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Cruise Control: Overview Lexus IS I

Cruise Control Systems ~761 words

DESCRIPTION & OPERATION

WARNINGVehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in appropriate AIR BAG RESTRAINT SYSTEMS article.
CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See appropriate COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

Auto Cancel Operation

If any of the following conditions are detected, the set speed is erased and the control is canceled. At this time, the power indicator will blink, and control of the system will be prohibited until the CRUISE switch is turned on again.

  1. Disconnection and/or short in the stop light switch.
  2. Failure in the vehicle speed signal.
  3. Failure in the electronic throttle parts.

If any of the following conditions are detected, the set speed is erased and the control is canceled. At this time, the power indicator will blink, and control of the system will be prohibited until the ignition switch is turned off.

  1. Failure in the stop light switch input circuit.
  2. Failure in the cancel circuit.

If any of the following conditions are detected, the set speed is erased and the control is canceled. (Reset is possible)

  1. The actual speed becomes slower than the minimum speed limit.
  2. The actual speed becomes 9.9 mph (16 km/h) slower than the set speed.

Set Operation

The actual vehicle speed is compared with the memorized vehicle speed, and when the actual vehicle speed is faster than the memorized speed, a signal is output to rotate the electronic throttle motor to close the throttle valve.

SYSTEM OPERATION CHECK

  1. Trouble shooting of a cruise control system complaint begins with verification of the customer problem. If problem occurs, go to step 3 . If problem does not occur, go to next step.
  2. If problem does not occur, review conditions under which problem occurred for customer and try to duplicate those conditions. For example, if the problem occurs on rainy days or during high humidity conditions, sprinkle water onto vehicle and see if malfunction occurs. DO NOT sprinkle water directly into engine compartment or onto electronic components. Visually inspect for signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary.
  3. Check the DTC. See «RETRIEVING DIAGNOSTIC TROUBLE CODES»(ref-154482-S05476735032003051500000) under SELF-DIAGNOSTIC SYSTEM. If there is a normal code, go to «PROBLEM SYMPTOM INDEX»(ref-154482-S11786344582003051500000) table. Perform circuit inspection and input signal check, go to steps 4 and 5 . If there is a malfunction code, go to «DIAGNOSTIC TROUBLE CODE INDEX»(ref-154482-S12815532442003051500000) table. Perform circuit inspection, go to step 4 . PROBLEM SYMPTOM INDEX Symptom Suspected Area (1) SET Not Occurring Or CANCEL Occurring (DTC Is Normal) (2) (3) (4) (5) (6) SET Not Occurring Or CANCEL Occurring (DTC Is Not Output) (6) Actual Vehicle Speed Deviates Above Or Below Set Speed (2) (6) Gear Shifting Occurs Frequently Between 3rd & O/D When Driving On Uphill Road (Hurting) (6) Cruise Control Not Cancelled, Even When Brake Pedal Is Depressed (4) (6) Cruise Control Not Cancelled, Even When Transmission Is Shifted To N Position (5) (6) Control Switch Does Not Operate (SET/COAST, ACC/RES, CANCEL Not Possible) (7) (6) SET Possible At 25 MPH (40 Km/h) Or Less, Or CANCEL Does Not Operate At 25 MPH (40 Km/h) Or Less (2) (6) Poor Response Is ACCEL & RESUME Modes (6) O/D Does Not Resume, Even Though The Road Is Not Uphill (6) DTC Memory Is Erased (6) DTC Is Not Output, Or Is Output When Should Not Be (8) (6) Cruise MAIN Indicator Light Remains ON Or Fails To Light Up (2) (6) (1) Perform test procedures in order listed under suspected area. (2) Check the input signal circuit. See «DTC P1566/54: INPUT SIGNAL CIRCUIT ABNORMAL»(ref-154482-S32379046622003051500000) under DIAGNOSTIC TESTS. (3) Check the vehicle speed sensor circuit. See «DTC P0500/21, 23: VEHICLE SPEED SENSOR MALFUNCTION»(ref-154482-S15625446452003051500000) under DIAGNOSTIC TESTS. (4) Check the stop light switch circuit. See «DTC P1520/52: STOP LIGHT SWITCH CIRCUIT MALFUNCTION»(ref-154482-S03877113102003051500000) under DIAGNOSTIC TESTS. (5) Check the park/neutral start switch circuit. See DTC P1780: PARK/NEUTRAL POSITION SWITCH under DIAGNOSTIC TESTS under «DIAGNOSIS - A-650E»(ref-140961) article under AUTOMATIC TRANSMISSION in TRANSAXLE/TRANSMISSION. (6) Check the engine control module (ECM). See «COMPUTERIZED ENGINE CONTROLS»(ref-134943-S07304048752002022100000) under SYSTEM & COMPONENT TESTING under FAULT ISOLATION in ENGINE PERFORMANCE. (7) Check the cruise control switch circuit. See «CRUISE CONTROL SWITCH CIRCUIT»(ref-154482-S18830034482003051600000) under CIRCUIT TESTS. (8) Check the diagnosis circuit.
  4. Check the cruise control circuits. See «DIAGNOSTIC TESTS»(ref-154482-S10840453752003051500000) and «CIRCUIT TESTS»(ref-154482-S12046331342003051500000) .
  5. Check the input signal. See «INPUT SIGNAL CHECK»(ref-154482-S29386683442003051500000) under SELF-DIAGNOSTIC SYSTEM.
  6. After problem has been identified and repaired, confirm repairs. See «CONFIRMATION TEST»(ref-154482-S24190480542003051500000) under SELF-DIAGNOSTIC SYSTEM.

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