power DODGE RAM 2002 Service Repair Manual
[x] Cancel search | Manufacturer: DODGE, Model Year: 2002, Model line: RAM, Model: DODGE RAM 2002Pages: 2255, PDF Size: 62.07 MB
Page 2194 of 2255
(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P1686 No SKIM BUS Messages Received No CCD/J1850 messages received from the Smart Key
Immobilizer Module (SKIM).
P1687 No MIC BUS Message (No Cluster
BUS Message)No CCD/J1850 messages received from the Mechanical
Instrument Cluster (MIC) module.
P1688 (M) Internal Fuel Injection Pump Controller
FailureInternal problem within the fuel injection pump. Low power,
engine derated, or engine stops.
P1689 (M) No Communication Between ECM and
Injection Pump ModuleData link circuit failure between ECM and fuel injection
pump. Low power, engine derated, or engine stops.
P1690 (M) Fuel Injection Pump CKP Sensor Does
Not Agree With ECM CKP SensorProblem in fuel sync signal. Possible injection pump timing
problem. Low power, engine derated, or engine stops.
P1691 Fuel Injection Pump Controller
Calibration ErrorInternal fuel injection pump failure. Low power, engine
derated, or engine stops.
P1692 DTC Set In ECM A9Companion DTC9was set in both the ECM and PCM.
P1693 (M) DTC Detected in Companion Module A fault has been generated in the companion engine control
module.
P1693 (M) DTC Detected in PCM/ECM or DTC
Detected in ECMA9Companion DTC9was set in both the ECM and PCM.
P1694 Fault In Companion Module No CCD/J1850 messages received from the powertrain
control module-Aisin transmission
P1694 (M) No BUS (CCD) Messages received
from ECMBus communication failure to PCM.
P1695 No CCD/J1850 Message From Body
Control ModuleNo CCD/J1850 messages received from the body control
module.
P1696 PCM Failure EEPROM Write Denied Unsuccessful attempt to write to an EEPROM location by the
control module.
P1697 PCM Failure SRI Mile Not Stored Unsuccessful attempt to update Service Reminder Indicator
(SRI or EMR) mileage in the control module EEPROM.
P1698 No CCD/J1850 Message From TCM No CCD/J1850 messages received from the electronic
transmission control module (EATX) or the Aisin transmission
controller.
P1698 No CCD Messages received from
PCMBus communication failure to PCM. A9Companion DTC9was
set in both the ECM and PCM.
P1699 No Climate Control Bus Messages
P1719 Skip Shift Solenoid Circuit An open or shorted condition detected in the transmission
2-3 gear lock-out solenoid control circuit.
P1740 TCC or OD Sol Perf A rationality error has been detected in either the TCC
solenoid or overdrive solenoid systems.
P1740 (M) TCC OR O/D Solenoid Performance Problem detected in transmission convertor clutch and/or
overdrive circuits (diesel engine with 4-speed auto. trans.
only).
P1756 (M) GOV Press Not Equal to Target @
15-20 PSIThe requested pressure and the actual pressure are not
within a tolerance band for the Governor Control System
which is used to regulate governor pressure to control shifts
for 1st, 2nd, and 3rd gear. (Mid Pressure Malfunction)
BR/BEEMISSIONS CONTROL 25 - 15
EMISSIONS CONTROL (Continued)
Page 2195 of 2255
(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P1756 (M) Governor Pressure Not Equal to Target
@ 15-20 PSIGovernor sensor input not between 10 and 25 psi when
requested (4-speed auto. trans. only).
P1757 GOV Press Not Equal to Target @
15-20 PSIThe requested pressure and the actual pressure are not
within a tolerance band for the Governor Control System
which is used to regulate governor pressure to control shifts
for 1st, 2nd, and 3rd gear (Zero Pressure Malfunction)
P1757 (M) Governor Pressure Above 3 PSI In
Gear With 0 MPHGovernor pressure greater than 3 psi when requested to be
0 psi (4-speed auto. trans. only).
