Introduction
NBAT0014
The A/T system has two self-diagnostic systems.
The first is the emission-related on board diagnostic system (OBD-II) performed by the TCM in combination
with the ECM. The malfunction is indicated by the MIL (malfunction indicator lamp) and is stored as a DTC in
the ECM memory but not the TCM memory.
The second is the TCM original self-diagnosis indicated by the O/D OFF indicator lamp. The malfunction is
stored in the TCM memory. The detected items are overlapped with OBD-II self-diagnostic items. For detail,
refer to AT-38.
OBD-II Function for A/T System
NBAT0182
The ECM provides emission-related on board diagnostic (OBD-II) functions for the A/T system. One function
is to receive a signal from the TCM used with OBD-related parts of the A/T system. The signal is sent to the
ECM when a malfunction occurs in the corresponding OBD-related part. The other function is to indicate a
diagnostic result by means of the MIL (malfunction indicator lamp) on the instrument panel. Sensors, switches
and solenoid valves are used as sensing elements.
The MIL automatically illuminates in One or Two Trip Detection Logic when a malfunction is sensed in rela-
tion to A/T system parts.
One or Two Trip Detection Logic of OBD-II
NBAT0015
ONE TRIP DETECTION LOGIC
NBAT0015S01
If a malfunction is sensed during the first test drive, the MIL will illuminate and the malfunction will be stored
in the ECM memory as a DTC. The TCM is not provided with such a memory function.
TWO TRIP DETECTION LOGIC
NBAT0015S02
When a malfunction is sensed during the first test drive, it is stored in the ECM memory as a 1st trip DTC
(diagnostic trouble code) or 1st trip freeze frame data. At this point, the MIL will not illuminate. — First Trip
If the same malfunction as that experienced during the first test drive is sensed during the second test drive,
the MIL will illuminate. — Second Trip
A/T-related parts for which the MIL illuminates during the first or second test drive are listed below.
Items
MIL
One trip detection
Two trip detection
Shift solenoid valve A — DTC: P0750
X
Shift solenoid valve B — DTC: P0755
X
Throttle position sensor or switch — DTC: P1705
X
Except above
X
The “trip” in the “One or Two Trip Detection Logic” means a driving mode in which self-diagnosis is performed
during vehicle operation.
OBD-II Diagnostic Trouble Code (DTC)
NBAT0016
HOW TO READ DTC AND 1ST TRIP DTC
NBAT0016S01
DTC and 1st trip DTC can be read by the following methods.
(
with CONSULT-II or
GST) CONSULT-II or GST (Generic Scan Tool) Examples: P0705, P0710, P0720,
P0725, etc.
These DTCs are prescribed by SAE J2012.
(CONSULT-II also displays the malfunctioning component or system.)
I
1st trip DTC No. is the same as DTC No.
I
Output of the diagnostic trouble code indicates that the indicated circuit has a malfunction.
However, in case of the Mode II and GST they do not indicate whether the malfunction is still
occurring or occurred in the past and returned to normal.
CONSULT-II can identify them as shown below. Therefore, using CONSULT-II (if available) is rec-
ommended.
A sample of CONSULT-II display for DTC and 1st trip DTC is shown on the next page. DTC or 1st trip DTC
of a malfunction is displayed in SELF-DIAGNOSTIC RESULTS mode for “ENGINE” with CONSULT-II. Time
data indicates how many times the vehicle was driven after the last detection of a DTC.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Introduction
AT-33