Diagnosis Description
DESCRIPTION
The CVT 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. A malfunction is indicated by the MIL (Malfunction Indicator Lamp) and is stored as a DTC in the ECM memory and in the TCM memory.
The second is the TCM original self-diagnosis performed by the TCM. A malfunction history is stored in the TCM memory. The detected items are overlapped with OBD-II self-diagnostic items. For details, refer to TM- 124, "DTC Index".
OBD-II FUNCTION
The ECM provides emission-related on board diagnostic (OBD-II) functions for the CVT system. One function is to receive a signal from the TCM used with OBD-related parts of the CVT 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 relation to CVT system parts.
ONE OR TWO TRIP DETECTION LOGIC OF OBD-II
One Trip Detection Logic If a malfunction is sensed during the first test drive, the MIL illuminates and the ECM memory stores the malfunction as a DTC. The TCM is not provided with such a memory function.
Two Trip Detection Logic
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 does not illuminate. - 1st trip If the same malfunction as that experienced during the first test drive is sensed during the second test drive, the MIL will illuminate. - 2nd trip 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)
How to Read DTC and 1st Trip DTC
DTC and 1st trip DTC can be read by the following methods.
( with CONSULT or
GST) CONSULT or GST (Generic Scan
Tool) Examples: P0705, P0720, etc.
These DTC are prescribed by SAE J2012.
(CONSULT also displays the malfunctioning component or system.)
Freeze Frame Data and 1st Trip Freeze Frame Data
Data that are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data, and the data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT or GST. The 1st trip freeze frame data can only be displayed on the CONSULT screen, not on the GST.
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority for 1st trip freeze frame data, and it is updated each time a different 1st trip DTC is detected. However, once freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the following priorities to update the data.
Both 1st trip freeze frame data and freeze frame data (along with the DTC) are cleared when the ECM memory is erased.
How to Erase DTC
How to Erase DTC (With CONSULT)
The emission related diagnostic information in the TCM and ECM can be erased by selecting "ALL Erase" in the "Description" of "FINAL CHECK" mode with CONSULT.
How to Erase DTC (With GST)
MALFUNCTION INDICATOR LAMP (MIL)
Description
The MIL is located on the instrument panel.
If the MIL remains ON, the on board diagnostic system has detected an engine system malfunction.
B261A push-button ignition switch
Description
IPDM E/R transmits the push-button ignition switch status via CAN
communication to BCM. BCM receives
push-button ignition switch status by hardwire input. BCM compares the 2 signals
for mismatch.
DTC Logic
DTC DETECTION LOGIC
NOTE:
If DTC B261A is displayed with DTC U1000, ...
P0744 torque converter
Description
This malfunction is detected when the torque converter clutch does not
lock-up as instructed by the TCM. This
is not only caused by electrical malfunctions (circuits open or shorted), but
also by mechanical malfunctions
such as control valve sticking, improper solenoid valve ope ...
Mode door control system
System Diagram
System Description
The mode door is automatically controlled by the temperature setting, ambient
temperature, in-vehicle temperature,
intake temperature and amount of sunload.
SYSTEM OPERATION
The A/C auto amp. receives data from each of the sensors.
The A/C auto amp. ...