P1762 (M) Gov Press Sen Offset Volts Too Lo or
HighThe Governor Pressure Sensor input is greater than a
calibration limit or is less than a calibration limit for 3
consecutive park/neutral calibrations.
P1762 (M) Governor Press Sen Offset Volts Too
Low or HighSensor input greater or less than calibration for 3
consecutive Neutral/Park occurrences (4-speed auto. trans.
only).
P1763 Governor Pressure Sensor Volts Too
HiThe Governor Pressure Sensor input is above an acceptable
voltage level.
P1763 (M) Governor Pressure Sensor Volts Too
HIVoltage greater than 4.89 volts (4-speed auto. trans. only).
P1764 (M) Governor Pressure Sensor Volts Too
LowThe Governor Pressure Sensor input is below an acceptable
voltage level.
P1764 (M) Governor Pressure Sensor Volts Too
LowVoltage less than .10 volts (4-speed auto. trans. only).
P1765 (M) Trans 12 Volt Supply Relay CTRL
CircuitAn open or shorted condition is detected in the Transmission
Relay control circuit. This relay supplies power to the TCC
P1765 (M) Trans 12 Volt Supply Relay Ctrl Circuit Current state of solenoid output port is different than
expected (4-speed auto. trans. only).
P1830 Clutch Override Relay Circuit Problem detected in clutch pedal switch override relay circuit.
P1899 (M) P/N Switch Stuck in Park or in Gear Incorrect input state detected for the Park/Neutral switch.
P1899 (M) P/N Switch Stuck in Park or in Gear Incorrect input state detected for the Park/Neutral switch (3
or 4-speed auto. trans. only).
25 - 16 EMISSIONS CONTROLBR/BE
EMISSIONS CONTROL (Continued)
Page 2196 of 2255
DESCRIPTION - TASK MANAGER
The PCM is responsible for efficiently coordinating
the operation of all the emissions-related compo-
nents. The PCM is also responsible for determining if
the diagnostic systems are operating properly. The
software designed to carry out these responsibilities
is call the 'Task Manager'.
DESCRIPTION - MONITORED SYSTEMS
There are new electronic circuit monitors that
check fuel, emission, engine and ignition perfor-
mance. These monitors use information from various
sensor circuits to indicate the overall operation of the
fuel, engine, ignition and emission systems and thus
the emissions performance of the vehicle.
The fuel, engine, ignition and emission systems
monitors do not indicate a specific component prob-
lem. They do indicate that there is an implied prob-
lem within one of the systems and that a specific
problem must be diagnosed.
If any of these monitors detect a problem affecting
vehicle emissions, the Malfunction Indicator Lamp
(MIL) will be illuminated. These monitors generate
Diagnostic Trouble Codes that can be displayed with
the MIL or a scan tool.
The following is a list of the system monitors:
²Misfire Monitor
²Fuel System Monitor
²Oxygen Sensor Monitor
²Oxygen Sensor Heater Monitor
²Catalyst Monitor
²Leak Detection Pump Monitor (if equipped)
All these system monitors require two consecutive
trips with the malfunction present to set a fault.
Refer to the appropriate Powertrain Diagnos-
tics Procedures manual for diagnostic proce-
dures.
The following is an operation and description of
each system monitor :
OXYGEN SENSOR (O2S) MONITOR
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperature 300É to 350ÉC (572É to 662ÉF), the
sensor generates a voltage that is inversely propor-
tional to the amount of oxygen in the exhaust. The
information obtained by the sensor is used to calcu-
late the fuel injector pulse width. This maintains a
14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio,
the catalyst works best to remove hydrocarbons (HC),
carbon monoxide (CO) and nitrogen oxide (NOx) from
the exhaust.
The O2S is also the main sensing element for the
Catalyst and Fuel Monitors.The O2S can fail in any or all of the following
manners:
²slow response rate
²reduced output voltage
²dynamic shift
²shorted or open circuits
Response rate is the time required for the sensor to
switch from lean to rich once it is exposed to a richer
than optimum A/F mixture or vice versa. As the sen-
sor starts malfunctioning, it could take longer to
detect the changes in the oxygen content of the
exhaust gas.
