6E–54
ENGINE DRIVEABILITY AND EMISSIONS
A/C Clutch Control Circuit Diagnosis
D06RW085
Circuit Description
When air conditioning and blower fan are selected, and if
the system has a sufficient refrigerant charge, a 12-volt
signal is supplied to the A/C request input of the
powertrain control module (PCM). The A/C request
signal may be temporarily canceled during system
operation by the electronic thermostat in the evaporator
case. The electronic thermostat may intermittently
remove the control circuit ground for the A/C thermostat
relay to prevent the evaporator from forming ice. When
the A/C request signal is received by the PCM, the PCM
supplies a ground from the compressor clutch relay if the
engine operating conditions are within acceptable
ranges. With the A/C compressor relay energized,
voltage is supplied to the compressor clutch coil.
The PCM will enable the compressor clutch to engage
whenever A/C has been selected with the engine running,
unless any of the following conditions are present:
The throttle is greater than 90%.
The ignition voltage is below 10.5 volts.
The engine speed is greater than 4500 RPM for 5
seconds or 5400 RPM.
The engine coolant temperature (ECT) is greater than
125
C (257 F).
The intake air temperature (IAT) is less than 5C
(41
F).
The power steering pressure switch signals a cramped
position.
Diagnostic Aids
To diagnose an the intermittent fault, check for the
following conditions:
Poor connection at the PCM–Inspect connections for
backed-out terminals, improper mating, broken locks,
improperly formed or damaged terminals, and poor
terminal-to-wire connection.
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–301 ENGINE DRIVEABILITY AND EMISSIONS
2. Remove the PSP switch from the power steering line.
Plug the line to prevent excessive loss of fluid and
possible contamination of the power steering
system.
TS23760
Installation Procedure
1. Install the PSP switch in the power steering line.
TS23760
2. Connect the PSP switch pigtail to the wiring harness.
3. Check the power steering fluid level. Refer to
Power
Steering
.
4. Start the engine. Watch the PSP switch for signs of
fluid leakage.
Throttle Position (TP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the TPS electrical connector.3. Remove the bolts and the TP sensor from the throttle
body.
TS23747
NOTE: Do not clean the TP sensor by soaking it in
solvent. The sensor will be damaged as a result.
Function Check
Use a Tech 2 to check the TP sensor output voltage at
closed throttle.
The voltage should be under 0.85 volt.
If the reading is greater than 0.85 volt, check the
throttle shaft to see if it is binding. Check that the
throttle cable is properly adjusted, also. Refer to
Throttle Cable Adjustment.
If the throttle shaft is not binding and the throttle cable
is properly adjusted, install a new TP sensor.
Installation Procedure
1. Install the TP sensor on the throttle body with the
bolts.
TS23747
6E–339 ENGINE DRIVEABILITY AND EMISSIONS
0005
PCM Components
The PCM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency. The PCM
monitors numerous engine and vehicle functions via
electronic sensors such as the throttle position (TP)
sensor, heated oxygen sensor (HO2S), and vehicle
speed sensor (VSS). The PCM also controls certain
engine operations through the following:
Fuel injector control
Ignition control module
Knock sensor
Automatic transmission shift functions
Cruise control
A/C clutch control
PCM Voltage Description
The PCM supplies a buffered voltage to various switches
and sensors. It can do this because resistance in the
PCM is so high in value that a test light may not illuminate
when connected to the circuit. An ordinary shop
voltmeter may not give an accurate reading because the
voltmeter input impedance is too low. Use a 10-megohm
input impedance digital voltmeter (such as J 39200) to
assure accurate voltage readings.
The input/output devices in the PCM include
analog-to-digital converters, signal buffers, counters,
and special drivers. The PCM controls most components
with electronic switches which complete a ground circuit
when turned “ON.” These switches are arranged in
groups of 4 and 7, called either a surface-mounted quad
driver module (QDM), which can independently control up
to 4 output terminals, or QDMs which can independently
control up to 7 outputs. Not all outputs are always used.
PCM Input/Outputs
Inputs – Operating Conditions Read
Air Conditioning “ON” or “OFF”
Engine Coolant Temperature
Crankshaft Position
Exhaust Oxygen Content
Electronic Ignition
Manifold Absolute Pressure
Battery Voltage
Throttle Position
Vehicle Speed
Fuel Pump Voltage
Power Steering Pressure
Intake Air Temperature
Mass Air Flow
Engine Knock
Camshaft Position
Outputs – Systems Controlled
Exhaust Gas Recirculation (EGR)
Ignition Control
Fuel Control
Idle Air Control
Electric Fuel Pump
Air Conditioning
Diagnostics
– Malfunction Indicator Lamp (Service Engine Soon
lamp)
– Data Link Connector (DLC)
– Data Output
Transmission Control Module
Alternator Gain Control
PCM Service Precautions
The PCM is designed to withstand normal current draws
associated with vehicle operation. Avoid overloading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the PCM’s circuits unless
instructed to do so. These circuits should only be tested
Tech-2. The PCM should remain connected to the PCM
or to a recommended breakout box.
Reprogramming The PCM
The Trooper allow reprogramming of the PCM without
removing it from the vehicle . This provides a flexible and
cost-effective method of making changes in software
calibrations.
The service programming system (SPS) will not allow
incorrect software programming or incorrect calibration
changes.
Refer to the UBS 98model year Immobilizer Workshop
Manual.
