and  physical  engine
compartment inspection when performing any diagnostic
procedure  or  diagnosing  the  cause  of  an  emission  test
failure.  This can often lead to repairing a problem without
further  steps.    Use  the  following  guidelines  when
performing a visual/physical inspection:
Inspect  all  vacuum  hoses  for  punches,  cuts,
disconnects, and correct routing.
Inspect  hoses  that  are  difficult  to  see  behind  other
components.
Inspect all wires in the engine compartment for proper
connections,  burned  or  chafed  spots,  pinched  wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing  diagnostic  procedures  could  result  in  an
incorrect  diagnosis  or  damage  to  powertrain
components.    Do  not  attempt  to  diagnose  a  powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the “Class II” communication system.
Each bit of information can have one of two lengths: long
or  short.    This  allows  vehicle  wiring  to  be  reduced  by
transmitting and receiving multiple signals over a single
wire.  The messages carried on Class II data streams are
also  prioritized.    If  two  messages  attempt  to  establish
communications on the data line at the same time, only
the message with higher priority will continue.  The device
with  the  lower  priority  message  must  wait.    The  most
significant result of this regulation is that it provides Tech 2
manufacturers with the capability to access data from any
make or model vehicle that is sold. 
Page 4737 of 6000
6E–80
ENGINE DRIVEABILITY AND EMISSIONS
Circuit Description
The electronic Ignition system uses a coil-at-plug method
of spark distribution.  In this type of ignition system, the
powertrain  control  module  (PCM)  triggers  the  correct
driver  inside  the  ignition  coil,  which  then  triggers  the
correct ignition coil based on the 58X signal received from
the  crankshaft  position  sensor  (CKP).    The  spark  plug
connected to the coil fires when the ICM opens the ground
circuit for the coil’s primary circuit.
During crank, the PCM monitors the CKP 58X signal.  The
CKP  signal  is  used  to  determine  which  cylinder  will  fire
first.  After the CKP 58X signal has been processed by the
PCM, it will command all six injectors to allow a priming
shot  of  fuel  for  all  the  cylinders.    After  the  priming,  the
injectors are left “OFF” during the next six 58X reference
pulses from the CKP.  This allows each cylinder a chance
to use the fuel from the priming shot.  During this waiting
period, a camshaft position (CMP) signal pulse will have
been received by the PCM.  The CMP signal allows the
PCM  to  operate  the  injectors  sequentially  based  on
camshaft position.  If the camshaft position signal is not
present  at  start-up,  the  PCM  will  begin  sequential  fuel
delivery with a 1-in-6 chance that fuel delivery is correct.
The  engine  will  run without  a CMP  signal,  but  will set  a
DTC code.
Diagnostic Aids
An  intermittent  problem  may  be  caused  by  a  poor
connection,  rubbed-through  wire  insulation  or  a  wire
broken  inside  the  insulation.    Check  for  the  following
items:
Poor  connection  or  damaged  harness  –  Inspect  the
PCM  harness  and  connectors  for  improper  mating,
broken  locks,  improperly  formed  or  damaged
terminals,  poor  terminal-to-wire  connection,  and
damaged harness.
Faulty  engine  coolant  temperature  sensor  –  Using
Tech  2,  compare  engine  coolant  temperature  with
intake  air  temperature  on  a  completely  cool  engine.
Engine coolant temperature should be within 10
C of
intake air temperature.  If not, replace the ECT sensor.
Test Description
Number(s)  below  refer  to  the  step  number(s)  on  the
Diagnostic Chart.
5. An obvious cause of low fuel pressure would be an
empty fuel tank.
6. The engine will easily start and run if a few injectors
are disabled.  It is not necessary to test all injectors
at this time since this step is only a test to verify that
all of the injectors have not been disabled by fuel
contamination.
7. A blinking test light verifies that the PCM is
monitoring the 58X crankshaft reference signal and
is capable of activating the injectors.  If there is an
open or shorted driver circuit, DTCs 201-206 should
be set.
