Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fail-safe Chart
When the DTC listed below is detected, the ECM enters fail-safe mode and the MIL illuminates.
| DTC No. | Detected items | Engine operating condition in fail-safe mode | |
|---|---|---|---|
| P0101 P0102 P0103 |
Mass air flow sensor circuit | Engine speed will not rise more than 2, 400 rpm due to the fuel cut. | |
| P0117 P0118 |
Engine coolant temperature sensor circuit | Engine coolant temperature will be determined by ECM based on the following condition. CONSULT displays the engine coolant temperature decided by ECM. |
|
| Condition | Engine coolant temperature decided (CONSULT display) | ||
| Just as ignition switch is turned ON or START | 40°C (104°F) | ||
| Approx. 4 minutes or more after engine starting | 80°C (176°F) | ||
| Except as shown above | 40 - 80°C (104 - 176°F) (Depends on the time) | ||
| When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates while engine is running. | |||
| P0122 P0123 P0222 P0223 P2135 |
Throttle position sensor | The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10 degrees. The ECM regulates the opening speed of the throttle valve to be slower than the normal condition. So, the acceleration will be poor. |
|
| P0500 | Vehicle speed sensor | When the fail-safe system for vehicle speed sensor is activated, the cooling fan operates (Highest) while engine is running. | |
| P0643 | Sensor power supply | ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring. | |
| P2100 P2103 |
Throttle control relay | ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring. | |
| P2101 | Electric throttle control function | ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring. | |
| P2118 | Throttle control motor | ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring. | |
| P2119 | Electric throttle control actuator | (When electric throttle control actuator does not function properly due to the return spring malfunction:) ECM controls the electric throttle actuator by regulating the throttle opening around the idle position. The engine speed will not rise more than 2, 000 rpm. |
|
| (When throttle valve opening angle in fail-safe mode is not in specified range:) ECM controls the electric throttle control actuator by regulating the throttle opening to 20 degrees or less. |
|||
| (When ECM detects the throttle valve is stuck open:) While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops, the engine stalls. The engine can restart in N or P (CVT), Neutral (M/T) position, and engine speed will not exceed 1, 000 rpm or more. |
|||
| P2122 P2123 P2127 P2128 P2138 |
Accelerator pedal position sensor | The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10 degrees. The ECM regulates the opening speed of the throttle valve to be slower than the normal condition. So, the acceleration will be poor. |
|
- When there is an open circuit on MIL circuit, the ECM cannot warn the driver by illuminating MIL when there is malfunction on engine control system.
Therefore, when electrical controlled throttle and part of ECM related diagnoses are continuously detected as NG for 5 trips, ECM warns the driver that engine control system malfunctions and MIL circuit is open by means of operating fail-safe function.
The fail-safe function also operates when above diagnoses except MIL circuit are detected and demands the driver to repair the malfunction.
| Engine operating condition in fail-safe mode | Engine speed will not rise more than 2, 500 rpm due to the fuel cut |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.