V6 Engine AJ-V6/AJ28
28¥ Limp home mode in which a high idle speed
is set, with no accelerator pedal response, to
allow the vehicle to creep: the RED warning
light and FAIL SAFE ENGINE MODE message
are activated: this mode is set by, eg the loss
of two or more sensors.
¥ Engine shutdown due to serious throttle
malfunction.
J.303.1363
THROTTLE CONTROL SYSTEM
System Monitoring
Within the PCM, operation of the overall throttle
control system (main processor logic and
software) is itself monitored by a separate,
independent microprocessor, the electronic
throttle monitor. Communication is maintained
between the two processors but if it is lost or if
faults are detected by the monitor (eg throttle
angle greater than demanded), the monitor
processor may call for a restricted operating mode
such as cruise cancellation or a forced idle
condition or engine shutdown.
Failure Modes
There are four failure modes:
¥ Loss of redundancy eg a failure of one sensor
output: this type of fault causes the AMBER
warning light to illuminate and FAIL SAFE
ENGINE MODE to be displayed on the
message centre (the engine remains fully
functional).
¥ Cruise inhibit.
J.303.1363
PCM
Electronic
Throttle
Monitor
Main
Processor
SystemTAC
Module
Motor
Electronic Throttle
TP Sensor
Command 1
Command 2
SCP
APP
Sensor
Motor Winding 1
Motor Winding 2
To the TP Sensor
APP1
APP2
APP3
5V
5V
5V
5V
5V
12V
12V
TP1
TP2
TP3
Inductive
Position
Encoder
