1998 OPEL FRONTERA sensor

6E–95 ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor (KS) System Check
(Engine Knock, Poor Performance, or Poor Economy)
D06RW035
Circuit Description
The knock sensor (KS) sends an AC voltage signal to the
powertrain control module (PCM). As the KS detects
engine knock, the signal to the PCM changes in amplitude
and frequency. The PCM retards timing if the engine
speed is over 900 RPM.
Diagnostic Aids
If the KS system checks OK, but detonation is the
complaint, refer to
Diagnosis, Detonation/Spark Knock.
Test Description
The numbers below refer to the step numbers on the
Diagnostic Chart.
9. The change in signal speed depends on how hard
the tapping is done. Normally there is about 1.5 to
10 mV at PCM pin A2 with the engine off. Loud
tapping should be able to make the reading jump to
20-25 mV AC.

6E–96
ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor (KS) System Check
(Engine Knock, Poor Performance, or Poor Economy)
StepActionVa l u e ( s )Ye sNo
1Is DTC P0325 or P0327 set?
—
Go to DTC
P0325 or
DTC P0327
Go to Step 2
2Run the engine at 1500 RPM.
Is there an internal engine knock?
—Go to Step 3Go to Step 4
3Repair the mechanical problem.
Is the action complete?
—Verify repair—
41. Install Tech 2.
2. Turn the ignition “ON.”
3. Cycle through the list until “Knock Retard” is
displayed.
Is knock retard at the specified value?
0Go to Step 6Go to Step 7
5Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
UBS 98model year Immobilizer
Workshop Manual.
Is the action complete?—Verify repair—
61. Start the engine.
2. Monitor the knock retard display on Tech 2 while
changing the throttle setting to place different loads
on the engine.
Is knock retard at the specified value? (Turn the ignition
“OFF.”)
0Go to Step 9Go to Step 7
71. At the rear of the engine, behind the rear fuel
injector on the lift side, disconnect the 2-wire knock
sensor harness connector.
2. Attach the positive lead of DVM to B+.
3. On the m ain harness side of the connector, use th e
negative lead of the DVM to probe the connector pin
that is connected to the black wire.
Dose the DVM indicate the specified value?
(Reconnect the knock sensor harness.)
B+Go to Step 9Go to Step 8
8Repair the open black wire ground for the shield which
prevents stray electromagnetic pulses from affecting
the knock signal.
Is the action complete?
—Verify repair—
91. Reconnect the wire harness.
2. Set a DVM to AC voltage.
3. With the DVM, backprobe the PCM connector at
A2.
4. Tap the engine lift brackprobe with a socket
extension.
Did the DVM show an increase in AC voltage while
tapping on the lift bracket?
—System OKGo to Step 10
10Replace the knock sensor.
Is the action complete?
—Verify repair—

6E–97 ENGINE DRIVEABILITY AND EMISSIONS
Exhaust Gas Recirculation (EGR) System Check
D06RW106
Circuit Description
A properly operation exhaust gas recirculation (EGR)
system will directly affect the air/fuel requirements of the
engine. Since the exhaust gas introduced into the air/fuel
mixture is an inert gas (contains very little or no oxygen),
less fuel is required to maintain a correct air/fuel ratio.
Introducing exhaust gas into the combustion chamber
lowers combustion temperatures and reduces the
formation of oxides of nitrogen (NOx) in the exhaust gas.
Lower combustion temperatures also prevent detonation.
If the EGR pintle were to stay closed, the inert exhaust
gas would be replaced with air and the air/fuel mixture
would be leaner. The powertrain control module (PCM)
would compensate for the lean condition by adding fuel,
resulting in higher long term fuel trim values.
Diagnostic Aids
The EGR valve chart is a check of the EGR system. An
EGR pintle constantly in the closed position could cause
detonation and high emissions of NOx. It could also result
in high long term fuel trim values in the open throttle cell,
but not in the closed throttle cell. An EGR pintle
constantly in the open position would cause a rough idle.
Also, an EGR mounted incorrectly (rotated 180
) could
cause rough idle. Check for the following items:
EGR passages – Check for restricted or blocked EGR
passages.
Manifold absolute pressure sensor – A manifold
absolute pressure sensor may shift in calibration
enough to affect fuel delivery. Refer to
Manifold
Absolute Pressure Output Check.

