1999 DODGE RAM sensor

(8) - One used on vehicles with light-duty emissions. Two used on 

vehicles with heavy-duty emissions. 

(
9) - Used on vehicles with heavy-duty emissions. 

(
10 ) - Two catalytic converters are required. 

(
11 ) - Four sensors used on vehicles with medium-duty emissions. 

Two sensors used on vehicles with heavy-duty emissions. 










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ABBREVIATIONS
ABBREVIATION DEFINITIONS








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Abbreviation Definition
AIH ................................... Air Intake Heaters
AIH-TS ............................ AIH Temperature Sensor
AP ............................. Air Pump Injection System
AP-CKV .................................... AP Check Valve
AP-RV .................................... AP Relief Valve
BP/EGR ........................... Backpressure EGR System
BP/EGR-BPT ................ BP/EGR Backpressure Transducer
CCV ................................ Crankcase Ventilation
CEC ......................... Computerized Engine Controls
CNG ............................... Compressed Natural Gas
EFI ............................ Electronic Fuel Injection
EGR-CKV .................................. EGR Check Valve
EVAP ............................. Fuel Evaporative System
EVAP-CVV ........................ EVAP Canister Vent Valve
EVAP-LDP ........................ EVAP Leak Detection Pump
EVAP-LDPF ................ EVAP Leak Detection Pump Filter
EVAP-PRRV ............ EVAP Pressure Relief Rollover Valve
EVAP-PSOL ............................ EVAP Purge Solenoid
EVAP-VC .............................. EVAP Vapor Canister
EVAP-VV ........................... EVAP Ventilation Valve
FR ................................... Fillpipe Restrictor
HO2S ................................ Heated Oxygen Sensor
MIL .......................... Malfunction Indicator Light
PCV ....................... Positive Crankcase Ventilation
SFI .................. Sequential Multiport Fuel Injection
SPK ....................................... Spark Controls
SPK-CC ........................... SPK Computer Controlled
TWC ........................ Three-Way Catalytic Converter









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These 3 orifices are opened and closed by electric solenoids. The
solenoids are, in turn, controlled by the Electronic Control Module
(ECM). When a solenoid is energized, the armature with attached shaft
and swivel pintle is lifted, opening the orifice. See Fig. 11.
The ECM uses inputs from the Coolant Temperature Sensor
(CTS), Throttle Position Sensor (TPS) and Mass Airflow (MAF) senso\
rs
to control the EGR orifices to make 7 different combinations for
precise EGR flow control. At idle, the EGR valve allows a very small
amount of exhaust gas to enter the intake manifold. This EGR valve
normally operates above idle speed during warm engine operation.
Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed
switches, etc., (if applicable) are not by-passed or modified. Ensure
vacuum hose(s) to EGR valve is not plugged. Ensure electrical
connector to EGR valve is not disconnected.
Fig. 11: Typical Digital EGR Valve
Courtesy of General Motors Corp.
Integrated Electronic EGR Valve
This type functions similar to a ported EGR valve with a

remote vacuum regulator. The internal solenoid is normally open, which
causes the vacuum signal to be vented off to the atmosphere when EGR
is not controlled by the Electronic Control Module (ECM). The solenoid\
valve opens and closes the vacuum signal, controlling the amount of
vacuum applied to the diaphragm. See Fig. 12.
The electronic EGR valve contains a voltage regulator, which
converts ECM signal and regulates current to the solenoid. The ECM
controls EGR flow with a pulse width modulated signal based on
airflow, TPS and RPM. This system also contains a pintle position
sensor, which works similarly to a TPS sensor. As EGR flow is
increased, the sensor output increases.
Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed
switches, etc., (if applicable) are not by-passed or modified. Ensure
electrical connector to EGR valve is not disconnected.
Fig. 12: Cutaway View Of Typical Integrated Electronic EGR Valve
Courtesy of General Motors Corp.
SPARK CONTROLS (SPK)

Spark control systems are designed to ensure the air/fuel
mixture is ignited at the best possible moment to provide optimum
efficiency and power and cleaner emissions.
Ensure vacuum hoses to the distributor, carburetor, spark
delay valves, thermal vacuum switches, etc., are in place and routed
properly. On Computerized Engine Controls (CEC), check for presence of\
required sensors (O2, MAP, CTS, TPS, etc.). Ensure they have not been
tampered with or modified.
Check for visible modification or replacement of the feedback
carburetor, fuel injection unit or injector(s) with a non-feedback
carburetor or fuel injection system. Check for modified emission-
related components unacceptable for use on pollution-controlled
vehicles.
AIR INJECTION SYSTEM (AIS)
Air Pump Injection System (AP)
The air pump is a belt-driven vane type pump, mounted to
engine in combination with other accessories. The air pump itself
consists of the pump housing, an inner air cavity, a rotor and a vane
assembly. As the vanes turn in the housing, filtered air is drawn in
through the intake port and pushed out through the exhaust port. See
Fig. 13 .
Check for missing or disconnected belt, check valve(s),
diverter valve(s), air distribution manifolds, etc. Check air
injection system for proper hose routing.
Fig. 13: Typical Air Pump Injection System
Courtesy of General Motors Corp.
Pulsed Secondary Air Injection (PAIR) System
PAIR eliminates the need for an air pump and most of the
associated hardware. Most systems consists of air delivery pipe(s),
pulse valve(s) and check valve(s). The check valve prevents exhaust
gases from entering the air injection system. See Fig. 14.
Ensure required check valve(s), diverter valve(s), air
distribution manifolds, etc., are present. Check air injection system
for proper hose routing.

