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Four Wheel Drive Control System (Diagnostics - Introduction): Diagnosis Lexus IS III

Transfer Case 3 illustrations ~1677 words

PROBLEM SYMPTOMS TABLE [04/2013 - ]

HINT

  1. Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
  2. Inspect the fuses and relays related to this system before inspecting the suspected areas below.
SymptomSuspected AreaLink
Tight-corner braking phenomenon*Steering sensor circuitRefer to DTC C1297/97: Steering Angle Sensor [04/2013 - ]
Skid control ECU (Brake actuator assembly)Refer to TERMINALS OF ECU [04/2013 - ]
Transfer control solenoid circuitRefer to DTC C1298/98: Linear Solenoid Circuit [04/2013 - ]
4WD ECU assemblyRefer to TERMINALS OF ECU [04/2013 - ]
Automatic transmission with transfer assemblyRefer to COMPONENTS [04/2013 - ]
AWD warning message remains displayedAWD warning remains onRefer to AWD Warning Remains ON [04/2013 - ]
AWD warning message is not displayedAWD warning does not come onRefer to AWD Warning does not Come ON [04/2013 - ]
The system is in DTC output mode although terminals TC and CG of the DLC3 are not connectedTC and CG terminal circuitRefer to TC and CG Terminal Circuit [04/2013 - ]
The system is not in DTC output mode although terminals TC and CG of the DLC3 are connectedTC and CG terminal circuitRefer to TC and CG Terminal Circuit [04/2013 - ]
AWD warning does not come onRefer to AWD Warning does not Come ON [04/2013 - ]

HINT

*: Phenomenon of tight-corner braking

When driving in 4-wheel drive mode, the vehicle is hard to turn, as if the brakes were applied, due to the rotational difference between the front and rear tires while turning.

Scheme 5

Scheme 5: TERMINALS OF ECU [04/2013 - ]
Scheme 5: TERMINALS OF ECU [04/2013 - ]

Scheme 6

Scheme 6
Scheme 6
  1. CHECK 4WD ECU ASSEMBLY Measure the voltage and resistance of the connector. Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition A58-3 (IG1) - A58-4 (GND) G - W-B Power source voltage Engine switch on (IG) 11 to 14 V A58-2 (SLC+) - A58-1 (SLC-) B - B Transfer control solenoid signal Shift lever in D, engine idling Pulse generation (See waveform 1) A58-4 (GND) - Body ground W-B - Body ground Ground Always Below 1 ohms A58-6 (CANH) - A58-5 (CANL) W - B HIGH-level CAN bus wire - LOW-level CAN bus wire Cable disconnected from negative (-) battery terminal 54 to 69 ohms If the result is not as specified, the 4WD ECU assembly may have a malfunction. Using an oscilloscope, check the waveform 1. WAVEFORM 1 (REFERENCE) Item Content Terminal No. (Symbol) A58-2 (SLC+) - A58-1 (SLC-) Tester Range 2 V/DIV., 1 msec./DIV. Condition Shift lever in D, engine idling