6E–99 ENGINE DRIVEABILITY AND EMISSIONS
Manifold Absolute Pressure (MAP) Output Check
D06RW102
Circuit Description
The manifold absolute pressure (MAP) sensor measures
the changes in the intake MAP which result from engine
load (intake manifold vacuum) and engine speed
changes; and converts these into a voltage output. The
powertrain control module (PCM) sends a 5-volt
reference voltage to the MAP sensor. As the MAP
changes, the output voltage of the sensor also changes.
By monitoring the the sensor output voltage, the PCM
knows the MAP. A lower pressure (low voltage) output
voltage will be about 1-2 volts at idle. Higher pressure
(high voltage) output voltage will be about 4-4.8 volts at
wide open throttle. The MAP sensor is also used, under
certain conditions, to measure barometric pressure,
allowing the PCM to make adjustments for different
altitudes. The PCM uses the MAP sensor to diagnose
proper operation of the EGR system, in addition to other
functions.
Test Description
IMPORTANT:Be sure to used the same diagnostic test
equipment for all measurements.
The number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Applying 34 kPa (10 Hg) vacuum to the MAP sensor
should cause the voltage to be 1.5-2.1 volts less
than the voltage at step 1. Upon applying vacuum
to the sensor, the change in voltage should be
instantaneous. A slow voltage change indicates a
faulty sensor.
3. Check the vacuum hose to the sensor for leaking or
restriction, Be sure that no other vacuum devices
are connected to the MAP hose.
IMPORTANT:Make sure the electrical connector
remains securely fastened.
4. Disconnect the sensor from the bracket. Twist the
sensor with your hand to check for an intermittent
connection. Output changes greater than 0.10 volt
indicate a bad sensor.

6E–100
ENGINE DRIVEABILITY AND EMISSIONS
Manifold Absolute Pressure (MAP) Output Check
StepActionVa l u e ( s )Ye sNo
11. Turn the ignition “OFF”and leave it “OFF” for 15
seconds.
2. Ignition “ON.” Don’t crank engine.
3. Tech 2 should indicate a manifold absolute pressure
(MAP) sensor voltage.
4. Compare this scan reading to scan reading of a
known good vehicle obtained using the exact same
procedure as in Steps 1-4.
Is the voltage reading the same +/–0.40 volt?
—Go to Step 2Go to Step 5
21. Disconnect the vacuum hose at the MAP sensor
and plug the hose.
2. Connect a hand vacuum pump to the MAP sensor.
3. Start the engine.
4. Apply 34 kPa (10 Hg) of vacuum and note the
voltage change.
Is the voltage change 1.5-2.1 volts less than Step 1?
—Go to Step 3Go to Step 4
3No trouble found. Check the sensor cover for leakage
or restriction.
Does the hose supply vacuum to the MAP sensor only?
—Go to Step 5Go to Step 4
4Repair the material to block.
Is the action complete?
—Verify repair—
5Check the sensor connection.
Is the sensor connection good?
—Go to Step 6Go to Step 7
6Replace the sensor. Refer to On-Vehicle Service, MAP
Sensor.
Is the action complete?—Verify repair—
7Repair the poor connection.
Is the action complete?
—Verify repair—

6E–104
ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0101 MAF System Performance
D06RW103
Circuit Description
The mass air flow (MAF) sensor measures the amount of
air which passes through it into the engine during a given
time. The powertrain control module (PCM) uses the
mass air flow information to monitor engine operating
conditions for fuel delivery calculations. A large quantity
of air entering the engine indicates an acceleration or high
load situation, while a small quantity or air indicates
deceleration or idle.
The MAF sensor produces a frequency signal which can
be monitored using a Tech 2. DTC P0101 will be set if the
signal from the MAF sensor does not match a predicted
value based on throttle position and engine RPM.
Conditions for Setting the DTC
The engine is running.
No TP sensor or MAP sensor DTCs are set.
The throttle is steady, TP angle doesn’t change by
more than 1%.
System voltage is between 11.5 volts and 16 volts.
Calculated air flow is between 25 g/second and 40
g/second.
Above conditions present for at least 1 second.
MAF signal frequency indicates an airflow significantly
higher or lower than a predicted value based on throttle
position and engine RPM for a total of 12.5 seconds
over a 25-second period of time.
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 calculates an airflow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.
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 P0101 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.
Diagnostic Aids
An intermittent may be caused by the following:
Poor connections.
Mis-routed harness.
Rubbed through wire insulation.
Broken wire inside the insulation.
Refer to Intermittents under service category Symptoms.
Any un-metered air may cause this DTC to set. Check for
the following:
The duct work at the MAF sensor for leaks.
An engine vacuum leak.
The PCV system for vacuum leaks.
An incorrect PCV valve.