The output voltage of the O2S ranges from 0 to 1
volt. A good sensor can easily generate any output
voltage in this range as it is exposed to different con-
centrations of oxygen. To detect a shift in the A/F
mixture (lean or rich), the output voltage has to
change beyond a threshold value. A malfunctioning
sensor could have difficulty changing beyond the
threshold value.
OXYGEN SENSOR HEATER MONITOR
If there is an oxygen sensor (O2S) shorted to voltage
DTC, as well as a O2S heater DTC, the O2S fault
MUST be repaired first. Before checking the O2S fault,
verify that the heater circuit is operating correctly.
Effective control of exhaust emissions is achieved
by an oxygen feedback system. The most important
element of the feedback system is the O2S. The O2S
is located in the exhaust path. Once it reaches oper-
ating temperature 300É to 350ÉC (572 É to 662ÉF), the
sensor generates a voltage that is inversely propor-
tional to the amount of oxygen in the exhaust. The
information obtained by the sensor is used to calcu-
late the fuel injector pulse width. This maintains a
14.7 to 1 Air Fuel (A/F) ratio. At this mixture ratio,
the catalyst works best to remove hydrocarbons (HC),
carbon monoxide (CO) and nitrogen oxide (NOx) from
the exhaust.
The voltage readings taken from the O2S sensor
are very temperature sensitive. The readings are not
accurate below 300ÉC. Heating of the O2S sensor is
done to allow the engine controller to shift to closed
loop control as soon as possible. The heating element
used to heat the O2S sensor must be tested to ensure
that it is heating the sensor properly.
The O2S sensor circuit is monitored for a drop in
voltage. The sensor output is used to test the heater
by isolating the effect of the heater element on the
O2S sensor output voltage from the other effects.
LEAK DETECTION PUMP MONITOR (IF EQUIPPED)
The leak detection assembly incorporates two pri-
mary functions: it must detect a leak in the evapora-
tive system and seal the evaporative system so the
leak detection test can be run.
BR/BEEMISSIONS CONTROL 25 - 17
EMISSIONS CONTROL (Continued)
Page 2197 of 2255
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three port
solenoid is briefly energized. This initializes the
pump by drawing air into the pump cavity and also
closes the vent seal. During non test conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that prevents the diaphragm
assembly from reaching full travel. After the brief
initialization period, the solenoid is de-energized
allowing atmospheric pressure to enter the pump
cavity, thus permitting the spring to drive the dia-
phragm which forces air out of the pump cavity and
into the vent system. When the solenoid is energized
and de energized, the cycle is repeated creating flow
in typical diaphragm pump fashion. The pump is con-
trolled in 2 modes:
Pump Mode: The pump is cycled at a fixed rate to
achieve a rapid pressure build in order to shorten the
overall test length.
Test Mode: The solenoid is energized with a fixed
duration pulse. Subsequent fixed pulses occur when
the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5º H20.
The cycle rate of pump strokes is quite rapid as the
system begins to pump up to this pressure. As the
pressure increases, the cycle rate starts to drop off. If
there is no leak in the system, the pump would even-
tually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .040º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases due
to the flow through the purge system, the leak check
portion of the diagnostic is complete.
The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicated
by a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the Air Fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S sensor output. The programmed
memory acts as a self calibration tool that the engine
controller uses to compensate for variations in engine
specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the
actual fuel-air ratio with the O2S sensor (short term)
and multiplying that with the program long-term
(adaptive) memory and comparing that to the limit,
it can be determined whether it will pass an emis-
sions test. If a malfunction occurs such that the PCM
cannot maintain the optimum A/F ratio, then the
MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide.
Normal vehicle miles or engine misfire can cause a
catalyst to decay. This can increase vehicle emissions
and deteriorate engine performance, driveability and
fuel economy.
