On-Board Diagnostic System

OBD II SYSTEM OPERATING CHART:

THE RELATIONSHIP OF MIL, DTC AND DRIVING PATTERN
In the case of MIL "ON"...

1. When the same malfunction is detected and maintained during subsequent sequential two driving cycles, MIL will automatically light up.
2. MIL will go off automatically after 3 subsequent sequential driving cycles without same malfunctions.
3. After the ECM first detects a malfunction, a diagnostic trouble code is recorded when the engine is restarted and the same malfunctions is re-detected. However, for misfire and CKP sensor a diagnostic trouble codes are recorded on the first detection of the malfunction.
4. After recording the diagnostic trouble code, if the ECM does not re-detect the malfunction for 80 warm-up cycles, the diagnostic trouble code will be released automatically from the ECM memory.

NOTE:
1. A "warm-up cycle" means sufficient vehicle operation such that the coolant temperature has risen by at least 40 degrees Fahrenheit from engine starting and reaches a minimum temperature of 160 degrees Fahrenheit.
2. A "driving cycle" consists of engine start-up, vehicle operation beyond the beginning of closed loop operation.





MALFUNCTION INDICATOR LAMP (MIL)
An On Board Diagnostic lamp comes on to notify the driver that there are any problems on the vehicle.

The Malfunction Indicator Lamp (MIL) request signal wire is used by the Transaxle Control Module (TCM) to signal the ECM to set transaxle related codes.

However the MIL will go off automatically after 3 subsequent sequential trips without same malfunctions.

Immediately after the ignition switch is turn on (ON position), the malfunction indicator lamp is lit continuously to indicate that the malfunction indicator lamp operates normally.

The Following Items will be Indicated by the MIL
- Catalyst
- Fuel system
- Mass Air Flow (MAF) Sensor
- Intake Air Temperature (IAT) Sensor
- Engine Coolant Temperature (ECT) Sensor
- Throttle Position Sensor (TPS)
- Upstream Oxygen Sensor
- Downstream Oxygen Sensor Heater
- Downstream Oxygen Sensor
- Upstream Oxygen Sensor Heater
- Injector
- Fuel Tank Pressure (FTP) sensor
- Misfire
- Crankshaft Position (CKP) Sensor
- Camshaft Position (CMP) Sensor
- Evaporative Emission Control System
- Canister Close Valve (CCV)
- Vehicle Speed Sensor (VSS)
- Idle Control Valve
- Power Supply
- ECM
- MT/AT Encoding
- Acceleration Sensor
- MIL-On Request Signal Power Stage

SELF-DIAGNOSIS
The ECM monitors the input/output signals (some signals at all times and the others under specified conditions). When the ECM detects that an irregularity, it memorizes the diagnostic trouble codes, and outputs the signal to the self-diagnosis output terminal.

The diagnosis results can be read out by using a Scan Tool (ST).

The diagnostic trouble code (DTC) will remain in the ECM as long as battery power is maintained. The diagnostic trouble code will, however, be erased when the battery terminal or the engine control module (ECM) connector is disconnected or erased by Generic Scan Tool.