Fig. 14: Typical Pulsed Secondary Air Injection System
Courtesy of General Motors Corp.
OXYGEN SENSOR (O2)
The O2 sensor is mounted in the exhaust system where it
monitors oxygen content of exhaust gases. Some vehicles may use 2 O2
sensors. The O2 sensor produces a voltage signal which is proportional
to exhaust gas oxygen concentration (0-3%) compared to outside oxygen
(20-21%). This voltage signal is low (about .1 volt) when a lean
mixture is present and high (1.0 volt) when a rich mixture is present.\
As ECM compensates for a lean or rich condition, this voltage
signal constantly fluctuates between high and low, crossing a
reference voltage supplied by the ECM on the O2 signal line. This is
referred to as cross counts. A problem in the O2 sensor circuit should
set a related trouble code.
COMPUTERIZED ENGINE CONTROLS (CEC)
The CEC system monitors and controls a variety of
engine/vehicle functions. The CEC system is primarily an emission
control system designed to maintain a 14.7:1 air/fuel ratio under most
operating conditions. When the ideal air/fuel ratio is maintained, the
catalytic converter can control oxides of nitrogen (NOx), hydrocarbon
(HC) and carbon monoxide (CO) emissions.
The CEC system consists of the following sub-systems:
Electronic Control Module (ECM), input devices (sensors and switches)\
and output signals.

FITTINGS. Remove air cleaner, throttle body, drive belts, generator,
fan and fan pulley. Remove lower fan shroud.
CAUTION: When removing engine, DO NOT lift engine by intake manifold.
5) Remove intake manifold. See INTAKE MANIFOLD. Raise and
support vehicle. Remove starter. Remove exhaust pipe and heat shields.
Disconnect transmission shift linkage. Remove crank sensor.
6) On A/T models, remove transmission inspection cover. Mark
torque converter-to-flexplate position for installation reference.
Remove torque converter-to-flexplate bolts. On M/T models, disconnect
clutch release mechanism at clutch housing.
7) Attach engine hoist to cylinder heads (at intake manifold
flanges). On all models, support transmission using a floor jack.
Remove transmission or clutch housing-to-cylinder block bolts. Remove
engine mount bolts. Remove engine out front of vehicle.
Installation
To install, reverse removal procedure. Tighten bolts/nuts to
specification. See TORQUE SPECIFICATIONS table. On A/T models, ensure
reference marks on torque converter and flexplate are aligned.
Evacuate and charge A/C system.
Removal ( Dakota 2WD, Durango 2WD, Grand Cherokee & Ram
Pickup)
1) Release fuel pressure. See FUEL PRESSURE RELEASE.
Disconnect and remove battery. On all except Pickup, scribe hood
hinges for installation reference and remove hood.
2) On all models, drain cooling system. Disconnect coolant
hoses. Remove radiator, fan and shroud. Discharge A/C system (if
equipped) using approved refrigerant recovery/recycling equipment.
Disconnect A/C lines, and plug openings. On Pickup, remove upper core
support, transmission cooler and A/C condenser. On all models, remove
belt, air cleaner, vacuum lines, distributor cap and wiring.
3) Disconnect necessary electrical wiring. Disconnect fuel
lines. See FUEL LINE DISCONNECT FITTINGS. Remove throttle body and
linkage. Remove intake manifold. Remove starter, generator, charcoal
canister and horns. Disconnect power steering hoses (if equipped).
Raise and support vehicle. Drain oil. Disconnect exhaust pipe at
exhaust manifold.
4) On A/T models, remove transmission housing inspection
plate. Mark torque converter-to-flexplate position for installation
reference. Remove torque converter-to-flexplate bolts. Remove bracket
for transmission cooler lines.
NOTE: It may be necessary to remove manual transmission if
transmission cannot be supported using floor jack.
5) On M/T models, disconnect clutch release mechanism at
clutch housing. On all models, support transmission using a floor
jack. Remove transmission or clutch housing-to-cylinder block bolts.
Install engine lifting fixture, and attach chain.
CAUTION: When removing engine, DO NOT lift engine by intake manifold.
6) On Ram Pickup and Grand Cherokee, remove front engine
mount bolts. Remove engine from vehicle. On Dakota 2WD and Durango 2WD
models, remove front engine mount through-bolts. See Fig. 3. Remove
engine from vehicle.
Installation
To install, reverse removal procedure. Tighten bolts/nuts to
specification. See TORQUE SPECIFICATIONS table. On A/T models, ensure

