is enabled to run another test during that trip. When
the test fails 6 times, the counter increments to 3, a
malfunction is entered, and a Freeze Frame is stored,
the code is matured and the MIL is illuminated. If
the first test passes, no further testing is conducted
during that trip.
The MIL is extinguished after three consecutive
good trips. The good trip criteria for the catalyst
monitor is more stringent than the failure criteria. In
order to pass the test and increment one good trip,
the downstream sensor switch rate must be less than
45% of the upstream rate. The failure percentages
are 59% respectively.
Enabling ConditionsÐThe following conditions
must typically be met before the PCM runs the cat-
alyst monitor. Specific times for each parameter may
be different from engine to engine.
²Accumulated drive time
²Enable time
²Ambient air temperature
²Barometric pressure
²Catalyst warm-up counter
²Engine coolant temperature
²Vehicle speed
²MAP
²RPM
²Engine in closed loop
²Fuel level
Pending ConditionsÐ
²Misfire DTC
²Front Oxygen Sensor Response
²Front Oxygen Sensor Heater Monitor
²Front Oxygen Sensor Electrical
²Rear Oxygen Sensor Rationality (middle check)
²Rear Oxygen Sensor Heater Monitor
²Rear Oxygen Sensor Electrical
²Fuel System Monitor
²All TPS faults
²All MAP faults
²All ECT sensor faults
²Purge flow solenoid functionality
²Purge flow solenoid electrical
²All PCM self test faults
²All CMP and CKP sensor faults
²All injector and ignition electrical faults
²Idle Air Control (IAC) motor functionality
²Vehicle Speed Sensor
²Brake switch (auto trans only)
²Intake air temperature
ConflictÐThe catalyst monitor does not run if any
of the following are conditions are present:
²EGR Monitor in progress (if equipped)
²Fuel system rich intrusive test in progress
²EVAP Monitor in progress
²Time since start is less than 60 seconds
²Low fuel level-less than 15 %²Low ambient air temperature
²Ethanel content learn is takeng place and the
ethenal used once flag is set
SuspendÐThe Task Manager does not mature a
catalyst fault if any of the following are present:
²Oxygen Sensor Monitor, Priority 1
²Oxygen Sensor Heater, Priority 1
²EGR Monitor, Priority 1 (if equipped)
²EVAP Monitor, Priority 1
²Fuel System Monitor, Priority 2
²Misfire Monitor, Priority 2
OPERATION - NON-MONITORED CIRCUITS
The PCM does not monitor all circuits, systems
and conditions that could have malfunctions causing
driveability problems. However, problems with these
systems may cause the PCM to store diagnostic trou-
ble codes for other systems or components. For exam-
ple, a fuel pressure problem will not register a fault
directly, but could cause a rich/lean condition or mis-
fire. This could cause the PCM to store an oxygen
sensor or misfire diagnostic trouble code.
The major non-monitored circuits are listed below
along with examples of failures modes that do not
directly cause the PCM to set a DTC, but for a sys-
tem that is monitored.
FUEL PRESSURE
The fuel pressure regulator controls fuel system
pressure. The PCM cannot detect a clogged fuel
pump inlet filter, clogged in-line fuel filter, or a
pinched fuel supply or return line. However, these
could result in a rich or lean condition causing the
PCM to store an oxygen sensor, fuel system, or mis-
fire diagnostic trouble code.
SECONDARY IGNITION CIRCUIT
The PCM cannot detect an inoperative ignition coil,
fouled or worn spark plugs, ignition cross firing, or
open spark plug cables. The misfire will however,
increase the oxygen content in the exhaust, deceiving
the PCM in to thinking the fuel system is too lean.
Also misfire detection.
CYLINDER COMPRESSION
The PCM cannot detect uneven, low, or high engine
cylinder compression. Low compression lowers O2
content in the exhaust. Leading to fuel system, oxy-
gen sensor, or misfire detection fault.
EXHAUST SYSTEM
The PCM cannot detect a plugged, restricted or
leaking exhaust system. It may set a EGR (if
equipped) or Fuel system or O2S fault.
RSEMISSIONS CONTROL25-5
EMISSIONS CONTROL (Continued)
ProCarManuals.com
Alternate Good Trips are used in place of Global
Good Trips for Comprehensive Components and
Major Monitors. If the Task Manager cannot run a
Global Good Trip because a component fault is stop-
ping the monitor from running, it will attempt to
count an Alternate Good Trip.
The Task Manager counts an Alternate Good Trip
for Comprehensive components when the following
conditions are met:
²Two minutes of engine run time, idle or driving
²No other faults occur
The Task Manager counts an Alternate Good Trip
for a Major Monitor when the monitor runs and
passes. Only the Major Monitor that failed needs to
pass to count an Alternate Good Trip.
