Cruise Control: Overview Lexus SC II рестайлинг

SYSTEM DESCRIPTION

1. CRUISE CONTROL SYSTEM DESCRIPTION The cruise control system is controlled by the ECM, and is activated by the throttle position sensor and motor. The ECM controls the following functions: ON-OFF, -/ SET, +/RES, CANCEL, vehicle speed operation, motor output control, and overdrive control. The ECM compares the speed sensor vehicle speed with the stored vehicle speed set through the cruise control main switch. The ECM instructs the throttle valve motor of the throttle position sensor to close the valve when the driving vehicle speed is greater than the stored vehicle speed, and instructs it to open the valve when the driving speed is less than the stored speed. The ECM receives signals such as ON-OFF, -/SET, +/ RES, and CANCEL from the cruise control main switch and executes them. The ECM illuminates the combination meter's CRUISE main indicator light when it receives the cruise control main switch ON signal. The ECM cancels the cruise control system when the brake pedal is depressed and the ECM receives the stop light switch signal. (The set speed is stored in memory.) The ECM cancels the cruise control system when moving the shift lever to any position other than D, or during sequential shift mode, the shift lever is moved from S (4) to "-" (3, 2, 1) and the ECM receives the PNP switch signal.
2. LIMIT CONTROL Low speed limit The lowest possible limit of the speed setting range is set at approximately 40 km/h (25 mph). The cruise control system cannot be set when the vehicle speed is below the low speed limit. Cruise control operation will be automatically canceled and the set speed is stored in memory when the vehicle speed decreases below the low speed limit while the cruise control system is operating. High speed limit The highest possible limit of the speed setting range is set at approximately 200 km/h (125 mph). The cruise control system cannot be set when the vehicle speed is over the high speed limit. Also, +/ RES cannot be used to increase speed beyond the high speed limit.
3. OPERATION OF CRUISE CONTROL The cruise control main switch operates 7 functions: SET, COAST, TAP-DOWN, RESUME, ACCEL, TAP-UP, and CANCEL. The SET, TAP-DOWN and COAST functions, and the RESUME, TAP-UP and ACCEL functions are operated with the same switch. The cruise control main switch is an automatic return type switch which turns on only while pressing it in each arrow direction and turns off after releasing it. SET control Vehicle speed is stored and constant speed control is maintained when setting the switch to -/SET while driving with the cruise control main switch ON (the CRUISE main indicator light is illuminated), and the vehicle speed is within the set speed range (between the low and high speed limits). COAST control The ECM changes the cruise control demanding throttle opening angle to 0° and decelerates the vehicle when -/SET on the cruise control main switch is pressed and held while the cruise control system is operating. When the cruise control main switch is released from -/SET, the vehicle speed is stored and constant speed control is maintained. HINT: The throttle valve is not fully closed due to idle speed control, etc. TAP-DOWN control When tapping down on the cruise control main switch to -/SET (for approximately. 0.6 seconds) while the cruise control system is operating, the stored vehicle speed decreases each time by approximately 1.6 km/h (1.0 mph). When the cruise control main switch is released from -/SET and the difference between the driving and stored vehicle speed is more than 5 km/h (3 mph), the vehicle speed is stored and constant speed is maintained. ACCEL control The throttle valve motor of the throttle position sensor and motor is instructed by the ECM to open the valve when +/RES on the cruise control main switch is pressed and held while the cruise control system is operating. When the cruise control main switch is released from +/RES, the vehicle speed is stored and constant speed is maintained. TAP-UP control When tapping up on the cruise control main switch to +/RES (for approximately 0.6 seconds) while the cruise control system is operating, the stored vehicle speed increases each time by approximately 1.6 km/h (1.0 mph). However, when the difference between the driving and the stored vehicle speed is more than 5 km/h (3 mph), the stored vehicle speed does not change. RESUME control If the cruise control operation was canceled* and if the driving speed is within the set speed range, setting the cruise control main switch to +/RES restores the vehicle speed memorized at the time of cancellation, and constant speed is maintained. HINT: *: The cruise control operation can be canceled through one of the following methods: by operating the stop light switch or CANCEL switch; moving the shift lever from D to N; or, in sequential shift mode, moving the shift lever from S (4) to "-" (3, 2, 1). CANCEL control Manual cancel Performing any of the following cancels the cruise control system (the stored vehicle speed in the ECM is maintained). Depressing the brake pedal Moving the shift lever to any position other than D, during sequential shift mode from S (4) to "-" (3, 2, 1) Pushing the cruise control main switch to CANCEL Turning the cruise control main switch OFF (set speed is not stored in memory). Auto cancel If any of the conditions below are met, the cruise control operation is canceled. Vehicle speed decreases to less than the low speed limit (the set speed is not erased; it is possible to reset or resume speed). While operating the cruise control during driving, if the VSC operates, the cruise control operation is canceled (the set speed is stored in memory). Vehicle speed is 16 km/h (10 mph) less than the set speed (set speed is erased)