25 - 18 EMISSIONS CONTROLBR/BE
EMISSIONS CONTROL (Continued)
Page 2199 of 2255
DESCRIPTION - COMPONENT MONITORS -
DIESEL ENGINES
There are several electrical components that will
affect vehicle emissions if they malfunction. If one of
these components is malfunctioning, a Diagnostic
Trouble Code (DTC) will be set by either the Power-
train Control Module (PCM) or the Engine Control
Module (ECM). The Malfunction Indicator Lamp
(MIL) will then be illuminated when the engine is
running.
These electrically operated components have input
(rationality) and output (functionality) checks. A
check is done by one or more components to check
the operation of another component.
Example:The Intake Manifold Air Temperature
(IAT) sensor is used to monitor intake manifold air
temperature over a period of time after a cold start.
If the temperature has not risen to a certain specifi-
cation during a specified time, a Diagnostic Trouble
Code (DTC) will be set for a problem in the manifold
air heater system.
All open/short circuit checks, or any component
that has an associated limp-in will set a DTC and
trigger the MIL after 1 trip with the malfunction
present. Components without an associated limp-in
will take two trips to illuminate the MIL.
OPERATION
OPERATION - GAS ENGINES
The Powertrain Control Module (PCM) monitors
many different circuits in the fuel injection, ignition,
emission and engine systems. If the PCM senses a
problem with a monitored circuit often enough to
indicate an actual problem, it stores a Diagnostic
Trouble Code (DTC) in the PCM's memory. If the
problem is repaired or ceases to exist, the PCM can-
cels the code after 40 warm-up cycles. Diagnostic
trouble codes that affect vehicle emissions illuminate
the Malfunction Indicator Lamp (MIL). The MIL is
displayed as an engine icon (graphic) on the instru-
ment panel. Refer to Malfunction Indicator Lamp in
this section.
Certain criteria must be met before the PCM
stores a DTC in memory. The criteria may be a spe-
cific range of engine RPM, engine temperature,
and/or input voltage to the PCM.
The PCM might not store a DTC for a monitored
circuit even though a malfunction has occurred. This
may happen because one of the DTC criteria for the
circuit has not been met.For example, assume the
diagnostic trouble code criteria requires the PCM to
monitor the circuit only when the engine operates
between 750 and 2000 RPM. Suppose the sensor's
output circuit shorts to ground when engine operatesabove 2400 RPM (resulting in 0 volt input to the
PCM). Because the condition happens at an engine
speed above the maximum threshold (2000 rpm), the
PCM will not store a DTC.
There are several operating conditions for which
the PCM monitors and sets DTC's. Refer to Moni-
tored Systems, Components, and Non-Monitored Cir-
cuits in this section.
Technicians must retrieve stored DTC's by connect-
ing the DRB scan tool (or an equivalent scan tool) to
the 16±way data link connector (Fig. 3).
NOTE: Various diagnostic procedures may actually
cause a diagnostic monitor to set a DTC. For
instance, pulling a spark plug wire to perform a
spark test may set the misfire code. When a repair
is completed and verified, connect the DRB scan
tool to the 16±way data link connector to erase all
DTC's and extinguish the MIL.
OPERATION - DIESEL
The PCM and ECM monitor many different cir-
cuits in the powertrain system. If the ECM or PCM
senses a problem with a monitored circuit often
enough to indicate an actual problem, it stores a
Diagnostic Trouble Code (DTC) in the ECM's or
PCM's memory. With certain DTC's, if the problem is
repaired or ceases to exist, the ECM or PCM cancels
the code after 40 warm-up cycles. Certain other
DTC's may be cancelled after 1 or 2 good ªtripsº.
Refer to Trip Definition. DTC's that affect vehicle
emissions illuminate the Malfunction Indicator Lamp
(MIL). The MIL is displayed as an engine icon
(graphic) on the instrument panel. Refer to Malfunc-
tion Indicator Lamp.
