Fail-Safe Sensor Malfunctions

CAMSHAFT POSITION SENSOR MALFUNCTION
The fail-safe mode operation starts immediately after all of the following conditions have been satisfied for several seconds.

- No pulse of 120° signal (reference signal) detected for several seconds, or 1° signal (position signal) is equivalent to 0 rpm.
- Ignition switch in "START".
- Battery positive voltage is greater than 10 volts with ignition switch "ON".
- The park/neutral position switch is "ON", or the inhibitor switch is in the "P" or "N" position.
- When ignition switch is in "START", battery positive voltage is at least 1 volt lower than when ignition switch is "ON".

MASS AIR FLOW SENSOR MALFUNCTION
If the Mass Air Flow (MAF) Sensor output voltage is below the specified value, the Engine Control Module (ECM) senses an mass air flow sensor malfunction. In case of a malfunction, the throttle position sensor substitutes for the mass air flow sensor.

Though the mass air flow sensor is malfunctioning, it is possible to start the engine and drive the vehicle. However, engine speed will not rise more than 2,000 rpm in order to inform the driver of fail-safe system operation while driving.

ENGINE COOLANT TEMPERATURE SENSOR MALFUNCTION
When Engine Coolant Temperature Sensor (ECT) output voltage is below or above the specified value, water temperature is fixed at the preset value as follows:

Condition Engine coolant temperature decided
Just as ignition switch is 20°C (68°F)
turned ON or Start
More than 6 minutes after 80°C (76°F)
ignition ON or Start
Except as shown above 20-80°C (68-176°F) (Depends on the time)

KNOCK SENSOR MALFUNCTION
When the output signal of the Knock Sensor (KS) is abnormal, the ECM judges it to be malfunctioning. When knock sensor is malfunctioning, ignition timing will retard according to operating conditions.

THROTTLE POSITION SENSOR MALFUNCTION
When the output signal of the Throttle Position Sensor (TPS) is abnormal, the ECM judges it as a malfunctioning of the throttle position sensor. The ECM does not use the throttle position sensor signal but uses a closed throttle position switch signal.