19.By using a spark tester, each ignition coil’s ability to
produce 25,000 volts is verified.
25.If there is an open or shorted driver circuit, DTCs
201-206 should be set.  All six injector driver circuits
can be checked at one time without removing the
intake manifold if a 5-8840-2636-0 test light is
available.  This is the alternative procedure:
With the ignition “OFF,” disconnect the gray
connector located at the rear of the air filter, attached
to a bracket on the purge canister.
Connect test light 5-8840-2636-0 to the connector.
Do any of the light constantly illuminate or fail to blink
when the engine is cranked?  If so, repair the short or
open circuit, or replace the PCM if indicated.
This procedure only tests the driver circuit as far as the
test connection, so step 31 is added to test the circuit all
the way to the injector. 
Page 4738 of 6000
6E–81 ENGINE DRIVEABILITY AND EMISSIONS
Engine Cranks But Will Not Run
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
2Check the 15 A ignition coil fuse, the 15 A engine fuse,
and the 30 A PCM fuse.
Was a fuse blown?
—Go to Step 3Go to Step 4
3Check for a short to ground and replace the fuse.
Is the action complete?
—Verify repair—
41. Ignition “OFF,” install a fuel pressure gauge at the
test  fitting  on  the  fuel  supply  line  in  the  engine
compartment.  (Use a shop cloth to absorb any fuel
leakage while making the connection.)
2. Ignition “ON,” observe the fuel pressure.
Is  the  fuel  pressure  within  the  specified  values,  and
does it hold steady?
285-376 kPa
(43-55 psi)
Go to Step 6Go to Step 5
5Is any fuel pressure indicated?
—
Go to Fuel
System
Electrical TestGo to Fuel
System
Diagnosis
6Install  an  injector  switch  box  to  the  injector  test
connector, and attempt to operate the injector.
Did  the  fuel  pressure  drop  when  the  injector  is
operated?
—Go to Step 7Go to Step 12
7Install  an  injector  test  light  at  the  #2  cylinder  injector
harness connector.
Does the light blink when the engine is cranked?
—Go to Step 8Go to Step 18
81. Ignition “ON.”
2. While the coil connectors are disconnected, touch
each  coil  connector’s  ignition  feed  terminal  with  a
grounded  test  light  (the  ignition  feed  wire  is  black
with orange tracer).
Did the test light illuminate?
—Go to Step 10Go to Step 9
9Repair the open ignition feed circuit.
Is the action complete?
—Verify repair—
10While  the  coil  connectors  are  disconnected,  touch
each  connector’s  secondary  ground  terminal  with  a
test light to B+.  (The ground wires are black.)
Did the test light illuminate at each coil connector?
—Go to Step 12Go to Step 11
11Repair the open secondary ground circuit.
Is the action complete?
—Verify repair—
121. Test the fuel for contamination.
2. If  a  problem  is  found,  clean  the  fuel  system  and
correct  the  contaminated  fuel  condition  as
necessary.  Replace the fuel filter and replace any
injectors  that  are  not  delivering  fuel  (see  Injector
Balance Test).
Was a problem found?
—Verify repairGo to Step 13 
Page 4739 of 6000
6E–82
ENGINE DRIVEABILITY AND EMISSIONS
Engine Cranks But Will Not Run
StepNo Ye s Va l u e ( s ) Action
131. Remove any ignition coil and install a spark tester at
the spark plug end of the coil.
2. Observe the tester while the engine is cranking.
Was  a  crisp,  blue  spark  observed?    Only  one  or  two
sparks followed by no result is considered the same as
“No Spark.”
—Go to Step 15Go to Step 14
14Replace the ignition coil, and return to Step 13 to test
the remaining coils.
Is the action complete?
—Verify repair—
15Repeat Step 13 for each coil.  Remove only one coil at a
time,  and  reinstall  each  coil  on  its  spark  plug  after
testing,  but  do  not  refasten  coils  with  screws  at  this
time.
