Subaru 2002 Impreza Service Manual page 479

CRUISE CONTROL
Cruise Control System
M: FAIL-SAFE FUNCTION
The cruise control system has a fail-safe function that cancels the cruise control operation when
any of the following conditions occurs.
1. CONFLICT BETWEEN CRUISE CONTROL SWITCHES AND CANCELLATION SIGNAL
GENERATING SWITCHES
1) The cruise control system is deactivated if any of the cruise control switches (SET/COAST, RE-
SUME/ACCEL, and CANCEL switches) is turned ON while any of the cancellation signal generat-
ing switches (brake, stop lamp, clutch, and inhibitor switches) is being operated. The system is
re-activated when the cruise control switch is turned OFF and then turn ON again after the can-
cellation signal generating switch has been returned to its released position.
2) The cruise control system becomes deactivated if the ignition switch is turned ON with any of
the cruise control switches (including the main switch) in the ON position. The system deactivating
function is retained until the main switch is turned OFF.
2. ABNORMALITIES IN ELECTRIC CIRCUITS
The cruise control system is deactivated and the set speed is also canceled if any of the following
abnormalities occurs in the system's electric circuits.
The system deactivation function is retained until the ignition switch is turned OFF.
1) The stepping motor terminal is grounded; or the stepping motor drive circuit is broken due to
a short- or open-circuit.
2) The stepping motor clutch drive circuit is shorted.
3) Vehicle speed variation in a 350 ms period exceeds flOkm/h.
4) Fusion has occurred in an internal relay and is detected while the vehicle is running with the
cruise control deactivated.
5) The cruise control module becomes inoperative or its operation is faulty.
6) There is discrepancy between the values stored in the two RAMS of the control module.
7) An abnormality is detected as a result of the self-diagnosis performed after turning ON of the
ignition switch.
3. ABNORMALITIES IN STEPPING MOTOR
The cruise control system is deactivated if either of the following abnormalities occurs in the step-
ping motor.
1) The stepping motor does not operate properly.
2) The stepping motor is energized for unduly long period and too frequently.
When the system is deactivated, it cannot be reactivated for 2
-
20 minutes after detection of the
abnormal condition.
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