Vehicle Stability Control System (For Vacuum Brake Booster) Check For Intermittent Problems

  1. CHECK FOR INTERMITTENT PROBLEMS

Vehicle Stability Control System (For Vacuum Brake Booster) -- Check For Intermittent Problems



CHECK FOR INTERMITTENT PROBLEMS
HINT:
A momentary interruption (open circuit) in the connectors and/or wire harnesses between the sensors and ECUs can be detected using the ECU Data List function of the intelligent tester.

  1. Turn the ignition switch off.

  2. Connect the intelligent tester to the DLC3.

  3. Turn the ignition switch to ON.

  4. Turn the intelligent tester on.

  5. Enter the following menus: Chassis / ABS/VSC/TRC / Data List.

  6. Select areas where momentary interruptions should be monitored.

    HINT:
    1. A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is turned to ON (initial check).
    2. If Error is displayed, measure the resistance between the ECUs and sensors or between ECUs.
    3. Error remains displayed on the intelligent tester for 1 second after the harness signal changes from a momentary interruption (open circuit) to normal.

    ABS/VSC/TRC
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    FR Speed Open
    		Front speed sensor RH open circuit detection/ Error or Normal
    		Normal
    		-
    FL Speed Open
    		Front speed sensor LH open circuit detection/ Error or Normal
    		Normal
    		-
    RR Speed Open
    		Rear speed sensor RH open circuit detection/ Error or Normal
    		Normal
    		-
    RL Speed Open
    		Rear speed sensor LH open circuit detection/ Error or Normal
    		Normal
    		-
    EFI Communication Open
    		ECM communication open circuit detection/ Error or Normal
    		Normal
    		-
    Yaw Rate Open
    		Yaw rate sensor open circuit detection/ Error or Normal
    		Normal
    		-
    Deceleration Open
    		Acceleration sensor open circuit detection/ Error or Normal
    		Normal
    		-
    Steering Open
    		Steering angle sensor open circuit detection/ Error or Normal
    		Normal
    		-
    Master Cylinder Open
    		Master cylinder pressure sensor open circuit detection/ Error or Normal
    		Normal
    		-
    IG Voltage Value Decreased
    		IG voltage value decrease detection/ Error or Normal
    		Normal
    		-
    IG Voltage Value Increased
    		IG voltage value increase detection/ Error or Normal
    		Normal
    		-
    FR Speed Sensor Voltage Open
    		Front speed sensor RH voltage open circuit detection/ Error or Normal
    		Normal
    		-
    FL Speed Sensor Voltage Open
    		Front speed sensor LH voltage open circuit detection/ Error or Normal
    		Normal
    		-
    RR Speed Sensor Voltage Open
    		Rear speed sensor RH voltage open circuit detection/ Error or Normal
    		Normal
    		-
    RL Speed Sensor Voltage Open
    		Rear speed sensor LH voltage open circuit detection/ Error or Normal
    		Normal
    		-
    M/C Pressure Sensor Noise
    		Master cylinder pressure sensor noise detection/ Error or Normal
    		Normal
    		-
    Brake Pedal Switch Open
    		Brake pedal load sensing switch open circuit detection/ Error or Normal
    		Normal
    		-
    Yaw Rate Sensor Voltage Open
    		Yaw rate sensor voltage open circuit detection/ Error or Normal
    		Normal
    		-
    EFI Communication Invalid
    		ECM communication invalid detection/ Error or Normal
    		Normal
    		-

  7. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors or between ECUs.

    OK:
    Normal display does not change.
    HINT:
    If the display changes, the connector and/or the wire harness has caused a momentary interruption of the circuit. Repair or replace the connector and/or wire harness as one of them is faulty.