Warm-Up Cycles
Once the MIL has been extinguished by the Good
Trip Counter, the PCM automatically switches to a
Warm-Up Cycle Counter that can be viewed on the
DRBIIIt. Warm-Up Cycles are used to erase DTCs
and Freeze Frames. Forty Warm-Up cycles must
occur in order for the PCM to self-erase a DTC and
Freeze Frame. A Warm-Up Cycle is defined as fol-
lows:
²Engine coolant temperature must start below
and rise above 160É F
²Engine coolant temperature must rise by 40É F
²No further faults occur
Freeze Frame Data Storage
Once a failure occurs, the Task Manager records
several engine operating conditions and stores it in a
Freeze Frame. The Freeze Frame is considered one
frame of information taken by an on-board data
recorder. When a fault occurs, the PCM stores the
input data from various sensors so that technicians
can determine under what vehicle operating condi-
tions the failure occurred.
The data stored in Freeze Frame is usually
recorded when a system fails the first time for two
trip faults. Freeze Frame data will only be overwrit-
ten by a different fault with a higher priority.
CAUTION: Erasing DTCs, either with the DRBIIIT;or
by disconnecting the battery, also clears all Freeze
Frame data.
Similar Conditions Window
The Similar Conditions Window displays informa-
tion about engine operation during a monitor. Abso-
lute MAP (engine load) and Engine RPM are stored
in this window when a failure occurs. There are two
different Similar conditions Windows: Fuel System
and Misfire.
FUEL SYSTEM²Fuel System Similar Conditions WindowÐ
An indicator that 'Absolute MAP When Fuel Sys Fail'
and 'RPM When Fuel Sys Failed' are all in the same
range when the failure occurred. Indicated by switch-
ing from 'NO' to 'YES'.
²Absolute MAP When Fuel Sys FailÐ The
stored MAP reading at the time of failure. Informs
the user at what engine load the failure occurred.
²Absolute MAPÐ A live reading of engine load
to aid the user in accessing the Similar Conditions
Window.
²RPM When Fuel Sys FailÐ The stored RPM
reading at the time of failure. Informs the user at
what engine RPM the failure occurred.
²Engine RPMÐ A live reading of engine RPM
to aid the user in accessing the Similar Conditions
Window.
²Adaptive Memory FactorÐ The PCM utilizes
both Short Term Compensation and Long Term Adap-
tive to calculate the Adaptive Memory Factor for
total fuel correction.
²Upstream O2S VoltsÐ A live reading of the
Oxygen Sensor to indicate its performance. For
example, stuck lean, stuck rich, etc.
²SCW Time in Window (Similar Conditions
Window Time in Window)Ð A timer used by the
PCM that indicates that, after all Similar Conditions
have been met, if there has been enough good engine
running time in the SCW without failure detected.
This timer is used to increment a Good Trip.
²Fuel System Good Trip CounterÐATrip
Counter used to turn OFF the MIL for Fuel System
DTCs. To increment a Fuel System Good Trip, the
engine must be in the Similar Conditions Window,
Adaptive Memory Factor must be less than cali-
brated threshold and the Adaptive Memory Factor
must stay below that threshold for a calibrated
amount of time.
²Test Done This TripÐ Indicates that the
monitor has already been run and completed during
the current trip.
MISFIRE
²Same Misfire Warm-Up StateÐ Indicates if
the misfire occurred when the engine was warmed up
(above 160É F).
²In Similar Misfire WindowÐ An indicator
that 'Absolute MAP When Misfire Occurred' and
'RPM When Misfire Occurred' are all in the same
range when the failure occurred. Indicated by switch-
ing from 'NO' to 'YES'.
²Absolute MAP When Misfire OccurredÐ
The stored MAP reading at the time of failure.
Informs the user at what engine load the failure
occurred.
25 - 26 ON-BOARD DIAGNOSTICSRS
TASK MANAGER (Continued)
ProCarManuals.com
EXHAUST GAS RECIRCULATION
TABLE OF CONTENTS
page page
EXHAUST GAS RECIRCULATION
DESCRIPTION..........................3
OPERATION............................3
VA LV E
DESCRIPTION..........................3
OPERATION............................3REMOVAL.............................4
INSTALLATION..........................4
VALVE COOLER
DESCRIPTION..........................4
REMOVAL.............................4
INSTALLATION..........................5
EXHAUST GAS
RECIRCULATION
DESCRIPTION
The EGR system reduces oxides of nitrogen (NOx)
in the engine exhaust. This is accomplished by allow-
ing a predetermined amount of hot exhaust gas to
recirculate and dilute the incoming fuel/air mixture.