Fig. 3 16-WAY DATA LINK CONNECTOR
1 - DATA LINK CONNECTOR
25 - 20 EMISSIONS CONTROLBR/BE
EMISSIONS CONTROL (Continued)
Page 2205 of 2255
AIR INJECTION
TABLE OF CONTENTS
page page
AIR INJECTION
DESCRIPTION - AIR INJECTION SYSTEM....26
OPERATION - AIR INJECTION SYSTEM......28
SPECIFICATIONS
TORQUE - AIR INJECTION SYSTEM.......29
AIR INJECTION PUMP
DESCRIPTION.........................29
OPERATION...........................29
DIAGNOSIS AND TESTING - AIR INJECTION
PUMP..............................29
REMOVAL.............................30INSTALLATION.........................30
AIR PUMP FILTER
REMOVAL.............................30
INSTALLATION.........................30
ONE WAY CHECK VALVE
DESCRIPTION.........................31
OPERATION...........................31
DIAGNOSIS AND TESTING - ONE-WAY
CHECK VALVE........................31
REMOVAL.............................31
INSTALLATION.........................31
AIR INJECTION
DESCRIPTION - AIR INJECTION SYSTEM
The air injection system (Fig. 1), (Fig. 2) or (Fig. 3)
is used on 5.9L V-8 and 8.0L V-10 heavy duty cycle
(HDC) gas powered engines only. The air injection
system consists of:
²A belt-driven air injection (AIR) pump²Two air pressure relief valves
²Rubber connecting air injection hoses with
clamps
²Metal connecting air tubes
²Two one-way check valves
²A replaceable injection pump air filter (8.0L V-10
engine only)
25 - 26 AIR INJECTIONBR/BE
Page 2211 of 2255
EVAPORATIVE EMISSIONS
TABLE OF CONTENTS
page page
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAP SYSTEM............32
SPECIFICATIONS
TORQUE - EVAP SYSTEM..............32
CCV HOSE
DESCRIPTION - 8.0L....................33
OPERATION - 8.0L......................33
EVAP/PURGE SOLENOID
DESCRIPTION.........................33
OPERATION...........................33
REMOVAL.............................33
INSTALLATION.........................34
FUEL FILLER CAP
DESCRIPTION.........................34
OPERATION...........................34
REMOVAL/INSTALLATION................34
LEAK DETECTION PUMP
DESCRIPTION.........................34OPERATION...........................34
REMOVAL.............................34
INSTALLATION.........................34
P C V VA LV E
DESCRIPTION - V-8 ENGINES.............35
OPERATION - V-8 ENGINES...............35
DIAGNOSIS AND TESTING - PCV VALVE -
5.9L................................36
VACUUM LINES
DESCRIPTION.........................37
VAPOR CANISTER
DESCRIPTION.........................37
OPERATION...........................37
REMOVAL.............................38
INSTALLATION.........................38
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAP SYSTEM
The evaporation control system prevents the emis-
sion of fuel tank vapors into the atmosphere. When
fuel evaporates in the fuel tank, the vapors pass
through vent hoses or tubes into the two charcoal
filled evaporative canisters. The canisters tempo-
rarily hold the vapors. The Powertrain Control Mod-
ule (PCM) allows intake manifold vacuum to draw
vapors into the combustion chambers during certain
operating conditions.
All 5.9L/8.0L gasoline powered engines use a duty
cycle purge system. The PCM controls vapor flow byoperating the duty cycle EVAP purge solenoid. Refer
to Duty Cycle EVAP Canister Purge Solenoid for
additional information.
When equipped with certain emissions packages, a
Leak Detection Pump (LDP) will be used as part of
the evaporative system. This pump is used as part of
OBD II requirements. Refer to Leak Detection Pump
in this group for additional information.
NOTE: The hoses used in this system are specially
manufactured. If replacement becomes necessary, it
is important to use only fuel resistant hose.
SPECIFICATIONS
TORQUE - EVAP SYSTEM
DESCRIPTION N´m Ft. Lbs. In. Lbs.
