DIAGNOSIS SYSTEM
AT–36
A750E AUTOMATIC TRANSMISSION – AUTOMATIC TRANSMISSION SYSTEM
DIAGNOSIS SYSTEM
1.
FI00534E02
Intelligent Tester
CAN VIM
DLC3
AT
H102157E03
DESCRIPTION
(a) When troubleshooting On-Board Diagnostic (OBD
II) vehicles, the vehicle must be connected to the
intelligent tester (complying with SAE J1987).
Various data output from the vehicle's ECM can
then be read.
(b) OBD II regulations require that the vehicle's onboard computer illuminate the Malfunction Indicator
Lamp (MIL) on the instrument panel when the
computer detects a malfunction in:
1. The emission control system/components
2. The power train control components (which affect
vehicle emissions)
3. The computer
In addition, the applicable Diagnostic Trouble Codes
(DTCs) prescribed by SAE J2012 are recorded in
the ECM memory.
If the malfunction does not recur in 3 consecutive
trips, the MIL turns off automatically but the DTCs
remain recorded in the ECM memory.
(c) To check DTCs, connect the intelligent tester to the
Data Link Connector 3 (DLC3) of the vehicle. The
intelligent tester displays DTCs, the freeze frame
data and a variety of the engine data.
The DTCs and freeze frame data can be erased
with the intelligent tester (See page AT-33).
(d) In order to enhance OBD function on vehicles and
develop the Off-Board diagnosis system, CAN
communication has been introduced in this system
(CAN: Controller Area Network). It minimizes the
gap between technician skills and vehicle
technology. CAN is a network, which uses a pair of
data transmission lines, spanning multiple
computers and sensors. It allows high speed
communication between the systems and
simplification of the wire harness connection. Since
this system is equipped with CAN communication,
CAN VIM (VIM: Vehicle Interface Module)
connecting with intelligent tester is necessary to
display any information from the ECM on the tester.
(Also communication between the intelligent tester
and the ECM uses a CAN communication signal.)
When confirming DTCs and any data of the ECM,
connect the CAN VIM between the DLC3 and the
intelligent tester.
A750E AUTOMATIC TRANSMISSION – AUTOMATIC TRANSMISSION SYSTEM
2.
3.
4.
0.5
0.5
A092901E12
5.
DLC3
CG
SG
NORMAL MODE AND CHECK MODE
(a) The diagnosis system operates in "normal mode"
during normal vehicle use. In normal mode, "2 trip
detection logic" is used to ensure accurate detection
of malfunctions. "Check mode" is also available to
technicians as an option. In check mode, "1 trip
detection logic" is used for simulating malfunction
symptoms and increasing the system's ability to
detect malfunctions, including intermittent
malfunctions.
2 TRIP DETECTION LOGIC
(a) When a malfunction is first detected, the
malfunction is temporarily stored in the ECM
memory (1st trip). If the ignition switch is turned
OFF and then ON again, and the same malfunction
is detected again, the MIL will illuminate.
FREEZE FRAME DATA
(a) Freeze frame data records the engine conditions
(fuel system, calculated load, engine coolant
temperature, fuel trim, engine speed, vehicle speed,
etc.) when a malfunction is detected. When
troubleshooting, freeze frame data can help
determine if the vehicle was running or stopped, if
the engine was warmed up or not, if the air-fuel ratio
was Lean or Rich, and other data from the time the
malfunction occurred.
(b) The ECM records engine conditions in the form of
freeze frame data every 0.5 seconds. Using the
intelligent tester, five separate sets of freeze frame
data, including the data values at the time when the
DTC was set, can be checked.
• 3 data sets before the DTC was set
• 1 data set when the DTC was set
• 1 data set after the DTC was set
These data sets can be used to simulate the
condition of the vehicle around the time the
occurrence of the malfunction. The data may assist
in identifying of the cause of the malfunction, and in
judging whether it was temporary or not.
(Seconds)
0.5
AT–37
CANH SIL
DATA LINK CONNECTOR 3 (DLC3)
(a) The vehicle's ECM uses the ISO 15765-4
communication protocol. The terminal arrangement
of the DLC3 complies with SAE J1962 and matches
the ISO 15765-4 format.
1 2 3 4 5 6 7 8
9 10 11 1213141516
CANL
Symbols (Terminal No.)
BAT
A082779E81
Terminal Description
Condition
Specified Condition
SIL (7) - SG (5)
Bus "+" line
During transmission
Pulse generation
CG (4) - Body ground
Chassis ground
Always
Below 1 Ω
AT
AT–38
AT
A750E AUTOMATIC TRANSMISSION – AUTOMATIC TRANSMISSION SYSTEM
Symbols (Terminal No.)
Terminal Description
Condition
Specified Condition
SG (5) - Body ground
Signal ground
Always
Below 1 Ω
BAT (16) - Body ground
Battery positive
Always
CANH (6) - CANL (14)
CAN bus line
CANH (6) - CG (4)
HIGH-level CAN bus line
Ignition switch OFF*
200 Ω or higher
CANL (14) - CG (4)
LOW-level CAN bus line
Ignition switch OFF*
200 Ω or higher
CANH (6) - BAT (16)
HIGH-level CAN bus line
Ignition switch OFF*
6 kΩ or higher
CANL (14) - BAT (16)
LOW-level CAN bus line
Ignition switch OFF*
6 kΩ or higher
6.
7.
8.
Ignition switch
11 to 14 V
OFF*
54 to 69 Ω
NOTICE:
*
: Before measuring the resistance, leave the
vehicle as is for at least 1 minute and do not
operate the ignition switch, any other switches
or the doors.
If the result is not as specified, the DLC3 may have
a malfunction. Repair or replace the harness and
connector.
HINT:
Connect the cable of the intelligent tester to the
DLC3, turn the ignition switch to the ON position
and attempt to use the intelligent tester. If the
screen displays UNABLE TO CONNECT TO
VEHICLE, a problem exists in the vehicle side or the
tester side.
If the communication is normal when the tester is
connected to another vehicle, inspect the DLC3 on
the original vehicle.
If the communication is still impossible when the
tester is connected to another vehicle, the problem
is probably in the tester itself. Consult the Service
Department listed in the tester's instruction manual.
CHECK BATTERY VOLTAGE
Standard voltage:
11 to 14 V
(a) If the voltage is below 11 V, replace the battery
before proceeding.
CHECK MIL
(a) Check that the MIL illuminates when turning the
ignition switch ON.
If the MIL does not illuminate, there is a problem in
the MIL circuit (See page ES-404).
(b) When the engine is started, the MIL should turn off.
ALL READINESS
(a) For this vehicle, using the intelligent tester allows
readiness codes corresponding to all DTCs to be
read. When diagnosis (normal or malfunctioning)
has been completed, readiness codes are set. Enter
the following menus: ENHANCED OBD II /
MONITOR INFO on the intelligent tester.
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