A malfunctioning EGR system can cause engine
stumble, sags, or hesitation, rough idle, engine stall-
ing and poor driveability.
OPERATION
The system consists of:
²An EGR valve assembly. The valve is located on
the rear of the engine above the exhaust manfiold.
²An EGR solenoid.The EGR solenoid controls the
ªon timeº of the EGR valve.
²The ECM operates the EGR solenoid. The ECM
is located inside the vehicle under the instrument
panel.
²An EGR tube connects a passage in the EGR
valve to the rear of the exhaust manifold.
²The vacuum pump supplies vacuum for the EGR
solenoid and the EGR valve. This pump also supplies
vacuum for operation of the power brake boosterb
and the heating and air conditioning system. The
pump is located internally in the front of the engine
block and is driven by the crankshaft gear.²Vacuum lines and hoses connect the various
components.
When the ECM supplies a variable ground signal
to the EGR solenoid, EGR system operation starts to
occur. The ECM will monitor and determine when to
supply and remove this variable ground signal. This
will depend on inputs from the engine coolant tem-
perature, throttle position and engine speed sensors.
When the variable ground signal is supplied to the
EGR solenoid, vacuum from the vacuum pump will
be allowed to pass through the EGR solenoid and on
to the EGR valve with a connecting hose.
Exhaust gas recirculation will begin in this order
when:
²The ECM determines that EGR system opera-
tion is necessary.
²The engine is running to operate the vacuum
pump.
²A variable ground signal is supplied to the EGR
solenoid.
²Variable vacuum passes through the EGR sole-
noid to the EGR valve.
²The inlet seat (poppet valve) at the bottom of
the EGR valve opens to dilute and recirculate
exhaust gas back into the intake manifold.
The EGR system will be shut down by the ECM
after 60 seconds of continuous engine idling to
improve idle quality.
RGEXHAUST GAS RECIRCULATION25a-3
ProCarManuals.com
VA LV E
DESCRIPTION
The EGR system consists of (Fig. 1):
²EGR valve
²EGR tube
²Vacuum hoses
²EGR cooler
²EGR solenoid
OPERATION
The engines use Exhaust Gas Recirculation (EGR)
systems. The EGR system reduces oxides of nitrogen
(NOx) in engine exhaust and helps prevent detona-
tion (engine knock). Under normal operating condi-
tions, engine cylinder temperature can reach more
than 3000ÉF. Formation of NOx increases proportion-
ally with combustion temperature. To reduce the
emission of these oxides, the cylinder temperature
must be lowered. The system allows a predetermined
amount of hot exhaust gas to recirculate and dilute
the incoming air/fuel mixture. The diluted air/fuel
mixture reduces peak flame temperature during com-
bustion.
REMOVAL
(1) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(2) Remove front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL).
(3) Disconnect EGR valve vacuum line.
(4) Remove EGR cooler to EGR valve retaining
bolts (Fig. 1).
(5) Remove EGR valve retaining nuts (Fig. 1) and
EGR valve.
INSTALLATION
(1) Clean gasket mating surfaces.
(2) Install EGR valve (Fig. 1). Torque nuts to
32.4N´m.
(3) Connect EGR cooler to EGR valve (Fig. 1).
Torque bolts to 32.4N´m
(4) Install front wiper unit (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(5) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
Fig. 1 EGR COMPONENTS
1 - HOSE CLAMP
2 - COOLANT HOSE
3 - HOSE CLAMP
4 - EGR VALVE RETAINING NUT
5 - E G R VA LV E
6 - COOLANT HOSE
7 - EGR VALVE GASKET
8 - EGR VALVE RETAINING STUDS
9 - EGR COOLER RETAINING BOLT
10 - HOSE CLAMP
11 - HOSE CLAMP
12 - EGR COOLER
13 - EGR COOLER TO EGR VALVE RETAINING BOLT
14 - TURBOCHARGER BRACKET
15 - TURBOCHARGER BRACKET RETAINING BOLT
16 - TURBOCHARGER DOWNPIPE
17 - TURBOCHARGER DOWNPIPE RETAINING NUT
18 - DOWNPIPE GASKET
19 - DOWNPIPE STUD
25a - 4 EXHAUST GAS RECIRCULATIONRG
ProCarManuals.com
VALVE COOLER
DESCRIPTION
The EGR valve on this engine uses a cooler to cool
the exhaust gases before the returned to the intake
manifold (Fig. 2). The EGR cooler attaches to the
EGR valve and is cooled with engine coolant.
