DRIVEABILITY AND EMISSIONS 6E1-45
BASIC KNOWLEDGE OF TOOLS
REQUIRED
Notice: 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
effectively use this section of the Service Manual.
SERIAL DATA COMMUNICATIONS
This vehicle utilizes the serial data communication
system. Each bit of information can have one of two
lengths: long or short. This allows vehicle wiring to be
reduced by transmitting and receiving multiple signals
over a single wire. The messages carried on serial
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. For more information on this
system of coding, refer to Decimal/ Binary/
Hexadecimal Conversions. On this vehicle the Scan
Tool 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
Miscellaneous Test:
A miscellaneous test is a kind of the On-Board
Diagnostics.
Using a tech 2, the miscellaneous test can be
conducted, followings are brief description about the
miscellaneous tests.
To perform the miscellaneous test, allows the
displayed menu on the tech 2. Sub-menu of
miscellaneous test are as follows.
• Check powertrain lamp:
This test allows to turn on and off the powertrain
warning lamp in the instrument cluster.
• Fuel Pump:
Fuel pump test allows to turn on and off the fuel
pump.
If turned off while the engine is running, the engine
will stall.
• A/C Clutch:
The A/C Clutch test allows to turn on and off the
airconditioning.
• Canister Purge Control Solenoid Valve:
This function takes control of the canister purge
control solenoid valve.
The on command represents a 100% pwm, the off
command a 0% pwm.
• IAC (Idle Air Control) System:
• RPM control
This function allows the user to slew the desired
RPM via increments of 25 RPM with a minimum
of 600 RPM and a maximum of 2000 RPM.
The start value will be at 1150 RPM.
• IAC Control
This function allows the user to slew the IAC via
increments of 25 steps with a minimum of 0 steps
and a maximum of 250 steps.
The start value will be at idle steps.
• IAC Reset
The user will have the ability to perform an IAC
reset.
Each keypress will actuate the command to reset.
• Fuel Trim Reset:
This function allows the user to command the ECM
to perform an Long Term Fuel Trim reset, also
known as a Block Learn Memory reset.
Each keypress will actuate the command to reset.
• Fueling Mode:
This function provides the user with the ability to
enable or disable closed loop fuel control.
• Air Fuel Ratio:
This function allows the user to slew the control
state of the A/F ratio within a minimum of 11.7:1
and a maximum of 17.7:1.
The test starts at an A/F ratio of 14.7 : 1.
The incremental control is 0.5 steps per keypress.
COMPREHENSIVE COMPONENT
MONITOR DIAGNOSTIC OPERATION
Comprehensive component monitoring diagnostics
are involved to monitor emissions-related input and
output engine components.
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