1998 OPEL FRONTERA ECU

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–277 ENGINE DRIVEABILITY AND EMISSIONS
Excessive Exhaust Emissions or Odors Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Vehicle fails an emission test. Vehicle has excessive
“rotten egg” smell. (Excessive odors do not necessarily
indicate excessive emissions.)
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Go to Step 12Go to Step 3
3Was a thorough visual/physical check performed?
—Go to Step 4
Go to
Visual/Physic
al Check
41. Check for vacuum leaks. Check vacuum lines,
intake manifold, throttle body, etc.
2. If a problem is found, repair as necessary.
Were any vacuum leaks located?
—Go to Step 12Go to Step 5
51. Check the fuel cap for proper installation.
2. Secure the fuel cap if necessary.
Was the fuel cap installed properly?
—Go to Step 6Go to Step 12
61. Check the fuel pressure. Perform the procedure in
Fuel System Pressure Test.
2. If a problem is found, repair as necessary.
Was a problem found?
—Go to Step 12Go to Step 7
71. Check for a faulty, plugged, or incorrectly installed
crankcase ventilation valve; also check the
crankcase ventilation system for plugging.
2. If a problem is found, repair as necessary.
Was a problem found?
—Go to Step 12Go to Step 8
81. Check the injector connections.
2. If any of the injectors are connected to an incorrect
cylinder, correct as necessary.
Was a problem found?
—Go to Step 12Go to Step 9
91. Perform the “Injector Coil/Balance Test” in Fuel
Metering System
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Go to Step 12Go to Step 10
101. Refer to Engine Cooling for cooling system
diagnosis.
2. If a problem is found, repair as necessary.
Was a problem found?
—Go to Step 12Go to Step 11
111. Remove excessive carbon buildup with a top engine
cleaner. Refer to the instructions on the top engine
cleaner can.
2. Perform the exhaust emission test.
Does the vehicle pass the test?
—System OKGo to Step 13
12Perform the exhaust emission test.
Does the vehicle pass the test?
—System OKGo to Step 13

6E–297 ENGINE DRIVEABILITY AND EMISSIONS
Mass Air Flow (MAF) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the electrical connector from the MAF
sensor.
TS23740
3. Loosen the clamps which secure the intake air duct
and the air cleaner to the MAF sensor.
4. Remove the intake air duct from the MAF sensor.
5. Remove the MAF sensor from the air cleaner.
TS23781
Installation Procedure
1. Install the MAF sensor on the air cleaner with the
clamp.2. Install the intake air duct and the clamp on the MAF
sensor.
TS23781
3. Tighten the clamps to secure the MAF sensor to the
intake air duct and the air cleaner.
4. Connect the MAF electrical connector.
5. Connect the negative battery cable.
Manifold Absolute Pressure
(MAP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the electrical connector from the MAP
sensor.
055RW005
3. Remove the bolt securing the MAP sensor to the
mounting bracket on the common chamber.

6E–300
ENGINE DRIVEABILITY AND EMISSIONS
4. Disconnect the red, white, and blue electrical
connectors at the PCM.
5. Remove the two screws in the front of the PCM.
6. Remove the one screw at the left rear of the PCM.
7. Pull the PCM straight out from the dashboard.
TS23757
Installation Procedure
1. Insert the PCM into the dashboard.
Line up the holes in front for the mounting screws.
2. Install the PCM with two screws in the front and one
screw at the left rear.
3. Plug the red, white, and blue connectors into the
appropriate sockets.
TS23757
EEPROM
General Description
The Electronically Erasable Programmable Read Only
Memory (EEPROM) is a permanent memory that is
physically soldered within the PCM. The EEPROM
contains program and calibration information that the
PCM needs to control powertrain operation.
EEPROM Programming
1. Step-up – Ensure that the following conditions have
been met:
The battery is fully charged.
The ignition is “ON.”
The Vehicle Interface Module cable connection at
the DLC is secure.
2. Program the PCM using the latest software matching
the vehicle. Refer to up-to-date Techline equipment
user’s instructions.
3. If the PCM fails to program, Refer to
UBS 98 model
year Immobilizer Workshop Manual.
Functional Check
1. Perform the On-Board Diagnostic System Check.
2. Start the engine and run for one minute.
3. Scan for DTCs using the Tech 2.
Power Steering Pressure (PSP)
Switch
General Description
The Power Steering Pressure (PSP) switch closes when
the hydraulic pressure reaches 3920
690 kPa (570
100 psi). This causes the PCM to actuate the idle air
control valve in order to prevent the additional load from
slowing down the engine. The switch opens when the
hydraulic pressure drops to 2970
560 kPa (430 80
psi).
Removal Procedure
1. Disconnect the PSP switch pigtail from the wiring
harness.
The pigtail is permanently attached to the switch.
Do not attempt to remove the wires from the
sensor.
Have a container ready to catch the power steering
fluid that leaks out of the line when the switch is
removed.

