engine oil OPEL FRONTERA 1998 Workshop Manual
[x] Cancel search | Manufacturer: OPEL, Model Year: 1998, Model line: FRONTERA, Model: OPEL FRONTERA 1998Pages: 6000, PDF Size: 97 MB
Page 1332 of 6000

6E–215 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0354 Ignition 4 Control Circuit
D06RW072
Circuit Description
The powertrain control module’s (PCM) control circuit 4
provides a zero-volt or a 5-volt output signal to the ignition
coil.  The normal voltage on the circuit is zero volts.  When
the ignition coil receives the 5-volt signal from the PCM, it
provides a ground path for the B+ supply to the primary
side of the number 4 ignition coil.  When the PCM shuts off
the 5 volts to the ignition coil, the ignition coil turns “OFF.”
This  causes  the  ignition  coil  primary  magnetic  field  to
collapse, producing a voltage in the secondary coil which
fires the spark plug.
The circuit between the PCM and ignition coil is monitored
for an open circuit, short to voltage, and short to ground.
When  the  PCM  detects  a  problem  on  ignition  control
circuit 4, it will set a DTC P0354.
Conditions for Setting the DTC
The ignition is “ON.”
The  engine  is  turning,  determined  by  the  58X
crankshaft position input signal.
The output voltage is not equal to 5 volts when output
is “ON.”
The output voltage is not equal to 0 volts when output
is “OFF.”
Twenty  test  failures  occur  within  40  samples  of
continuous spark events.
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 P0354 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: 
Page 1333 of 6000

6E–216
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 P0354 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 P0354 – Ignition 4 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 P0354 until the DTC P0354 test
runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0354 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 4 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 4 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 4 for short to ground.
Was a problem found?
—Verify repairGo to Step 10
10Check ignition control circuit 4 for short to voltage.
Was a problem found?
—Verify repairGo to Step 13 
Page 1335 of 6000

6E–218
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0355 Ignition 5 Control Circuit
D06RW072
Circuit Description
The powertrain control module’s (PCM) control circuit 5
provides a zero-volt or a 5-volt output signal to the ignition
coil.  The normal voltage on the circuit is zero volts.  When
the ignition coil receives the 5-volt signal from the PCM, it
provides a ground path for the B+ supply to the primary
side of the number 5 ignition coil.  When the PCM shuts off
the 5 volts to the ignition coil, the ignition coil turns “OFF.”
This  causes  the  ignition  coil  primary  magnetic  field  to
collapse, producing a voltage in the secondary coil which
fires the spark plug.
The circuit between the PCM and ignition coil is monitored
for an open circuit, short to voltage, and short to ground.
When  the  PCM  detects  a  problem  on  ignition  control
circuit 5, it will set a DTC P0355.
Conditions for Setting the DTC
The ignition is “ON.”
The  engine  is  turning,  determined  by  the  58X
crankshaft position input signal.
The output voltage is not equal to 5 volts when output
is “ON.”
The output voltage is not equal to 0 volts when output
is “OFF.”
Twenty  test  failures  occur  within  40  samples  of
continuous spark events.
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 P0355 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: 
Page 1336 of 6000

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 
Page 1338 of 6000

6E–221 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0356 Ignition 6 Control Circuit
D06RW072
Circuit Description
The powertrain control module’s (PCM) control circuit 6
provides a zero-volt or a 5-volt output signal to the ignition
coil.  The normal voltage on the circuit is zero volts.  When
the ignition coil receives the 5-volt signal from the PCM, it
provides a ground path for the B+ supply to the primary
side of the number 6 ignition coil.  When the PCM shuts off
the 5 volts to the ignition coil, the ignition coil turns “OFF.”
This  causes  the  ignition  coil  primary  magnetic  field  to
collapse, producing a voltage in the secondary coil which
fires the spark plug.
The circuit between the PCM and ignition coil is monitored
for an open circuit, short to voltage, and short to ground.
When  the  PCM  detects  a  problem  on  ignition  control
circuit 6, it will set a DTC P0356.
Conditions for Setting the DTC
The ignition is “ON.”
The  engine  is  turning,  determined  by  the  58X
crankshaft position input signal.
The output voltage is not equal to 5 volts when output
is “ON.”
The output voltage is not equal to 0 volts when output
is “OFF.”
Twenty  test  failures  occur  within  40  samples  of
continuous circuit monitoring.
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 P0356 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: 
Page 1339 of 6000