Scheme 7

Scheme 7
Scheme 7
  1. DESCRIPTION Four wheel drive control system data can be read through the Data Link Connector 3 (DLC3) of the vehicle. When the system seems to be malfunctioning, use the Techstream to check for malfunctions and perform repairs. Therefore when there seems to be a problem with the four wheel drive control system, use the Techstream or SST to check and troubleshoot it.
  2. CHECK DATA LINK CONNECTOR 3 (DLC3) Inspect the battery voltage. Standard Voltage 11 to 14 V If the voltage is below 11 V, recharge the battery before proceeding. Check the DLC3. Refer to «GENERAL INFORMATION [04/2013 - ]»(ref-665529-S26412111322014102400000)
  3. FUNCTION OF AWD WARNING If a malfunction occurs during system operation, "Check AWD System" will be displayed on the multi-information display to inform the driver of the system malfunction. HINT: Check that the master warning light comes on for approximately 4 seconds.
  4. CHECK MASTER WARNING LIGHT Turn the engine switch on (IG), and check that the master warning light comes on for approximately 3 seconds. HINT: The master warning light goes off while the system is in DTC output mode.
  5. CHECK AWD WARNING Check AWD warning. Using SST, connect terminals 13 (TC) and 4 (CG) of the DLC3 (to enter DTC output mode). *a Front view of DLC3 SST: 09843-18040 Turn the engine switch on (IG). "DIAG AWD" is displayed on the multi-information display, and the 4WD ECU assembly checks the system for malfunctions. If the AWD control system is normal, "DIAG AWD FF" will be displayed on the multi-information display. If the AWD control system is not normal, "DIAG AWD XX (DTC)" will be displayed on the multi-information display. Although Test Mode is not set for the AWD control system, a message will be displayed on the multi-information display when Test Mode is activated for checking the VSC, etc. HINT: Test mode DTCs will not be stored because test mode is not set. If the systems above are not displayed on the multi-information display, there may be a malfunction in the TC and CG terminal circuit. Refer to «TC and CG Terminal Circuit [04/2013 - ]»(ref-665811-S40519879602014102400000) If the AWD warning check result is not normal, proceed to troubleshooting for the AWD warning circuit. Trouble Area See Procedure AWD warning remains on Refer to «AWD Warning Remains ON [04/2013 - ]»(ref-665811-S36106917102014102400000) AWD warning does not come on Refer to «AWD Warning does not Come ON [04/2013 - ]»(ref-665811-S42015997252014102400000)
  6. FAIL-SAFE FUNCTION If the following malfunctions occur, the 4WD ECU assembly will stop or partially change the AWD control system function. Malfunction Control Malfunction in a speed sensor System function is stopped Malfunction in the steering sensor and throttle signal line System function is partially changed

DTC CHECK/CLEAR [04/2013 - ]

  1. CHECK DTC (When Using Techstream) Check for DTCs. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Read the DTCs following the prompts on the Techstream screen. Enter the following menus: Chassis / Four Wheel Drive / Trouble Codes. Chassis > Four Wheel Drive > Trouble Codes Check the details of the DTCs. Refer to «DTC CHECK/CLEAR [04/2013 - ]»(ref-665560-S17941547592014102400000)
  2. CLEAR DTC (When Using Techstream) Clear the DTCs. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Operate the Techstream to clear the DTCs. Enter the following menus: Chassis / Four Wheel Drive / Trouble Codes. Chassis > Four Wheel Drive > Clear DTCs According to the display on the Techstream, select the trouble code data display with the clear button.
  3. CHECK DTC (When Using SST Check Wire) Check for DTCs. *a Front view of DLC3 Using SST, connect terminals TC (13) and CG (4) of the DLC3 (to enter DTC output mode). SST: 09843-18040 Turn the engine switch on (IG). Read the DTCs displayed on the multi-information display. HINT: "DIAG AWD" is displayed on the multi-information display, and the 4WD ECU assembly checks the system for malfunctions. If the AWD control system is normal, "DIAG AWD FF" will be displayed on the multi-information display (normal system code). If the AWD control system is not normal, "DIAG AWD XX (DTC)" will be displayed on the multi-information display. DTCs are explained in Diagnostic Trouble Code Chart. Refer to «DIAGNOSTIC TROUBLE CODE TABLE [04/2013 - ]»(ref-665560-S20936710382014102400000) Section Title See Procedure AWD Warning does not Come ON Refer to «AWD Warning does not Come ON [04/2013 - ]»(ref-665811-S42015997252014102400000) TC and CG Terminal Circuit Refer to «TC and CG Terminal Circuit [04/2013 - ]»(ref-665811-S40519879602014102400000)
  4. CLEAR DTC (When Using SST Check Wire) Clear the DTCs. Using SST, connect terminals 13 (TC) and 4 (CG) of the DLC3. SST: 09843-18040 Turn the engine switch on (IG). Clear the DTCs stored in the 4WD ECU assembly by depressing the brake pedal 8 times or more within 5 seconds. Check that the AWD warning (multi-information display) displays "DIAG AWD FF". Turn the engine switch off. Remove SST from the terminals of DLC3.