EVAP Canister Mounting Nuts 9 80
Leak Detection Pump Mounting Screws 1 11
Leak Detection Pump Filter Mounting Bolt 7 65
25 - 32 EVAPORATIVE EMISSIONSBR/BE
Page 2212 of 2255
CCV HOSE
DESCRIPTION - 8.0L
The 8.0L V-10 engine is equipped with a Crankcase
Ventilation (CCV) system. The CCV system performs
the same function as a conventional PCV system, but
does not use a vacuum controlled valve (PCV valve).
A molded vacuum tube connects manifold vacuum
to the top of the right cylinder head (valve) cover.
The vacuum tube connects to a fixed orifice fitting
(Fig. 1) of a calibrated size 2.6 mm (0.10 inches).
OPERATION - 8.0L
A molded vacuum tube connects manifold vacuum to
the top of the right cylinder head (valve) cover. The vac-
uum tube connects to a fixed orifice fitting (Fig. 1) of a
calibrated size 2.6 mm (0.10 inches). The fitting meters
the amount of crankcase vapors drawn out of the
engine.The fixed orifice fitting is grey in color.A
similar fitting (but does not contain a fixed orifice) is
used on the left cylinder head (valve) cover. This fitting
is black in color. Do not interchange these two fittings.
When the engine is operating, fresh air enters the
engine and mixes with crankcase vapors. Manifold
vacuum draws the vapor/air mixture through the
fixed orifice and into the intake manifold. The vapors
are then consumed during engine combustion.
EVAP/PURGE SOLENOID
DESCRIPTION
All 5.9L/8.0L gasoline powered engines use a duty
cycle EVAP canister purge solenoid. The solenoid reg-ulates the rate of vapor flow from the EVAP canister
to the throttle body.
OPERATION
The Powertrain Control Module (PCM) operates
the solenoid.
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged. The
PCM de-energizes the solenoid during open loop oper-
ation.
The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM ener-
gizes and de-energizes the solenoid 5 or 10 times per
second, depending upon operating conditions. The
PCM varies the vapor flow rate by changing solenoid
pulse width. Pulse width is the amount of time the
solenoid energizes. The PCM adjusts solenoid pulse
width based on engine operating condition.
REMOVAL
The duty cycle solenoid is attached to a bracket
mounted to the right inner fender (Fig. 2).
(1) Disconnect electrical wiring connector at sole-
noid (Fig. 2).
(2) Disconnect vacuum harness at solenoid.
(3) Remove solenoid from support bracket.
Fig. 1 Fixed Orifice FittingÐ8.0L V-10 EngineÐ
Typical
1 - VACUUM TUBE
2 - FIXED ORIFICE FITTING
3 - COIL PACKS
4 - ORIFICE FITTING HOSE CONNECTIONS
Fig. 2 Duty Cycle EVAP Canister Purge Solenoid
Location
1 - RIGHT-FRONT FENDER
2 - LDP FILTER
3 - DUTY CYCLE SOLENOID
4 - ELEC. CONNEC.
5 - LEAK DETECTION PUMP (LDP) (IF EQUIPPED)
6 - LDP ELEC. CONNEC.
BR/BEEVAPORATIVE EMISSIONS 25 - 33
Page 2214 of 2255
(2) Install LDP filter to mounting bracket. Tighten
bolt to 7 N´m (65 in. lbs.) torque.
(3) Carefully install vapor/vacuum lines to LDP,
and install hose to LDP filter.The vapor/vacuum
lines and hoses must be firmly connected.
Check the vapor/vacuum lines at the LDP, LDP
filter and EVAP canister purge solenoid for
damage or leaks. If a leak is present, a Diagnos-
tic Trouble Code (DTC) may be set.
(4) Connect electrical connector to LDP.
PCV VALVE
DESCRIPTION - V-8 ENGINES
All 5.9L V-8 gas powered engines are equipped
with a closed crankcase ventilation system and a pos-
itive crankcase ventilation (PCV) valve. The 8.0L
V-10 engine is not equipped with a PCV valve. Refer
to Crankcase Ventilation SystemÐ8.0L V-10 Engine
for information.
