K121 CVT CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM DIAGNOSIS SYSTEM
CHINA NATIONWIDE STAGE 6
When troubleshooting On-Board Diagnostic (OBD) vehicles, an OBD scan tool (complying with ISO 15765-4) must be connected to the vehicle. Various data output from the vehicle's ECM can then be read.
OBD regulations require that the vehicle's on-board computer illuminate the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in:
The emission control system components.
The powertrain control components which affect vehicle emissions.
The computer.
In addition, the applicable Diagnostic Trouble Codes (DTCs) prescribed by ISO 15765-4 are stored in the ECM memory. If the malfunction does not reoccur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain stored in the ECM memory.
To check DTCs, connect the GTS or OBD scan tool to the Data Link Connector 3 (DLC3) of the vehicle.
The scan tool displays DTCs, the Freeze Frame Data and a variety of engine data.
The DTCs and Freeze Frame Data can be cleared using the scan tool.
NORMAL MODE AND CHECK MODE (GTS Only)
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 when reproducing malfunction symptoms for increasing the ability of the system to detect malfunctions, including intermittent malfunctions.
2-TRIP DETECTION LOGIC
When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip). If the same malfunction is detected during the subsequent driving cycle, the MIL is illuminated (2nd trip).
FREEZE FRAME DATA
The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was moving or stationary, whether the engine was warmed up or not and whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
The GTS displays freeze frame data recorded at five different points: 1) 3 times before the DTC is stored, 2) once when the DTC is stored, and 3) once after the DTC is stored. The data can be used to reproduce the vehicle condition around the time of the malfunction. The data may be helpful in determining the cause of a malfunction. It may also be helpful in determining whether a DTC is being caused by a temporary malfunction.
LIST OF FREEZE FRAME DATA
- Powertrain > Engine
-
Tester Display Total Distance Traveled Total Distance Traveled - Unit Vehicle Speed Engine Speed Mass Air Flow Sensor Intake Manifold Absolute Pressure Intake Manifold Absolute Pressure Supported Coolant Temperature Throttle Motor Duty Ratio Neutral Control N Range Status Starter SW Shift SW Status (Neutral) Supported Neutral Position Relay Drive Status Shift Sensor Switch DB1 Shift Sensor Switch DB2 Shift Sensor Switch SPN Shift Sensor Switch SPR Shift Sensor Switch SPP Shift Sensor Switch PNB Shift Sensor Switch RP Stop Light SW NSS Sensor Speed NSS Sensor Voltage NO Sensor Speed NO Sensor Voltage NT Sensor Speed NC1 Sensor Speed NC1 Sensor Voltage Belt Clamping Force Sensor Shift Range for Control Shift Range for Display Shift SW Status (N,P Range) Shift SW Status (N,P Range) Supported Sport Shift Up SW Sport Shift Down SW Shift SW Status (S Range) A/T Oil Temperature No.1 ATF Thermal Degradation Estimate CVT Oil Press Calibration NT Sensor Voltage Drive Mode Status Mode Cancel SW Power Mode SW Synchronize Stroke Sensor Position Synchronize Stroke Sensor Voltage Status of Synchronize Lock Up Status CVT Shift Status Ratio Shift Mode Shift Range Indicator Shift Lock Release Request Solenoid (SLU) Solenoid (SLS) High/Low Solenoid (SLS) MAX/MIN Solenoid (SLP) Solenoid (SL1) Solenoid (SL2) Solenoid (SC1) Solenoid (SC2) Solenoid (SC3) Acceleration Sensor Value (Front and Back) Acceleration Sensor Value (Left and Right) D Shift Position Indicator Turn On Request N Shift Position Indicator Turn On Request R Shift Position Indicator Turn On Request P Shift Position Indicator Turn On Request B Shift Position Indicator Turn On Request Back Up Light Turn On Request
DATA LINK CONNECTOR 3 (DLC3)
BATTERY VOLTAGE
- Standard voltage:
11 to 14 V
If the voltage is below 11 V, recharge or replace the battery.
MIL (Malfunction Indicator Lamp)
The MIL is illuminated when the ignition switch is turned to ON (with the engine not running).
If the MIL does not illuminate, check the MIL circuit.
for M20C-FKS:
for M20D-FKS:
The MIL will turn off when the engine is started. If the MIL remains illuminated, the diagnosis system has detected a malfunction or abnormality in the system.