Functional Operation

Note: When main sensor malfunctions are detected by the on-board diagnostics, the vehicle is controlled using the following defaults.

Malfunctioning Item Followed by the Default Mode

Manifold Absolute Pressure Sensor
- Uses the throttle position sensor (TPS) signal and engine speed signal (crankshaft position sensor signal) to read the injector basic drive time and basic ignition timing from the preset map.
- Fixes the idle air control motor in the appointed position--so idle air control is not performed.

Intake Air Temperature Sensor
- Controls as if the intake air temperature is 45° C (113° F).

Throttle Position Sensor (TPS)
- No increase in fuel injection amount during acceleration--due to unreliable throttle position sensor signal.

Engine Coolant Temperature Sensor
- Controls as if the coolant temperature is 80° C (176° F).

Camshaft Position Sensor
- Injects fuel into the cylinders in the order 1-3-4-2 with irregular timing. (After the ignition switch is turned to ON, the No. 1 cylinder top dead center position is not detected at all.)

AC Valve Position Sensor
- Idle air control is not performed.

Heated Oxygen Sensor (front)
- Does not enter closed loop control.

Heated Oxygen Sensor (rear)
- Performs closed loop control of the air/fuel ratio by using only the front heated oxygen sensor signal.