This system consists of a PCV valve mounted on
the cylinder head (valve) cover with a hose extending
from the valve to the intake manifold (Fig. 3).
Another hose connects the opposite cylinder head
(valve) cover to the air cleaner housing to provide a
source of clean air for the system. A separate crank-
case breather/filter is not used.
OPERATION - V-8 ENGINES
The PCV system operates by engine intake mani-
fold vacuum (Fig. 4). Filtered air is routed into the
crankcase through the air cleaner hose. The metered
air, along with crankcase vapors, are drawn through
the PCV valve and into a passage in the intake man-
ifold. The PCV system manages crankcase pressure
and meters blow by gases to the intake system,
reducing engine sludge formation.
The PCV valve contains a spring loaded plunger.
This plunger meters the amount of crankcase vapors
routed into the combustion chamber based on intake
manifold vacuum.
When the engine is not operating or during an
engine pop-back, the spring forces the plunger back
against the seat (Fig. 5). This will prevent vapors
from flowing through the valve.
Fig. 3 Typical PCV Valve/Hose (Non±California
Shown)
1 - P C V VA LV E
2 - PCV VALVE HOSE CONNECTIONS
Fig. 4 Typical Closed Crankcase Ventilation System
1 - THROTTLE BODY
2 - AIR CLEANER
3 - AIR INTAKE
4 - P C V VA LV E
5 - COMBUSTION CHAMBER
6 - BLOW-BY GASES
7 - CRANKCASE BREATHER/FILTER
Fig. 5 Engine Off or Engine Pop-BackÐNo Vapor
Flow
BR/BEEVAPORATIVE EMISSIONS 25 - 35
LEAK DETECTION PUMP (Continued)
Page 2216 of 2255
(4) Turn engine off and remove PCV valve from
valve cover. The valve should rattle when shaken
(Fig. 10).
(5) Replace the PCV valve and retest the system if
it does not operate as described in the preceding
tests.Do not attempt to clean the old PCV valve.
(6) If the paper is not held against the opening in
valve cover after new valve is installed, the PCV
valve hose may be restricted and must be replaced.
The passage in the intake manifold must also be
checked and cleaned.
(7) To clean the intake manifold fitting, turn a 1/4
inch drill (by hand) through the fitting to dislodge
any solid particles. Blow out the fitting with shop air.
If necessary, use a smaller drill to avoid removing
any metal from the fitting.
VACUUM LINES
DESCRIPTION
A vacuum schematic for emission related items can
be found on the VECI label. Refer to Vehicle Emis-
sion Control Information (VECI) Label for label loca-
tion.
VAPOR CANISTER
DESCRIPTION
Two, maintenance free, EVAP canisters are used
with all 5.9L/8.0L gasoline powered engines. Both
canisters are mounted to a bracket located below
rear of vehicle cab on outside of right frame rail (Fig.
11).
OPERATION
Two, maintenance free, EVAP canisters are used
with all 5.9L/8.0L gasoline powered engines.The
EVAP canisters are filled with granules of an acti-
vated carbon mixture. Fuel vapors entering the
EVAP canisters are absorbed by the charcoal gran-
ules.
Fuel tank pressure vents into the EVAP canisters.
Fuel vapors are temporarily held in the canisters
until they can be drawn into the intake manifold.
The duty cycle EVAP canister purge solenoid allows
the EVAP canisters to be purged at predetermined
times and at certain engine operating conditions.
Fig. 10 Shake PCV
1 - PCV VALVE GROMMET
2 - P C V VA LV E
3 - PCV VALVE MUST RATTLE WHEN SHAKEN
Fig. 11 Location of EVAP Canisters
1 - MOUNTING NUTS
2 - FRAME RAIL (RIGHT)
3 - FRONT EVAP CANISTER
4 - REAR EVAP CANISTER
BR/BEEVAPORATIVE EMISSIONS 25 - 37
PCV VALVE (Continued)