Throttle Position (TP) Sensor
The throttle position (TP) sensor is a potentiometer
connected to the throttle shaft on the throttle body. The
PCM monitors the voltage on the signal line and
calculates throttle position. As the throttle valve angle is
changed (accelerator pedal moved), the TP sensor signal
also changes. At a closed throttle position, the output of
6G–7 ENGINE LUBRICATION
Oil Pan and Crankcase
Removal
1. Disconnect battery ground cable.
2. Drain engine oil.
3. Lift vehicle by supporting the frame.
4. Remove front wheels.
5. Remove oil level dipstick from level gauge tube.
6. Remove stone guard.
7. Remove radiator under fan shroud.
8. Remove suspension cross member fixing bolts, 2 pcs
each per side and remove suspension cross member.
9. Remove pitman arm and relay lever assembly, using
the 5–8840–2005–0 remover, remove pitman arm
from the steering unit and remove four fixing bolts for
relay lever assembly.
10. Remove axle housing assembly four fixing bolts from
housing isolator side and mounting bolts from wheel
side. At this time support the axle with a garage jack
and remove axle housing assembly.
11. Remove oil pan fixing bolts.
12. Remove oil pan, using 5–8840–2153–0 sealer cutter,
remove oil pan.
013RS003
13. Remove crankcase fixing bolts.
14. Remove crankcase, using 5–8840–2153–0 sealer
cutter, remove crankcase.
NOTE: Do not deform or damage the flange of oil pan and
crankcase.
Replace the oil pan and/or crankcase if deformed or dam-
aged.
013RS003
Installation
1. Install crankcase.
1. Remove residual sealant, lubricant and moisture
from mounting surface, then dry thoroughly.
2. Properly apply a 4.5 mm (0.7 in) wide bead of
sealant (TB-1207C or equivalent) to mounting
surface of crankcase.
Sealant beat must be continuous.
The crankcase must be installed within 5
minutes after sealant application before the
sealant hardens.
013RW010
6G–8
ENGINE LUBRICATION
3. Install crankcase, tighten crankcase fixing bolts
to the specified torque.
Torque : 10 Nꞏm (1.0 Kgꞏm/89 lb in)
013RW004
2. Install oil pan
1. Remove residual sealant, lubricant and moisture
from mounting surface, then dry thoroughly.
2. Properly apply a 4.5 mm (07 in) wide bead of
sealant (TB-1207C or equivalent) to mounting
surface of oil pan.
Sealant beat must be continuous.
The crankcase must be installed within 5
minutes after sealant application befor the
sealant hardens.
013RW003
3. Install oil pan, tighten oil pan fixing bolts to the
specified torque.
Torque : 25 Nꞏm (2.5 Kgꞏm/18 lb ft)3. Install axle housing assembly and tighten fixing bolts
to the specified torque.
Axle case bolts
Torque : 82 Nꞏm (8.4 Kgꞏm/60 lb ft)
Mounting bolts
Torque : 152 Nꞏm (15.5 Kgꞏm/112 lb ft)
013RW005
4. Install relay lever assembly and tighten fixing bolts.
Torque: 44 Nꞏm (4.5 Kgꞏm/32 lb ft)
5. Engage teeth of pitman arm and steering unit, and
tighten nut to the specified torque.
Torque : 216 Nꞏm (22.0 Kgꞏm/159 lb ft)
013RW006
Legend
(1) Pitman Arm
(2) Relay Lever
6A – 52 ENGINE MECHANICAL
TIMING GEAR
REMOVAL
1. Loosen fixing bolt for generator and remove
generator assembly.
2. Remove fixing nuts, then remove cooling fan
assembly and fan pulley.
3. Remove crankshaft damper pulley.
4. Belt cover
1) Disconnect harness connector of CMP
(camshaft position) sensor.
2) Remove CMP sensor.
3) Remove belt cover.
5. Loosen belt tensioner to remove timing belt.
6. Remove camshaft pulley.
7. Remove high pressure oil pump pulley.
8. Remove front plate.
9. Remove vacuum pump.
10. Remove power steering pump.
11. Remove gear cover assembly.
12. Idle gear A.
1) Set two bolts to sub gear of idle gear A and turn
it to align the tooth of idle gear A then lock them
by bolt as show in the illustration.
2) Remove idle gear A fixing bolts.
3) Remove idle gear A.Legend
(1) Sub-Gear
(2) Main Gear
(3) Bar
(4) Locking Bolt
2
3
4
5 8
7
6 91
020RW028
Legend
(1) Idle Gear A
(2) High Pressure Oil Pump Gear
(3) Vacuum Pump Gear
(4) Power Steering Pump Gear(5) Balance Gear LH
(6) Idle Gear C
(7) Crankshaft Gear
(8) Balance Gear RH
(9) Idle Gear B
4 1
2
3
014RW177
ENGINE MECHANICAL 6A – 57
10. Vacuum pump
1) Install vacuum pump and tighten bolts to
specified torque.
Torque: 25 Nꞏm (2.5 kgꞏm / 18 lb ft)
2) Install noise insulator cover.
11. Power steering pump (P/S)
1) Install P/S pump.
Torque: 25 Nꞏm (2.5 kgꞏm / 18 lb ft)12. Install front plate.
Torque: 20 Nꞏm (2.0 kgꞏm / 14.5 lb ft)
13. High pressure oil pump pulley.
1) Install oil pump pulley and tighten to specified
torque.
Torque:10 Nꞏm (1.0 kgꞏm / 7.2 lb ft)
2
2~2.5mm
2~2.5mm
Apply liquid gasket around inside
of the bolt hole
Bolt hole
Inside
Outside
F06HX00001
052RW001
430RW017
012RW035