DESCRIPTION

Vehicle speed sensor signal circuit is abnormal, the set speed is erased and the cruise control operation is canceled. At this time, the power indicator blinks until the main switch is pushed OFF. Cruise control operation is prohibited until the main switch is pushed ON again.

DTC DETECTION CONDITION CHART

While driving with cruise control, if the ECM detects that the brake pedal is depressed, the cruise control system will cancel. The stop light switch sends brake pedal status signals to the ECM.

When the brake pedal is not depressed, terminal ST1- is equal to the positive (+) battery voltage and terminal STP is below 1 V. When the brake pedal is depressed, the ECM cancels cruise control operation.

The ECM outputs this DTC when the voltage of terminals ST1- and STP are both below 1 V for 0.5 seconds or more at the same time.

At this time, the set speed is erased, the cruise control operation is canceled, and the power indicator blinks until the main switch is pushed OFF. Cruise control operation is prohibited until the main switch is pushed ON again.

DTC DETECTION CONDITION CHART

Stop Light Switch Circuit Malfunction - Wiring Diagram. Scheme 3

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Scheme 7

1. READ VALUE OF DATA LIST (STOP LIGHT SWITCH) Check the DATA LIST for proper functioning of the stop light switch. ECM (cruise control) ITEM MEASUREMENT NORMAL CONDITION CHART Item Measurement Item / Display (Range) Normal Condition Diagnostic Note STP LIGHT SW M Stop light switch signal (Main CPU) / ON or OFF ON: Brake pedal is depressed OFF: Brake pedal is released - STP LIGHT SW S2 Stop light switch signal (Sub CPU / ON or OFF ON: Brake pedal is depressed OFF: Brake pedal is released - STP LIGHT SW S1 Stop light switch signal (Sub CPU) / ON or OFF ON: Brake pedal is depressed OFF: Brake pedal is released - OK: OK: Display changes according to brake pedal operation described in above table. HINT: Stop light SW S1 has a function to disconnect the connection (OFF) when the pedal is depressed. However, the intelligent tester displays ON, as the ECM performs control using reverse logic. Stop light SW S1 indicates the input of ST1 - terminal, and stop light SW S2 indicates the input of STP terminal. OK: REPLACE ECM NG: Go to next step
2. INSPECT STOP LIGHT SWITCH ASSEMBLY Disconnect the stop light switch connector. Measure the resistance of the switch. Standard voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Switch Condition Specified Condition 1 - 2 Pin not pushed (Brake pedal depressed) Below 1 ohms 3 - 4 Pin not pushed (Brake pedal depressed) 10 kohms or higher 1 - 2 Pin pushed (Brake pedal released) 10 kohms or higher 3 - 4 Pin pushed (Brake pedal released) Below 1 ohms NG: REPLACE STOP LIGHT SWITCH (Scheme 4): Inspecting Stop Light Switch Assembly OK: Go to next step
3. CHECK WIRE HARNESS (ECM - BODY GROUND) Disconnect the E5 and E6 ECM connectors. Turn the ignition switch ON. Measure the voltage of the wire harness side connectors. Standard voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Brake Pedal Condition Specified Condition E5-4 (STP) - Body ground Depressed 10 to 14 V E5-4 (STP) - Body ground Released Below 1 V E6-8 (ST1-) - Body ground Depressed Below 1 V E6-8 (ST1-) - Body ground Released 10 to 14 V Result RESULT REFERENCE CHART Result Proceed to OK A NG (STP terminal is NG) B NG (ST1 - terminal is NG) C A: REPLACE ECM C: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 5): Disconnecting E5 And E6 ECM Connectors B: Go to next step
4. INSPECT FUSE (STOP) Remove the STOP fuse from the driver side junction block ECU. Measure the resistance of the fuse. Standard resistance: Below 1 ohms NG: REPLACE FUSE OK: Go to next step
5. CHECK WIRE HARNESS (MAIN BODY ECU - BATTERY) Disconnect the D2 ECU connector. Measure the voltage of the wire harness side connector. Standard voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Brake Pedal Condition Specified Condition D2-13 (STPI) - Body ground Depressed 10 to 14 V D2-13 (STPI) - Body ground Released Below 1 V NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 6): Identifying D2 Wire Harness Side Connector Terminals OK: Go to next step
6. CHECK MAIN BODY ECU (for Driver Side) Reconnect the D2 ECU connector. Measure the voltage according to the value(s) in the table below. (Scheme 7): Identifying D2 Driver Side Junction Block Connector Terminals Standard voltage TESTER CONNECTION SPECIFIED CONDITION Tester Connection Brake Pedal Condition Specified Condition D2-12 (STPO) - Body ground Depressed 10 to 14 V D2-12 (STPO) - Body ground Released Below 1 V NG: REPLACE MAIN BODY ECU (for Driver Side) OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (MAIN BODY ECU - ECM)