6E–105 ENGINE DRIVEABILITY AND EMISSIONS
The engine oil dip stick not fully seated.
The engine oil fill cap loose or missing.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. The MAF system performance or “rationality”
diagnostic uses the MAP sensor signal along with
other input to calculate an expected airflow rate that
is then compared to the actual measured airflow
from the MAF sensor. The first few steps of this
table verify that the MAP sensor is working properly.
6. Using Freeze Frame and/or Failure Records data
may aid in locating an intermittent condition. If the
DTC cannot be duplicated, the information included
in the Freeze Frame and/or Failure Records data
can be useful in determining how many miles since
the DTC set. The Fail Counter and Pass Counter
can also be used to determine how many ignition
cycles the diagnostic reported a pass and/or a fail.
Operate the vehicle within the same Freeze Frame
conditions (RPM, load, vehicle speed , temperature,
etc.) that were noted. This will isolate when the
DTC failed.For any test that requires back probing the PCM or
component harness connectors, use the Connector
Test Adapter Kit J 35616-A. Using this kit will
prevent any damage to the harness connector
terminals.
7. Any un-metered air may cause this DTC to set.
Check the PVC system for vacuum leaks. Also
inspect the dip stick for being pulled out. Check the
oil fill cap for being loose.
8. Verifies the signal circuit from the MAF sensor
electrical connector to the PCM.
9. Verifies whether a ground and B+ circuit is available.
10. Checks a signal circuit for an open.
11. Checks for a signal circuit shorted to B+.
DTC P0101 – MAF System Performance
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. Using a Tech 2, select “MAP” from the Engine 1
Data List.
Is the value displayed greater than the value shown?
85 kPaGo to Step 3Go toStep 13
31. Remove the MAP sensor from the intake manifold
but leave the electrical harness connected.
2. Connect a hand operated vacuum pump to the MAP
sensor.
3. Observe the MAP display while slowly applying
vacuum up to 20” Hg as indicated on the pump
gauge.
Each 1” of vacuum applied should result in a 3 to 4 kPa
drop in the MAP sensor value on the Tech 2 and the
value should change smoothly with each increase in
vacuum.
Did the MAP value change smoothly through the entire
range of the test without any erratic readings?
—Go to Step 13Go to Step 4
4With 20” Hg vacuum applied to the MAP sensor, is the
MAF sensor reading the same or less than the value
shown?
34 kPaGo to Step 5Go to Step 13
5Disconnect the vacuum source from the MAP sensor.
Does the MAP sensor reading return to its original
value?
—Go to Step 6Go to Step 13

6E–106
ENGINE DRIVEABILITY AND EMISSIONS
DTC P0101 – MAF System Performance
StepNo Ye s Va l u e ( s ) Action
61. Ignition “ON,” engine “OFF.”
2. Review the Freeze Frame and/or Failure Records
data for this DTC and note parameters.
3. Ignition “OFF” for 15 seconds.
4. Start the engine and operate the vehicle within the
conditions required for this diagnostic to run, and as
close to the conditions recorded in Freeze Frame
/Failure Records possible. (Special operating
conditions that need to be met before the PCM will
run this diagnostic (where applicable) are listed in
“Conditions for Setting the DTC”).
5. Using the Tech 2, select “DTC,” then enter the DTC
number which was set.
Does the Tech 2 indicate that this diagnostic failed this
ignition?
—Go to Step 7
Refer to
Diagnostic
Aids
71. Check for the following conditions:
Objects blocking the MAF sensor inlet screen;
Intake manifold vacuum leaks;
Vacuum leaks at throttle body;
Vacuum leaks EGR value flange and pipes.
Crankcase ventilation valve faulty, missing, or
incorrectly installed.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo toStep 8
81. Ignition “OFF.”
2. Disconnect the MAF sensor connector.
3. Ignition “ON,” engine “OFF.”
4. Using DVM 5-8840-0285-0, measure voltage
between the MAF sensor signal circuit and chassis
ground.
Is the voltage near the specified value?
5 VGo to Step 9Go toStep 10
9Connect a test light (5-8840-0607-0) between the MAF
sensor ignition feed and ground circuits at the MAF
sensor harness connector.
Is the test light “ON?”
—Go to Step 13Go toStep 12
10Is the voltage less than the specified value?4.5 VGo to Step 13Go toStep 11
111. Ignition “OFF,” disconnect the PCM.
2. Ignition “ON,” engine “OFF.”
3. Measure voltage between the MAF signal circuit
and ground.
Does the voltage measure near the specified value?
0 VGo to Step 13Go toStep 12
12Connect a test light (5-8840-0607-0) between the MAF
sensor ignition feed circuit and chassis ground.
Is the test light “ON?”
—Go to Step 13Go toStep 7
131. Check for a poor connection at the MAF sensor.
2. If a poor connection is found, replace faulty
terminal(s). Refer to
Repair Procedures in
Electrical Diagnosis (8A Cell 5).
Was a poor connection found?—Verify repairSolved