6E–302
ENGINE DRIVEABILITY AND EMISSIONS
2. Connect the TP electrical connector.
3. Install the negative battery cable.
Vehicle Speed Sensor (VSS)
Removal Procedure
CAUTION: The VSS is located on the right side of
the transfer case just ahead of the rear propeller
shaft and very close to the exhaust pipes. Be sure
that the exhaust pipes are cool enough to touch
before trying to remove the VSS. If the pipes are hot,
you could be burned.
1. Disconnect the negative battery cable.
2. Disconnect the VSS electrical connector.
TS23748
3. Remove the bolt and the clamp securing the VSS in
place.
IMPORTANT:H a v e a c o n t a i n e r r e a d y t o c a t c h a n y f l u i d
that leaks out when the VSS is removed from the transfer
case.
TS23780
4. Remove the VSS from the transfer case by wiggling it
slightly and pulling it straight out.
Inspection Procedure
1. Inspect the electrical connector for signs of corrosion
or warping. Replace the VSS if the electrical
connector is corroded or warped.
2. Inspect the VSS driven gear for chips, breaks, or worn
condition. Replace the VSS if the driven gear is
chipped, broken or worn.
3. Inspect the O-ring for wear, nicks, tears, or
looseness. Replace the O-ring if necessary.
Installation Procedure
1. Install the VSS in the transfer case with the notch for
the connector facing the rear.
2. Secure the VSS in place with the clamp and the bolt.
Tighten
Tighten the bolt to 16 Nꞏm (12 lb ft.).
TS23780
3. Connect the VSS electrical connector.
TS23748

6E–303 ENGINE DRIVEABILITY AND EMISSIONS
4. Check the transfer case oil level. Add fluid if
necessary.
5. Connect the negative battery cable.
Air Cleaner/Air Filter
Removal Procedure
1. Loosen the clamp between the air cleaner lid and the
mass air flow sensor.
2. Release the four latches securing the lid to the air
cleaner housing.
3. Remove the air cleaner lid.
TS23973
4. Remove the air filter element.
TS23794
5. Remove the retaining bolts and the air cleaner
housing from the vehicle.
130RT002
Installation Procedure
1. Install the air cleaner housing in the vehicle with the
retaining bolts.
130RT002

6E–304
ENGINE DRIVEABILITY AND EMISSIONS
2. Install the air filter element in the air cleaner housing.
TS23794
3. Install the air cleaner lid on the MAF sensor and the air
cleaner housing.
TS23973
4. Tighten the clamp and secure the four latches
between the lid and the air cleaner housing.
Idle Air Control (IAC) Valve
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the IAC electrical connector.
3. Remove the bolts and the IAC valve from the throttle
body.
NOTE: Do not clean the IAC valve by soaking it in
solvent. The valve will be damaged as a result.
TS23745
Cleaning, Inspection, and
Measurement Procedure
Clean the IAC valve O-ring sealing surface, pintle
valve seat and air passage.
– Use carburetor cleaner and a parts cleaning brush to
remove carbon deposits. Do not use a cleaner that
contains methyl ethyl ketone. This is an extremely
strong solvent and not necessary for this type of
deposit.
– Shiny spots on the pintle are normal and do not
indicate misalignment or a bent pintle shaft.
– If the air passage has heavy deposits, remove the
throttle body for complete cleaning.
TS23746
Inspect the IAC valve O-ring for cuts, cracks, or
distortion. Replace the O-ring if damaged.

6E–316
ENGINE DRIVEABILITY AND EMISSIONS
5. Remove the two bolts from the protector that secures
the common chamber.
014RW109
6. Remove the fuel pressure regulator attaching screw.
F06RW043
7. Remove the fuel pressure regulator from the fuel rail.
Disassembly Procedure
1. Remove the O-ring from the fuel pressure regulator.
2. Loosen the swivel nut.
3. Remove the fuel return line from the fuel pressure
regulator.
4. Remove the O-ring from the fuel return line.
The O-ring may be left inside the fuel pressure
regulator instead of on the fuel return line.
F06RW043
Assembly Procedure
1. Install a new O-ring on the fuel return line.
2. Install the fuel return line on the fuel pressure
regulator.
NOTE: Do not over-tighten the swivel nut on the fuel
pressure regulator. The fuel pressure regulator can be
damaged and fuel may leak if the swivel nut is
over-tightened.
3. Tighten the swivel nut.
4. Install a new O-ring on the fuel pressure regulator.