Abs With Hydraulic Brake Booster Power Supply System - Diagnostics: Pre-Check

DIAGNOSIS SYSTEM
1. Check the warning lights and buzzer.
  1. Release parking brake pedal.
  2. When the ignition switch is turned ON, check that the ABS and BRAKE warning lights goes on for 3 seconds.
  3. When depressing the brake pedal repeatedly it may turn on the warning lights and buzzer.
    
    Fig 1: Locating Brake & ABS Indicator
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  HINT:
  
  If the indicator check result is not normal, proceed to troubleshooting for the ABS and BRAKE warning lights circuit (See ABS WARNING LIGHT CIRCUIT and BRAKE WARNING LIGHT CIRCUIT ).
2. In case of not using LEXUS hand-held tester:
  Check the DTC.
  1. Disconnect the short pin from DLC1.
    
    Fig 2: Locating Short Pin In DLC1 Connector
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. Using SST, connect terminals TC and E₁ of DLC1.
    SST 09843-18020
  3. Turn the ignition switch ON.
  4. Read the DTC from the ABS warning light on the combination meter.
    HINT:
    - If no code appears, inspect the diagnostic circuit or ABS warning light circuit (See TC TERMINAL CIRCUIT or ABS WARNING LIGHT CIRCUIT ).
      
      Fig 3: Identifying DLC1 Connector Terminals
      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    - As an example, the blinking patterns for normal code and codes 11 and 21 are shown.
      
      Fig 4: Identifying Blinking Patterns For Normal Code And Codes 11 And 21
      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Codes, see DIAGNOSTIC TROUBLE CODE CHART .
  6. After completing the check, disconnect terminals TC and E₁ of DLC1 and turn off the display.
    If 2 or more malfunctions are indicated at the same time the lowest numbered DTC will be displayed 1st.
3. In case of using LEXUS hand-held tester:
  Check the DTC.
  1. Hook up the LEXUS hand-held tester to the DLC3.
  2. Read the DTC by following the prompts on the tester screen.
    HINT:
    
    Refer to the LEXUS hand-held tester operator's manual for further details.
    
    Fig 5: Connecting LEXUS Hand-held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. In case of not using LEXUS hand-held tester:
  Clear the DTC.
  1. Using SST, connect terminals TC and E₁ of DLC1 and remove the short pin from DLC1.
    SST 09843-18020
  2. Turn the ignition switch ON.
  3. Clear the DTC stored in ECU by depressing the brake pedal 8 or more times within 5 seconds.
    
    Fig 6: Depressing Brake Pedal
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Check that the warning light shows the normal code.
  5. Remove the SST from the terminals of DLC1.
    SST 09843-18020
  6. Connect the short pin to DLC1.
    HINT:
    
    Disconcerting the battery cable during repairs will not erase the DTC in the ECU.
    
    Fig 7: Connecting Short Pin To DLC1
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. In case of using LEXUS hand-held tester:
  Clear the DTC.
  1. Hook up the LEXUS hand-held tester to the DLC3.
  2. Turn the ignition switch ON.
  3. Operate the LEXUS hand-held tester to erase the codes.
    (See LEXUS hand-held tester operator's manual)
    
    Fig 8: Connecting LEXUS Hand-Held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. (Reference):
  Using LEXUS break-out-box and LEXUS hand-held tester, measure the ECU terminal values.
  1. Turn the ignition switch OFF.
  2. Hook up the LEXUS break-out-box and LEXUS hand-held tester to the vehicle.
  3. Turn the ignition switch ON.
  4. Read the ECU input/output values by following the prompts on the tester screen.
    