This DTC indicates the internal abnormalities of the ECM.

DTC DETECTION CONDITION CHART

HINT

The ECM receives signals from each sensor to control all the functions of the cruise control with the microcomputer. When a trouble code is detected, fail-safe remains on until the ignition switch is turned OFF.

This circuit sends signals to the ECM depending on the cruise control main switch condition.

The battery supplies positive (+) battery voltage to the cruise control main switch. Then terminal CCS of the ECM receives the voltage according to the switch condition.

Scheme 8

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Scheme 10

1. READ VALUE OF DATA LIST (CRUISE CONTROL MAIN SWITCH) Check the DATA LIST for proper functioning of the cruise control main switch. ECM (cruise control) ITEM MEASUREMENT NORMAL CONDITION CHART Item Measurement Item / Display (Range) Normal Condition Diagnostic Note MAIN SW (SUB) Cruise main switch signal (Sub CPU) / ON or OFF ON: Cruise control main switch is ON (Sub CPU) OFF: Cruise control main switch is OFF (Sub CPU) - MAIN SW (MAIN) Cruise main switch signal (Main CPU) / ON or OFF ON: Cruise control main switch is ON (Main CPU) OFF: Cruise control main switch is OFF (Main CPU) - CANCEL SW CANCEL switch signal / ON or OFF ON: CANCEL switch ON OFF: CANCEL switch OFF - SET/COAST SW -/SET switch signal / ON or OFF ON: -/SET switch ON OFF: -/SET switch OFF - RES/ACC SW +/RES switch signal/ ON or OFF ON: +/RES switch ON OFF: +/RES switch OFF - OK: When cruise control main switch operation is performed, the results will be same as above. OK: REPLACE ECM NG: Go to next step
2. INSPECT CRUISE CONTROL MAIN SWITCH (Scheme 8): Inspecting Cruise Control Main Switch Measure the resistance of the switch. Standard resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Switch Condition Specified Condition 3 (ECC) - 2 (CCS) +/RES 216 to 264 ohms 3 (ECC) - 2 (CCS) -/SET 567 to 693 ohms 3 (ECC) - 2 (CCS) CANCEL 1386 to 1694 ohms 3 (ECC) - 2 (CCS) Main switch OFF 10 kohms or higher 3 (ECC) - 2 (CCS) Main switch ON Below 1 ohms NG: REPLACE CRUISE CONTROL MAIN SWITCH OK: Go to next step
3. INSPECT SPIRAL CABLE SUB-ASSEMBLY Measure the resistance of the spiral cable. Standard resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition C10-2 (CCS) - A-2 (CCS) Below 1 ohms C10-3 (ECC) - A-3 (ECC) Below 1 ohms NG: REPLACE SPIRAL CABLE SUB-ASSEMBLY (Scheme 9): Identifying C10 Spiral Cable Sub-Assembly Connector Terminals OK: Go to next step
4. CHECK WIRE HARNESS (SPIRAL CABLE - ECM AND BODY GROUND) Disconnect the E5 ECM connector. Disconnect the C10 spiral cable connector. Measure the resistance of the wire harness side connectors. Standard resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition E5-31 (CCS) - C10-2 (CCS) Below 1ohms E5-31 (CCS) - Body ground 10 kohms or higher C10-2 (CCS) - Body ground 10 kohms or higher C10-3 (ECC) - Body ground Below 1ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 10): Disconnecting E5 ECM Connector OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE (See «PROBLEM SYMPTOMS TABLE» )

The ECM detects a cruise control main switch signal and sends it to the combination meter through multiplex communication system (BEAN). Then the CRUISE main indicator light comes on.