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 
Page 1360 of 6000

6E–243 ENGINE DRIVEABILITY AND EMISSIONS
DTC P1154 – HO2S Transition Time Ratio Bank 2 Sensor 1
StepNo Ye s Va l u e ( s ) Action
12Check for leaks at the exhaust manifold.
Are there leaks at the exhaust manifold?
—Go to Step 13Go to Step 14
13Tighten  the  bolts  to  specifications  or  replace  the
manifold if necessary.
Is your action complete?
—Go to Step 2—
14Visually/physically inspect the following items:
Ensure  that  the  Bank  2  HO2S  1  is  securely
installed.
Check for corrosion on terminals.
Check terminal tension (at Bank 2 HO2S 1 and at
the PCM).
Check for damaged wiring.
Was a problem found in any of the above areas?
—Go to Step 18Go to Step 15
151. Disconnect Bank 1 HO2S 1.
2. Ignition “ON.”
3. Using  a  DVM  at  the  PCM  side  of  the  HO2S  1
connector,  measure  the  voltage  between  the  high
signal circuit and ground.
Also measure the voltage between the low signal
circuit and ground.
Are both voltages in the specified range?
3-4 V
Go to Step
16
Go to Step 19
161. With Bank 1 HO2S 1 disconnected, jumper the high
and low (PCM side) signal circuits to ground.
2. Ignition “ON.”
3. Using Tech 2, monitor the Bank 2 HO2S 1 voltage.
Does  the  scan  too  indicate  less  than  10  mV  and
immediately return to about 450 mV when the jumper is
removed?
—Go to Step 21Go to Step 22
17Replace affected heated oxygen sensors.
NOTE: Before  replacing  sensors,  the  cause  of  the
contamination must be determined and corrected.
Fuel contamination.
Use of improper RTV sealant.
Engine oil/coolant consumption.
Is the action complete?
—Verify repair—
18Repair condition as necessary.
Is the action complete?
—Verify repair—
19Check for faulty PCM connections or terminal damage.
Is the action complete?
—Verify repairGo to Step 20
20Repair open, short or grounded signal circuit.
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 1379 of 6000

6E–262
ENGINE DRIVEABILITY AND EMISSIONS
Symptom Diagnosis
Preliminary Checks
Before  using  this  section,  perform  the  “On-Board
Diagnostic  (OBD)  System  Check”  and  verify  all  of  the
following items:
The powertrain control module (PCM) and malfunction
indicator lamp (MIL) (Service Engine Soon lamp) are
operating correctly.
There are no DTC(s) stored.
Tech 2 data is within normal operating range.  Refer to
Typical Scan Data Values.
Verify  the  customer  complaint  and  locate  the  correct
symptom  in  the  table  of  contents.    Perform  the
procedure included in the symptom chart.
Visual/Physical Check
Several  of  the  symptom  procedures  call  for  a  careful
visual/physical  check.    This  can  lead  to  correcting  a
problem  without  further  checks  and  can  save  valuable
time.
This check should include the following items:
PCM  grounds  for  cleanliness,  tightness  and  proper
location.
Vacuum  hoses  for  splits,  kinks,  and  proper
connections,  as  shown  on  the  “Vehicle  Emission
Control  Information”  label.   Check thoroughly  for  any
type of leak or restriction.
Air intake ducts for collapsed or damaged areas.
Air leaks at throttle body mounting area, mass air flow
(MAF) sensor and intake manifold sealing surfaces.
Ignition  wires  for  cracking,  hardness,  and  carbon
tracking.
Wiring for proper connections, pinches and cuts.
Intermittents
IMPORTANT:An intermittent problem may or may not
turn  on  the  malfunction  indicator  lamp  (MIL)  or  store  a
DTC.  DO NOT use the Diagnostic Trouble Code (DTC)
charts  for  intermittent  problems.    The  fault  must  be
present to locate the problem.
Most intermittent problems are caused by faulty electrical
connections or wiring.  Perform a careful visual/physical
check for the following conditions:
Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).
Improperly formed or damaged terminal.
All connector terminals in the problem circuit should be
carefully checked for proper contact tension.
Poor  terminal-to-wire  connection.    This  requires
removing  the  terminal  from  the  connector  body  to
check.
Road  test  the  vehicle  with  a  J  39200  Digital  Multimeter
connected to  a  suspected circuit.  An  abnormal  voltage
when  the  malfunction  occurs  is  a  good  indication  that
there is a fault in the circuit being monitored.
Use Tech 2 to help detect intermittent conditions.  Tech 2s
have  several  features  that  can  be  used  to  locate  anintermittent  condition.    Use  the  following  feature  to  find
intermittent faults:
Using  Tech  2’s  “Freeze  Frame”  buffer  or  “Failure
Records”  buffer  can  aid  in  locating  an  intermittent
condition.    Review  and  record  the  information  in  the
freeze  frame  or  failure  record  associated  with  the
intermittent DTC being diagnosed.  The vehicle can be
driven within the conditions that were present when the
DTC originally set.
To check for loss of diagnostic code memory, disconnect
the MAP sensor and idle the engine until the MIL (Service
Engine  Soon  lamp)  comes  on.    DTC  P0107  should  be
stored  and  kept  in  memory  when  the  ignition  is  turned
“OFF.”    If  not,  the  PCM  is  faulty.    When  this  test  is
completed, make sure that you clear the DTC P0107 from
memory.
An intermittent MIL (Service Engine Soon lamp) with no
stored DTC may be caused by the following:
Ignition  coil  shorted  to  ground  and  arcing  at  ignition
wires or plugs.
MIL (Service Engine Soon lamp) wire to PCM shorted
to ground.
Poor  PCM  grounds.    Refer  to  the  PCM  wiring
diagrams.
Check for improper installation of electrical options such
as lights, cellular phones, etc.  Route ignition coil wiring
away from the ignition coils.  Check all wires from the
PCM to the ignition coil for poor connections.
Check  for  an  open  diode  across  the  A/C  compressor
clutch  and  check  for  other  open  diodes  (refer  to  wiring
diagrams in 
Electrical Diagnosis).
If problem has not been found, refer to 
PCM Connector
Symptom
 tables.