REMOVAL
(1) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(2) Partially drain cooling system (Refer to 7 -
COOLING/ENGINE/COOLANT - STANDARD PRO-
CEDURE).
(3) Remove front wiper unit (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL).
(4) Disconnect coolant supply and return lines at
EGR cooler (Fig. 2).
(5) Remove EGR cooler to exhaust manifold retain-
ing bolt (Fig. 2).
(6) Remove EGR cooler to EGR valve retaining
bolts (Fig. 2) and remove cooler.
INSTALLATION
(1) Clean gasket sealing surfaces.
(2) Connect EGR valve cooler and new gasket to
EGR valve (Fig. 2). Torque bolts to 32.4N´m.
(3) Install EGR valve cooler to exhaust manifold
attaching bolt (Fig. 2). Torque bolt to 32.4N´m.
(4) Connect EGR cooler coolant supply and return
hoses to cooler (Fig. 2).
(5) Install front wiper unit (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION).
(6) Refill cooling system (Refer to 7 - COOLING/
ENGINE/COOLANT - STANDARD PROCEDURE).
(7) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
Fig. 2 EGR COMPONENTS
1 - HOSE CLAMP
2 - COOLANT HOSE
3 - HOSE CLAMP
4 - EGR VALVE RETAINING NUT
5 - E G R VA LV E
6 - COOLANT HOSE
7 - EGR VALVE GASKET
8 - EGR VALVE RETAINING STUDS
9 - EGR COOLER RETAINING BOLT
10 - HOSE CLAMP
11 - HOSE CLAMP
12 - EGR COOLER
13 - EGR COOLER TO EGR VALVE RETAINING BOLT
14 - TURBOCHARGER BRACKET
15 - TURBOCHARGER BRACKET RETAINING BOLT
16 - TURBOCHARGER DOWNPIPE
17 - TURBOCHARGER DOWNPIPE RETAINING NUT
18 - DOWNPIPE GASKET
19 - DOWNPIPE STUD
RGEXHAUST GAS RECIRCULATION25a-5
ProCarManuals.com
ENGINE CONTROL MODULE (ECM) - DRBIIITCODES
Generic Scan Tool Code DRB IIITScan Tool Display
P0070 Ambient Air Temperature Circuit Signal Voltage Too High
Ambient Air Temperature Circuit Signal Voltage Too Low
P0100 Mass Air Flow Sensor Plausibility
Mass Air Flow Sensor Plausibility Positive Area
Mass Air Flow Sensor Signal Voltage Too High
Mass Air Flow Sensor Signal Voltage Too Low
Mass Air Flow Sensor Supply Voltage Too High Or Low
P0105 Barometric Pressure Circuit Signal Voltage To High
Barometric Pressure Circuit Signal Voltage To Low
P0110 Intake Air Temperature Sensor Circuit Signal Too High
Intake Air Temperature Sensor Circuit Signal Too Low
P0115 Engine Coolant Temperature Sensor Circuit Engine Is Cold Too Long
Engine Coolant Temperature Sensor Circuit Voltage To Low
Engine Coolant Temperature Sensor Circuit Voltage To High
P0190 Fuel Pressure Sensor Circuit MALF Signal Voltage Too High
Fuel Pressure Sensor Circuit MALF Signal Voltage Too Low
P0195 Oil Temperature Sensor Circuit MALF Signal Voltage Too High
Oil Temperature Sensor Circuit MALF Signal Voltage Too Low
P0201 Cylinder 1 Injector Circuit Current Decrease
Cylinder 1 Injector Circuit Load Drop
Cylinder 1 Injector Circuit Overcurrent High Side
Cylinder 1 Injector Circuit Overcurrent Low Side
P0202 Cylinder 2 Injector Circuit Current Decrease
Cylinder 2 Injector Circuit Load Drop
Cylinder 2 Injector Circuit Overcurrent High Side
Cylinder 2 Injector Circuit Overcurrent Low Side
P0203 Cylinder 3 Injector Circuit Current Decrease
Cylinder 3 Injector Circuit Load Drop
Cylinder 3 Injector Circuit Overcurrent High Side
Cylinder 3 Injector Circuit Overcurrent Low Side
P0204 Cylinder 4 Injector Circuit Current Decrease
Cylinder 4 Injector Circuit Load Drop
Cylinder 4 Injector Circuit Overcurrent High Side
Cylinder 4 Injector Circuit Overcurrent Low Side
P0235 Boost Pressure Sensor Plausibility
Boost Pressure Sensor Signal Voltage Too Low
Boost Pressure Sensor Signal Voltage Too High
RGON-BOARD DIAGNOSTICS25a-7
ON-BOARD DIAGNOSTICS (Continued)
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