Connecting terminals TC and CG of the DLC3 enables DTCs to be read through blinking patterns of the combination meter's CRUISE main indicator light.

HINT

When a warning light of the combination meter stays blinking, terminal TC of the DLC3 or an ECU may have a ground short.

TC And TG Terminals - Wiring Diagram. Scheme 11

Scheme 12

1. CHECK WIRE HARNESS (DLC3 - ECM AND BODY GROUND) Disconnect the E5 ECM connector. Measure the resistance of the wire harness side connectors. Standard resistance TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition D1-13 (TC) - E5-3 (TC) Below 1 ohms D1-13 (TC) - Body ground 10 kohms or higher D1-4 (CG) - Body ground Below 1 ohms NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (Scheme 12): Disconnecting E5 ECM Connector OK: REPLACE ECM

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1. DISCONNECT CABLE FROM NEGATIVE BATTERY TERMINAL CAUTION: Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to prevent airbag and seat belt pretensioner activation.
2. REMOVE NO. 2 STEERING WHEEL COVER LOWER
3. REMOVE SWITCH AND VOLUME CASE Apply protective tape to the steering wheel boss cover lower as shown in the illustration. Using a screwdriver, detach the 3 claws and remove the case. HINT: Tape the screwdriver tip before use. (Scheme 13): Applying Protective Tape To Steering Wheel Boss Cover Lower
4. REMOVE STEERING PAD SWITCH MODULATOR Remove the 2 screws. Remove the modulator and then disconnect the connector.
5. REMOVE STEERING PAD ASSEMBLY (See «INSTALLATION» )
6. REMOVE STEERING WHEEL ASSEMBLY (See «REMOVAL» ) (Scheme 14): Identifying Steering Pad Switch Modulator
7. REMOVE CRUISE CONTROL MAIN SWITCH ASSEMBLY Remove the 3 screws. (Scheme 15): Locating Cruise Control Main Switch Assembly Screws Reverse the steering wheel and remove the 3 screws. Remove the steering wheel boss cover lower and switch. (Scheme 16): Locating Steering Wheel Bolt

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Scheme 20

1. INSTALL CRUISE CONTROL MAIN SWITCH ASSEMBLY Install the switch and steering wheel boss cover lower. Install the 3 screws. (Scheme 17): Locating Switch And Steering Wheel Boss Cover Lower Screws Install the 3 screws.
2. INSTALL STEERING WHEEL ASSEMBLY (See «INSTALLATION» )
3. INSTALL STEERING PAD ASSEMBLY (See «DISPOSAL» ) (Scheme 18): Locating Steering Wheel Assembly
4. INSTALL STEERING PAD SWITCH MODULATOR Install the modulator and then connect the connector. Install the 2 screws. (Scheme 19): Locating Steering Pad Switch Modulator Screws
5. INSTALL SWITCH AND VOLUME CASE Attach the 3 claws to install the case.
6. INSTALL NO. 2 STEERING WHEEL COVER LOWER
7. CONNECT CABLE TO NEGATIVE BATTERY TERMINAL
8. PERFORM INITIALIZATION Perform initialization (see «INITIALIZATION» ). NOTE: Certain systems need to be initialized after disconnecting and reconnecting the cable from the negative (-) battery terminal.
9. CHECK SRS WARNING LIGHT Check the SRS warning light (see «DIAGNOSIS SYSTEM» ). (Scheme 20): Applying Protective Tape

See also:
• DTC P0705 TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT); DTC P0850 PARK / NEUTRAL SWITCH INPUT CIRCUIT
• DTC P0500 VEHICLE SPEED SENSOR "A"; DTC P0503 VEHICLE SPEED SENSOR "A" INTERMITTENT / ERRATIC / HIGH