DATA LIST/ACTIVE TEST [04/2013 - ]

Note. In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

HINT

Using the Techstream to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

  1. DATA LIST OF 4WD ECU ASSEMBLY Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Chassis / Four Wheel Drive / Data List. According to the display on the Techstream, read the Data List. Chassis > Four Wheel Drive > Data List Tester Display Measurement Item Range Normal Condition Diagnostic Note 4WD Warning Light AWD warning (multi-information display) OFF or ON OFF: Warning off ON: Warning on - Slip Indicator Light Slip indicator light OFF or ON OFF: Indicator light OFF ON: Indicator light ON - Stop Light SW Stop light switch OFF or ON OFF: Brake pedal released ON: Brake pedal depressed - Steering Angle Value Steering angle value Min.: -3276.8° Max.: 3276.7° Left turn: Increases Right turn: Decreases Changes in proportion with the amount of steering wheel rotation during steering operation. FR Wheel Speed Front wheel speed sensor RH reading Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) No large fluctuations when driving at a constant speed. FL Wheel Speed Front wheel speed sensor LH reading Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) No large fluctuations when driving at a constant speed. RR Wheel Speed Rear wheel speed sensor RH reading Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) No large fluctuations when driving at a constant speed. RL Wheel Speed Rear wheel speed sensor LH reading Min.: 0 km/h (0 mph) Max.: 326 km/h (202 mph) Vehicle stopped: 0 km/h (0 mph) No large fluctuations when driving at a constant speed. SLC Solenoid Current SLC solenoid (transfer control solenoid) current Min.: 0 A Max.: 3 A 0 to 3 A - Number of DTC Number of DTCs recorded 0 to 255 0
  2. ACTIVE TEST OF 4WD ECU ASSEMBLY HINT: Using the Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests. Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Chassis / Four Wheel Drive / Active Test. According to the display on the Techstream, perform the Active Test. Chassis > Four Wheel Drive > Active Test Tester Display Measurement Item Control Range Diagnostic Note 4WD Warning Light AWD warning (multi-information display) Warning ON/OFF Observe the multi-information display. Slip Indicator Light Slip indicator light Indicator light ON/OFF Observe the combination meter.

DIAGNOSTIC TROUBLE CODE TABLE [04/2013 - ]

DTC No.Detection ItemWarning IndicateMemoryLink
C120C/79Linear Solenoid Power Supply System MalfunctionComes onDTC storedRefer to DTC C120C/79: Linear Solenoid Power Supply System Malfunction [04/2013 - ]
C1241/94Low Power Supply VoltageComes onDTC storedRefer to DTC C1241/94: Low Power Supply Voltage [04/2013 - ]
C1296/96ABS MalfunctionComes onDTC storedRefer to DTC C1296/96: ABS Malfunction [04/2013 - ]
C1297/97Steering Angle SensorDoes not come onDTC storedRefer to DTC C1297/97: Steering Angle Sensor [04/2013 - ]
C1298/98Linear Solenoid CircuitComes onDTC storedRefer to DTC C1298/98: Linear Solenoid Circuit [04/2013 - ]
C1299/99Cancellation of 4WD ControlComes onDTC storedRefer to DTC C1299/99: Cancellation of 4WD Control [04/2013 - ]
U0073/86Control Module Communication Bus OFFComes onDTC storedRefer to DTC U0073/86: Control Module Communication Bus OFF
U0100/85Lost Communication with ECM/PCM "A"Does not come onDTC storedRefer to DTC U0100/85: Lost Communication with ECM/PCM "A"
U0126/84Lost Communication with Steering Angle Sensor ModuleDoes not come onDTC storedRefer to DTC U0126/84: Lost Communication with Steering Angle Sensor Module
U0129/83Lost Communication with Brake System Control ModuleComes onDTC storedRefer to DTC U0129/83: Lost Communication with Brake System Control Module [04/2013 - ]

FOUR WHEEL DRIVE CONTROL SYSTEM

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