After  all  coils  have  passed  the  spark  test,  does  the
engine start?
—
Refasten all
coils with
their screws
Go to Step 16
161. Remove the spark plugs from all cylinders.
2. Visually inspect the spark plug electrodes.
3. Replace  any  spark  plugs  with  loose  or  missing
electrodes or cracked insulators.
Did your  inspection  reveal  any  spark  plugs  exhibiting
excessive fouling?
—
Correct the
fouling
condition
Go to Step 17
17Refer to Engine Mechanical Diagnosis to diagnose the
following conditions:
Faulty or incorrect camshaft drive belts
Leaking or sticky valves or rings
Excessive valve deposits
Loose or worn rocker arms
Weak valve springs
Incorrect valve timing
Leaking head gasket
Is the action complete?
—Verify repairGo to Step 19
18Observe the “Engine Speed” data display on the scan
tool while cranking the engine.
Is  the  engine  RPM  indicated?    (If  the  scan  tool  is
normally powered from the cigarette lighter socket, and
if the scan tool display goes blank while cranking  the
engine,  it  will  be  necessary  to  power  the  scan  tool
directly from the vehicle battery.)
—Go to Step 19Go to Step 28
191. Disconnect the 7-pin gray connector at the rear of
the  air  filter  beneath  the  point  where  the  air  duct
attaches to the MAF sensor.
2. Ignition “ON.”
3. Using  a  test  light  connected  to  ground,  probe  the
ignition  terminal  at  the  PCM  (female)  side  of  the
7-pin connector.
Is the test light “ON?”
—Go to Step 20Go to Step 26 
Page 4747 of 6000
6E–90
ENGINE DRIVEABILITY AND EMISSIONS
Fuel System Diagnosis
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. Turn the ignition “OFF.”
2. Turn the air conditioning system “OFF.”
3. Relieve  fuel  system  pressure  and  install  the  fuel
pressure gauge.
4. Turn the ignition “ON.”
NOTE: The  fuel  pump  will  run  for  approximately  2
seconds.  Use Tech 2 to command the fuel pump “ON”.
5. Observe  the  fuel  pressure  indicated  by  the  fuel
pressure gauge with the fuel pump running.
Is the fuel pressure within the specified limits?
290-376 kPa
(42-55 psi)
Go to Step 3Go to Step 17
3NOTE: The fuel pressure will drop when the fuel pump
stops  running,  then  it  should  stabilize  and  remain
constant.
Does the fuel pressure indicated by the fuel pressure
gauge remain constant?
—Go to Step 4Go to Step 12
41. When  the  vehicle  is  at  normal  operation
temperature,  turn  the  ignition  “ON”  to  build  fuel
pressure  and  observe  the  measurement  on  the
gauge.
2. Start  the  engine  and  observe  the  fuel  pressure
gauge.
Did the reading drop by the amount specified after the
engine was started?
21-105 kPa
(3-15 psi)
Go to Step 5Go to Step 9
5Is  fuel  pressure  dropping  off  during  acceleration,
cruise, or hard cornering?
—Go to Step 6
Check for
improper fuel
6Visually and physically inspect the following items for a
restriction:
The in-pipe fuel filter.
The fuel feed line.
Was a restriction found?
—Verify repairGo to Step 7
7Remove  the  fuel  tank  and  visually  and  physically
inspect the following items:
The fuel pump strainer for a restriction.
The fuel line for a leak.
Verify that the correct fuel pump is in the vehicle.
Was a problem found in any of these areas?
—Verify repairGo to Step 8
8Replace the fuel pump.
Is the action complete?
—Verify repair—
91. Disconnect the vacuum hose from the fuel pressure
regulator.
2. With  the  engine  idling,  apply  12-14  inches  of
vacuum to the fuel pressure regulator.
Does the fuel pressure indicated by the fuel pressure
gauge drop by the amount specified?
21-105 kPa
(3-15 psi)
Go to Step 10Go to Step 11