If any component of the gasoline engine control system (sensors, ECM, injector, etc.) malfunctions, fuel supply may stop or an incorrect amount of fuel may be supplied under various engine operating conditions. The following situations may occur.
Engine is hard to start or does not start at all.
Unstable idle.
Poor drivability
If any of the above conditions are noted, first perform routine diagnostics, including basic engine checks (ignition system malfunction, adjustment, etc.). Then inspect the gasoline engine control system components with HI-SCAN (Pro).
Before removing or installing any part, read the diagnostic trouble codes, then disconnect the negative (-) battery terminal.
Before disconnecting the battery cable, turn the ignition switch to the OFF position. Removing or connecting the battery cable while the engine is running or the ignition is ON may damage the ECM.
The control harnesses between the ECM and the heated oxygen sensor are covered with shielded ground wires to the body to prevent the effects of ignition noise and radio interference. If the shielded wire is faulty, the control harness must be replaced.
When checking the generator charging condition, do not disconnect the battery positive (+) terminal to protect the ECM from damage due to voltage.
When charging the battery with an external charger, disconnect the battery terminals on the vehicle side to prevent damage to the ECM.
Malfunction Indicator Lamp (MIL) [OBD] The malfunction indicator lamp illuminates to notify the driver that a malfunction has occurred in the vehicle. However, the MIL will go off automatically after 3 consecutive driving cycles without the same malfunction. Immediately after the ignition switch is turned ON (ON position without starting), the MIL will illuminate continuously to indicate that the MIL is operating normally. Malfunctions with the following items illuminate the MIL.
Catalyst
Fuel System
Manifold Absolute Pressure Sensor (MAPS)
Intake Air Temperature Sensor (IATS)
Engine Coolant Temperature Sensor (ECTS)
Throttle Position Sensor (TPS) [Built into ETC Module]
Upstream Oxygen Sensor
Upstream Oxygen Sensor Heater
Downstream Oxygen Sensor
Downstream Oxygen Sensor Heater
Injector
misfire
Crankshaft Position Sensor (CKPS)
Camshaft Position Sensor (CMPS)
Evaporative Emission Control System
Vehicle Speed Sensor (VSS)
ETC Motor [built into ETC module]
Power Supply
PCM/PCM
MT/AT Coding
Acceleration Sensor
MIL Request Signal
Power Stage
Refer to "DIAGNOSTIC TROUBLE CODE (DTC) CHART" for more information.
[Non-EOBD] The malfunction indicator lamp illuminates to notify the driver that a malfunction has occurred in the vehicle. However, the MIL will go off automatically after 3 consecutive driving cycles without the same malfunction. Immediately after the ignition switch is turned ON (ON position without starting), the MIL will illuminate continuously to indicate that the MIL is operating normally. Malfunctions with the following items illuminate the MIL
Heated Oxygen Sensor (HO2S)
Manifold Absolute Pressure Sensor (MAPS)
Throttle Position Sensor (TPS) [Built into ETC Module]
Engine Coolant Temperature Sensor (ECTS)
ETC Motor [built into ETC module]
Injectors
ECM
Refer to "DIAGNOSTIC TROUBLE CODE (DTC) CHART" for more information.
[Inspection]
After turning the ignition switch ON, make sure the indicator illuminates for about 5 seconds and then goes off.
If the lamp does not illuminate, check for an open circuit in the wiring harness, a blown fuse, or a burned-out bulb.
The ECM self-diagnosis monitors input/output signals (some signals constantly and others under specific conditions). When the ECM detects a malfunction, it stores a Diagnostic Trouble Code (DTC) and outputs a signal to the Data Link Connector. Diagnostic results can be read using the MIL or HI-SCAN (Pro). Diagnostic Trouble Codes (DTCs) remain stored in the ECM as long as battery power is maintained. However, DTCs will be erased when the battery terminal or ECM connector is disconnected, or when cleared with HI-SCAN (Pro).
If the sensor connector is disconnected while the ignition switch is ON, a Diagnostic Trouble Code (DTC) is recorded. In this case, keep the negative (-) battery terminal disconnected for 15 seconds or more to erase the diagnostic memory.
Relationship Between DTC and Driving Mode in the EOBD System
When the same malfunction is detected and stored during two consecutive driving cycles, the MIL will illuminate automatically.
The MIL automatically turns off if no malfunction is detected for 3 consecutive driving cycles.
A Diagnostic Trouble Code (DTC) is stored in the ECM memory when a malfunction is detected during two consecutive driving cycles. The MIL illuminates when the malfunction is detected in the second driving cycle. When a misfire is detected, a DTC is stored and the MIL illuminates immediately after the malfunction is detected.
The Diagnostic Trouble Code (DTC) will be automatically erased from the ECM memory if the same malfunction is not detected for 40 driving cycles.
A "warm-up cycle" means sufficient vehicle operation such that the engine coolant temperature has risen by at least 4 °C from engine start-up and reaches a minimum temperature of 71 °C.
A "driving cycle" consists of engine start-up and operation after closed-loop operation has begun.
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