    Fig 9: Connecting LEXUS Break-out-box & LEXUS Hand-held Tester To Vehicle
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  HINT:
  - LEXUS hand-held tester has a "Snapshot" function. This records the measured values and is effective in the diagnosis of intermittent problems.
  - Refer to the LEXUS hand-held tester/LEXUS break-out-box operator's manual for further details.
SENSOR SIGNAL CHECK (TEST MODE)
HINT:

If the ignition switch is turned from ON to ACC or LOCK during test mode, DTC will be erased.
1. In case of not using LEXUS hand-held tester:
  Check the sensor signal.
  1. Turn the ignition switch OFF.
  2. Using SST, connect terminals Ts and E₁ of DLC1.
    SST 09843-18020
  3. Start the engine.
    
    Fig 10: Identifying DLC1 Connector Terminals
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Check that the ABS warning light blinks.
    HINT:
    
    If the ABS warning light does not blink, inspect the ABS warning light circuit and Ts circuit (See ABS WARNING LIGHT CIRCUIT and TS TERMINAL CIRCUIT ).
    
    Fig 11: ABS Warning Light Blinking Pattern
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Keep the vehicle in the stationary condition on the flat place for 1 second or more.
  6. Leaving the vehicle in the stationary condition and the brake pedal in free condition for 1 second or more, continue to depress the brake pedal with 98 N (10 kgf, 22 lbf) of force or more for 1 second or more.
  7. Leaving the vehicle in the stationary condition, depress the brake pedal with 980 N (100 kgf, 221 lbf) of force or more quickly.
    HINT:
    
    At this time, the ABS warning light comes on for 3 seconds.
  8. Drive vehicle straight forward.
    When driving the vehicle with the speed faster than 45 km/h (28 mph) for several seconds, check that the ABS warning light comes off.
    
    HINT:
    
    There is a case that the sensor check is not completed if the vehicle has its rear wheels spun or its steering wheel steered during this check.
  9. Stop the vehicle.
  10. Using SST, connect terminals TC and E₁ of DLC1.
    SST 09843-18020
  11. Read the number of blinks of the ABS warning light.
    HINT:
    - See the list of DTC on step (C).
    - If every sensor is normal, a normal code is output (A cycle of 0.25 sec. ON and 0.25 sec. OFF is repeated).
    - If 2 or more malfunctions are indicated at the same time, the lowest numbered code will be displayed 1st.
  12. After doing the check, disconnect terminals of DLC1 and turn the ignition switch OFF.
    
    Fig 12: Malfunction Code Blinking Pattern
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. In case of using LEXUS hand-held tester:
  Check the sensor signal.
  1. Hook up the LEXUS hand-held tester to the DLC3.
  2. Do step (3) to (9) on the previous page.
  3. Read the DTC by following the prompts on the tester screen.
    HINT:
    
    Refer to the LEXUS hand-held tester operator's manual for further details.
    
    Fig 13: Connecting LEXUS Hand-held Tester To DLC3
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Check the DTC of the sensor function.
  
  Fig 14: Diagnostic Trouble Code Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DECELERATION SENSOR OPERATION DIAGNOSIS SYSTEM
CAUTION: While checking the deceleration sensor operating diagnosis system, ABS does not work and brake system works as a conventional brake system.

DECELERATION SENSOR CHECK

Connect 3 dry batteries of 1.5 V in series.
Connect VGS terminal to the batteries' positive (+) terminal, and GGND terminal to the batteries' negative (-) terminal, apply about 4.5 V between VGS and GGND terminals.
NOTE: Do not apply voltage of 6 V or more to terminals VGS and GGND.

Check the output voltage of GL1 and GL2 terminals.

Fig 15: Checking Output Voltage Of GL1 & GL2 Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

VOLTAGE SPECIFICATIONS

Symbols	Condition	Standard Value
GL1	Horizontal	About 2.3 V
GL1	Lean forward	0.4 V - about 2.3 V
GL1	Lean rearward	About 2.3 V - 4.1 V
GL2	Horizontal	About 2.3 V
GL2	Lean forward	About 2.3 V - 4.1 v
GL2	Lean rearward	0.4 V - about 2.3 V

HINT:

If the sensor is tilted too much it may show the wrong value.
If dropped, the sensor should be replaced with a new one.
The sensor removed from the vehicle should not be placed upside down.