TSRM/MK4 Supra/Repair Manual
Repair ManualWiring Diagrams
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Wiring Diagrams — MK4 Supra Wiring Diagrams, page 174
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7.  AUTO CANCEL FUNCTION
A)   IF ANY OF THE FOLLOWING OPERATING CONDITIONS OCCUR DURING CRUISE CONTROL OPERATION, THE SET SPEED IS ERASED, CURRENT FLOW TO MAGNETIC CLUTCH IS STOPPED AND THE CRUISE CONTROL IS RELEASED. (MAIN SW TURNS OFF).
WHEN THIS OCCURS, THE IGNITION SW MUST BE TURNED OFF ONCE BEFORE THE MAIN SW WILL TURN ON.
∗  OVER CURRENT TO TRANSISTOR DRIVING MOTOR AND/OR MAGNETIC CLUTCH.
∗  WHEN CURRENT CONTINUED TO FLOW TO THE MOTOR INSIDE THE ACTUATOR IN THE THROTTLE VALVE "OPEN" DIRECTION.
∗  OPEN CIRCUIT IN MAGNETIC CLUTCH.
∗  MOMENTARY INTERRUPTION OF VEHICLE SPEED SIGNAL.
∗  SHORT CIRCUIT IN CRUISE CONTROL SW.
∗  MOTOR DOES NOT OPERATE DESPITE THE MOTOR DRIVE SIGNAL BEING OUTPUT.
B)   IF ANY OF THE FOLLOWING CONDITIONS OCCUR DURING CRUISE CONTROL OPERATION, THE SET SPEED IS ERASED AND THE CRUISE CONTROL IS RELEASED. (THE POWER OF MAGNETIC CLUTCH IS CUT OFF UNTIL THE SET SW IS "ON" AGAIN.)
∗  WHEN THE VEHICLE SPEED FALLS BELOW THE MINIMUM SPEED LIMIT, APPROX. 40 KM/H (25 MPH)
∗  WHEN THE VEHICLE SPEED FALLS MORE THAN 16 KM/H (10 MPH) BELOW THE SET SPEED, E.G. ON AN UPWARD SLOPE.
∗  WHEN POWER TO THE CRUISE CONTROL SYSTEM IS MOMENTARILY CUT OFF.
C)   IF ANY OF THE FOLLOWING CONDITIONS OCCUR DURING CRUISE CONTROL OPERATION, THE CRUISE CONTROL IS RELEASED.
∗  OPEN CIRCUIT FOR TERMINAL 1 OF CRUISE CONTROL ECU AND TERMINAL 2 OF STOP LIGHT SW.

8.  AUTOMATIC TRANSMISSION CONTROL FUNCTION
∗  IN OVERDRIVE. IF THE VEHICLE SPEED BECOMES LOWER THAN THE OVERDRIVE CUT SPEED (SET SPEED MINUS APPROX. 4 KM/H, 2.5 MPH) DURING CRUISE CONTROL OPERATION, SUCH AS DRIVING UP A HILL, THE OVERDRIVE IS RELEASED AND THE POWER INCREASED TO PREVENT A REDUCTION IN VEHICLE SPEED.
∗  AFTER RELEASING THE OVERDRIVE, VEHICLE SPEED BECOMES HIGHER THAN THE OVERDRIVE RETURN SPEED (SET SPEED MINUS APPROX. 2 KM/H, 1.2 MPH) AND THE ECU JUDGES BY THE SIGNALS FROM POTENTIONMETER OF THE ACTUATOR THAT THE UPWARD SLOPE HAS FINISHED, OVERDRIVE IS RESUMED AFTER APPROXIMATELY 2 SECONDS.
∗  DURING CRUISE CONTROL DRIVING, THE CRUISE CONTROL OPERATION SIGNAL IS OUTPUT FROM THE CRUISE CONTROL ECU TO THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU). UPON RECEIVING THIS SIGNAL, THE ENGINE CONTROL MODULE (ENGINE AND ELECTRONICALLY CONTROLLED TRANSMISSION ECU) CHANGES THE SHIFT PATTERN TO NORMAL.
TO MAINTAIN SMOOTH CRUISE CONTROL OPERATION (ON A DOWNWARD SLOPE ETC.), LOCK–UP RELEASE OF THE TRANSMISSION WHEN THE IDLING POINT OF THE THROTTLE POSITION IS "ON" IS FORBIDDEN.

——  SERVICE HINTS  ——
C 4  CRUISE CONTROL ACTUATOR
 1–3  :  APPROX. 2 K
 5–4  :  APPROX. 38.5
C14  CRUISE CONTROL SW [COMB.SW]
 15–17  :  CONTINUOUS WITH MAIN SW ON
   5–17  :  APPROX. 418    WITH CANCEL SW ON
           :  APPROX. 68    WITH RESUME/ACCEL SW ON
           :  APPROX. 198    WITH SET/COAST SW ON
C16  CRUISE CONTROL ECU
    14–GROUND  :  APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
 1, 15–GROUND  :  ALWAYS APPROX. 12 VOLTS
      3–GROUND  :  CONTINUOUS WITH PARKING BRAKE LEVER PULLED UP (ONE OF THE CANCEL SW)
    20–GROUND  :  4 PULSE WITH 1 ROTATION OF ROTOR SHAFT
    18–GROUND  :  APPROX. 418    WITH CANCEL SW ON IN CONTROL SW
                   : APPROX. 198    WITH SET/COAST SW ON IN CONTROL SW
                   : APPROX. 68    WITH RESUME/ACCEL SW ON IN CONTROL SW
    13–GROUND  :  ALWAYS CONTINUOUS

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