6E–25 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
General Service Information
Serviceability Issues
Non-OEM Parts
All of the OBD diagnostics have been calibrated to run
with OEM parts. Accordingly, if commercially sold sensor
or switch is installed, it makes a wrong diagnosis and turn
on the MIL (“Check Engine” lamp).
Aftermarket electronics, such as cellular phones,
stereos, and anti-theft devices, may radiate EMI into the
control system if they are improperly installed. This may
cause a false sensor reading and turn on the MIL (“Check
Engine” lamp).
Poor Vehicle Maintenance
The sensitivity of OBD diagnostics will cause the MIL
(“Check Engine” lamp) to turn on if the vehicle is not
maintained properly. Restricted oil filters, fuel filters, and
crankcase deposits due to lack of oil changes or improper
oil viscosity can trigger actual vehicle faults that were not
previously monitored prior to OBD. Poor vehicle
maintenance can not be classified as a “non-vehicle
fault”, but with the sensitivity of OBD diagnostics, vehicle
maintenance schedules must be more closely followed.
Related System Faults
Many of the OBD system diagnostics will not run if the
ECM detects a fault on a related system or component.
Visual/Physical Engine Compartment
Inspection
Perform a careful visual and physical engine
compartment inspection when performing any diagnostic
procedure or diagnosing the cause of an emission test
failure. This can often lead to repairing a problem without
further steps. Use the following guidelines when
performing a visual/physical inspection:
Inspect all vacuum hoses for punches, cuts,
disconnects, and correct routing.
Inspect hoses that are difficult to see behind other
components.
Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
This vehicle utilizes the “Class II” communication system.
Each bit of information can have one of two lengths: longor short. This allows vehicle wiring to be reduced by
transmitting and receiving multiple signals over a single
wire. The messages carried on Class II data streams are
also prioritized. If two messages attempt to establish
communications on the data line at the same time, only
the message with higher priority will continue. The device
with the lower priority message must wait.
On this vehicle the Tech 2 displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:
The diagnostic test has been completed since the last
ignition cycle.
The diagnostic test has passed during the current
ignition cycle.
The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:
The diagnostic test has been completed since the last
ignition cycle.
The fault identified by the diagnostic test is currently
active.
The fault has been active during this ignition cycle.
The operating conditions at the time of the failure.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to operate engine properly.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable. Accel
Position (AP) sensor that indicates high throttle position
at low engine loads or MAP voltage. Input components
may include, but are not limited to the following sensors:
Intake Air Temperature (IAT) Sensor
Crankshaft Position (CKP) Sensor
Intake throttle Position (ITP) Sensor
Engine Coolant Temperature (ECT) Sensor
Camshaft Position (CMP) Sensor
Manifold absolute Pressure (MAP) Sensor
Accel Position Sensor
Fuel Temp Sensor
Rail Pressure Sensor
Oil Temp Sensor
EGR Pressure Sensor
Vehicle Speed Sensor
TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–19
C07RT006
Class 2 data is also pulse width modulated. Each bit of
information can have one of two lengths: long or short. On
the other hand, UART data bits come in only one length
(short). The pulse width modulation of Class 2 data allows
better utilization of the data line.
The message carried on Class 2 data streams are also
prioritized. This means that if two devices try to
communication on the data line at the same time, only the
higher priority message will continue. The device with the
lower priority message must wait.
NOTE: The Class 2 data wire is always terminal 2 of the
new 16–terminal Data Link Connector (DLC).
16 – Terminal Data Link Connector (DLC)
OBD II standardizes Data Link Connector (DLC)
configurations. The DLC, formerly referred to as the
ALDL, will be a 16–terminal connector found on the lower
left side of the driver’s side instrument panel. All
manufacturers must conform to this 16–terminal
standard.
821RW262
TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–67
DTC P1850 Brake Band Apply Solenoid Malfunction
D07RW009
Circuit Description
The brake band apply solenoid is a normally open
solenoid which controls the flow of fluid for brake band
application. The Powertrain Control Module (PCM)
uses Pulse Width Modulation (PWM) and changes
the duty cycle to control the solenoid. The PCM turns
the solenoid on (energized) and off (deenergized) at a
constant frequency. The length of time the solenoid is
energized during each on/off cycle is called the pulse
width. By varying or “modulating” the pulse width, the
solenoid output pressure is changed. Since the
solenoid is normally open, increasing the pulse width
increases the duty cycle and decreases the output
pressure. PWM control provides smooth band
application without an accumulator. The band is only
applied in first and second gears.
In the event of an electrical failure (open), the
solenoid regulates at the maximum oil flow (0% duty
cycle).
The solenoid is activated by current. This current is
produced by applying a voltage to one side (the High
side) and a ground to the other side (Low side).
The High Side Driver (HSD) is a circuit of the PCM
that acts as a switch between the solenoids and the
supply voltage. The High side of the solenoid is
permanently supplied with voltage. When the ignition
is off, the HSD is turned off.This DTC detects a continuous open or short to ground in
the brake band apply solenoid circuit or the brake band
apply solenoid. This is a type “D” DTC.
Conditions For Setting The DTC
Battery voltage is between 10 and 16 volts.
Ignition is “on”, Engine “run”.
The PCM commands the solenoid “on” and the
voltage remains high (B+) or the PCM commands the
solenoid “off” and the voltage remains low (zero
volts).
All conditions met in 1.3 seconds.
Action Taken When The DTC Sets
Inhibit brake band apply solenoid.
The PCM will not illuminate the CHECK TRANS
Lamp.
Conditions For Clearing The DTC
The DTC can be cleared from the PCM history by
using a scan tool.
The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.
The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.