components, reverse removal procedure.
Removal (Dakota 4WD & Durango 4WD)
1) Disconnect negative battery cable. Remove oil dipstick.
Drain engine oil. Remove exhaust pipe crossover and lower transmission
cover.
2) Remove front drive axle for access to oil pan. For front
drive axle removal, loosen wheel lug nuts. Remove cotter pin, lock nut
and spring washer. Loosen axle shaft nut with vehicle on floor and
brakes applied. Raise and support vehicle.
CAUTION: DO NOT pull on rubber boot during axle shaft removal. Pull on
outer CV joint only.
3) Remove wheels and skid plate. Remove axle shaft nut.
Remove axle shaft-to-differential flange bolts at front drive axle.
Support axle shaft, and separate axle splines from wheel hub by
pulling inward at outer CV joint.
4) Remove remaining axle shaft. Mark front drive shaft and
transfer case yoke for installation reference. Remove front drive
shaft from transfer case. Disconnect vacuum hoses from shift motor and
electrical connections at shift indicator switch.
5) Support front drive axle using a floor jack. Remove front
drive axle and shift motor bolts. Lower floor jack, and remove front
drive axle with drive shaft. Remove transmission lower cover. Remove
bolts, oil pan and gasket.
Installation
1) To install, reverse removal procedure. Before installing
oil pan, apply RTV sealant where front cover contacts cylinder block,
oil pan side gaskets meet end seals and end seals contact cylinder
block. See Fig. 14.
2) To facilitate oil pan installation, fabricate 4 alignment
dowels from 1 1/2" x 5/16" bolts. See Fig. 15. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table.
3) To install remaining components, reverse removal
procedure. When installing front drive axle, loosely install all bolts
before tightening to specification. Tighten axle shaft nut to
specification with vehicle on ground. See TORQUE SPECIFICATIONS table.
Ensure reference marks on transfer case yoke and front drive shaft are
aligned.
Removal (Ram Pickup & Ram Van/Wagon - 3.9L)
1) Disconnect negative battery cable. Remove oil dipstick. On
Ram Van/Wagon, remove engine cover. On all models, remove air cleaner
and engine controller. Raise and support vehicle. Drain engine oil.
2) Remove left engine-to-transmission strut. Loosen exhaust
pipe support bracket. Disconnect exhaust pipe. On Ram Pickup, remove
oil pan and gasket.
3) On Ram Van/Wagon, remove starter, transmission dust
shield, oxygen sensor and air injection tube. On all models, remove
right engine mount nut. Loosen, but DO NOT remove, left engine mount
nut.
4) Support right side of engine using jackstand. Remove
transmission mount through-bolt, and support transmission using
jackstand. Raise engine and transmission enough for oil pan removal.
Remove bolts, oil pan and gasket.
Installation
1) To install, reverse removal procedure. Before installing
oil pan, apply RTV sealant where front cover contacts cylinder block,
oil pan side gaskets meet end seals and end seals contact cylinder
block. See Fig. 14.

2) To facilitate oil pan installation, fabricate 4 alignment
dowels from 1 1/2" x 5/16" bolts. See Fig. 15. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table. To install remaining
components, reverse removal procedure. Tighten bolts to specification.
See TORQUE SPECIFICATIONS table. To install remaining components,
reverse removal procedure.
Removal (Ram Pickup & Ram Van/Wagon - 5.2L & 5.9L)
Disconnect negative battery cable. Remove oil dipstick. Raise
and support vehicle. Drain engine oil. Remove exhaust pipe. Remove
left engine-to-transmission strut. Remove bolts, oil pan and gasket.
Installation
1) To install, reverse removal procedure. Before installing
oil pan, apply RTV sealant where front cover contacts cylinder block,
oil pan side gaskets meet end seals and end seals contact cylinder
block. See Fig. 14.
2) To facilitate oil pan installation, fabricate 4 alignment
dowels from 1 1/2" x 5/16" bolts. See Fig. 15. Tighten bolts to
specification. See TORQUE SPECIFICATIONS table. To install remaining
components, reverse removal procedure.
Removal (Grand Cherokee)
Disconnect negative battery cable. Remove oil dipstick. Raise
and support vehicle. Drain engine oil. Disconnect O2 sensor. Remove
exhaust pipe and starter. Remove left engine-to-transmission strut.
Disconnect oil level sensor (if equipped). Remove bolts, oil pan and
gasket. DO NOT damage oil level sensor.
Installation
1) To install, reverse removal procedure. Before installing
oil pan, apply RTV sealant where front cover contacts cylinder block,
oil pan side gaskets meet end seals and end seals contact cylinder
block. See Fig. 14.
2) To facilitate oil pan installation on all models,
fabricate 4 alignment dowels from 1 1/2" x 5/16" bolts. See Fig. 15.
Tighten bolts to specification. See TORQUE SPECIFICATIONS table. To
install remaining components, reverse removal procedure.
Fig. 14: Applying Sealant On Oil Pan Sealing Surfaces
Courtesy of Chrysler Corp.