FUEL SYSTEM <4D5-step
III
> - Troubleshooting
13-8
FAIL-SAFE, BACKUP FUNCTIONS
When abnormalities in the major sensors are detected by diagnosis functions, pre-set control logic operates
to maintain a safe driving condition for the vehicle.
Diagnosis item
Control features in malfunction
Accelerator pedal position sensor
D
Accelerator pedal released (idle switch ON)
Acceleration opening degree = 0 %
D
Accelerator pedal applied (idle switch OFF)
Engine controlled at low speed
Acceleration opening degree = 30 % fixed
D
Void EGR control
Idle switch
Void idling speed control.
Engine speed sensor
D
Engine controlled at low speed
D
Void EGR control
D
Void variable geometry turbocharger control
Boost air temperature sensor
D
Maintain the intake air temperature at 50
_
C.
D
Void EGR control
Vehicle speed sensor
D
Void idling speed control.
D
Void EGR control
Engine coolant temperature sensor
D
Maintain the engine coolant temperature at 80
_
C (However, the system
assumes the coolant temperature as 0
_
C when engine is started.).
D
Void EGR control
Control sleeve position sensor
D
Engine controlled at low speed
D
Void EGR control
D
Void variable geometry turbocharger control
Timer piston position sensor
D
Injection timing stabilizing control
D
Void EGR control
Barometric pressure sensor (ECU
built-in)
D
Keep the barometric pressure at 101 kPa.
D
Void EGR control
D
Void variable geometry turbocharger control
Fuel temperature sensor
Maintain the fuel temperature at 40
_
C.
Boost pressure sensor
D
Keep the boost pressure as barometric pressure (101 kPa).
D
Void EGR control
D
Void variable geometry turbocharger control
Injection volume adjusting ROM
Void correction.
GE actuator
D
Engine controlled at low speed
D
Void EGR control
D
Void variable geometry turbocharger control
Over boost
D
Void variable geometry turbocharger control
D
Engine controlled at low fuel injection
Timing control valve
D
Injection timing stabilizing control
D
Void EGR control
EGR valve position sensor
Void EGR control
Variable geometry control pressure
sensor
D
Void EGR control
D
Void variable geometry turbocharger control