CLUTCH7C–23
Disassembly
(4JX1)
1. Remove damper cylinder assembly and gasket.
2. Remove push rod damper.
NOTE: The master cylinder assembly cannot be
disassembled because of point–staked rod stopper.
Inspection and Repair
Clean and inspect the removed parts.
Make necessary parts replacement if any abnormalities
such as wear, oil leaks or other damage are found through
inspection.
Reassembly
To reassemble, follow the disassembly steps in the
reverse order, noting the following points:
1.Push rod set length
RHD: 117.5 mm (4.626 in)
LHD: 119 mm (4.685 in)
2.Push rod nut torque
17 Nꞏm (1.7 kgꞏm/12 Ib ft)
3.Damper cylinder torque
47 Nꞏm (4.8 kgꞏm/35 Ib ft)
WIPER/WASHER SYSTEM8B–11
Rear Washer Spray Pattern
885RS003
Legend
(1) Washer Nozzle
(2) Spray Target
Rear Wiper Blade Rubber
Removal and Installation
Refer to the Windshield Wiper Blade Rubber in this
section.
Headlight Wiper/Washer
General Description
The circuit consists of the starter switch, headlight
wiper/washer switch, headlight wiper motor and washer
motor. By pushing the headlight wiper/washer switch with
the starter switch on, the wiper will make 5 strokes with
washer solution applied between each of the first 4
strokes, regardless of the length of time the switch is held
down.
The washer nozzle is installed to the wiper blade, and the
tank to which the washer motor is installed shared among
the headlight washer and the windshield washer.
The chassis electrical system is a 12–volt system with a
negative ground polarity.
Wire size are appropriate to respective circuits, and
classified by color. (The classification of harnesses by
color is shown on the circuit diagram for ease of harness
identification.)
The wire size is determined by load capacity and the
length of wire required.
The vehicle harnesses are: body harness, chassis
harness, engine room harness, instrument harness,
transmission harness, engine ECGI harness, dome light
harness, door harness, rear body harness, tailgate
harness, SRS harness and battery cables.
The harnesses are protected either by tape or corrugated
tube, depending on harness location.
The circuit for each system consists of the power source,
wire, fuse, relay, switch, load parts and ground, all of
which are shown on the circuit diagram.
In this section, each electrical device is classified by
system.
For major parts shown on the circuit based on the circuit
diagram for each system, a summary, diagnosis of
troubles and inspection procedures are detailed.
Notes for Working on Electrical
Items
Disconnecting the Battery Cable
1. All switches should be in the “OFF” position.
2. Disconnect the battery ground cable (2).
3. Disconnect the battery positive cable (1).
CAUTION: It is important that the battery ground
cable be disconnected first. Disconnecting the
battery positive cable first can result in a short circuit.
Connecting the Battery Cable
Follow the disconnecting procedure in the reverse order.CAUTION: Clean the battery terminal and apply a
light coat of grease to prevent terminal corrosion.
Disconnecting the Connector
Some connectors have a tang lock to hold the connectors
together during vehicle operation.
Some tang locks are released by pulling them towards
you (1).
Other tang locks are released by pressing them forward
(2).
Determine which type of tang lock is on the connector
being handled.
Firmly grasp both sides (male and female) of the
connector (3).
Release the tang lock and carefully pull the two halves of
the connector apart.
Never pull on the wires to separate the connectors (4).
2
1
General Description
1
2
3
4
5. The wiring harness between engine and chassis
should be long enough (2). Tension of the wire (1) may
causes chafing or damage due to various vibrations.
Splicing Wire
1. If the harness is taped, remove the tape. To avoid wire
insulation damage, use a sewing “seam ripper”
(available from sewing supply stores) to cut open the
harness.
If the harness has a black plastic conduit, simply pull
out the desired wire.
2. Begin by cutting as little wire off the harness as
possible. You may need the extra length of wire later
if you decide to cut more wire off to change the location
of a splice. You may have to adjust splice locations to
make certain that each splice is at least 1–1/2”
(40 mm) away from other splices, harness branches,
or connectors.
3 . W h e n r e p l a c i n g a w i r e , u s e a w i r e o f t h e s a m e s i z e a s
the original wire.
Check the stripped wire for nicks or cut stands. If the
wire is damaged, repeat the procedure on a new
section of wire. The two stripped wire ends should be
equal in length.
4. Select the proper clip to secure the splice.
To determine the proper clip size for the wire being
spliced, follow the directions included with your clips.
Select the correct anvil on the crimper. (On most
crimpers your choice is limited to either a small or
large anvil.)
Overlap the two stripped wire ends and hold them
between your thumb and forefinger as shown in the
figure.
The center the spline clip (1) under the stripped wires
and hold it in place.
Open the crimping tool to its full width and rest one
handle on a firm flat surface.
Center the back of the splice clip on the proper anvil
and close the crimping tool to the point where the back
of the splice clip touches the wings of the clip.
Make sure that the clip and wires are still in the correct
position. Then, apply steady pressure until the
crimping tool closes as shown in the figure.
2
11
Wiring – Wire Size
The size of wire used in a circuit is determined by the
amount of current (amperage), the length of the circuit,
and the voltage drop allowed. The following wire size and
load capacity, shown below, are specified by AWG
(American Wire Gauge). (Nominal size means
approximate cross sectional area (1).)
Wiring – Wire Size Table
Nominal sizeCross sectional Outside diameter Allowable
area (mm2) (mm) current (A)
0.3 0.372 1.5 9
0.5 0.563 1.7 12
0.85 0.885 1.9 16
1.25 1.287 2.2 21
22.0912.728
3 3.296 3.6 37.5
55.2274.453
87.9525.567
15 13.36 7.0 75
20 20.61 8.2 97
1