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Watch the pulse with the LEDs.
All automotive signals are displayed effectively on nine LEDs.

Completely safe for even the most sensitive components.
The state-of-the-art technology used in the Gautoprobe, lets you work safely with all sensors and car ECUs.

One simple test for checking all circuits.
The powerful logic probe can check for open circuits, short circuits and other defective electrical connections.

Voltage, Frequency or duty modes.
You can alternate between voltage, frequency or duty modes at the push of a button while the Gautoprobe is in use.

 ■  Application

1. Starting & Charging System                   3. Sensors

         ■ Starter Motor                                                              ■ Power & Ground of Sensors             

             Test Battery Load                                       MAP Sensor

          Alternator Capacitor                                    OSensor

          Test Charging Signal                                   RPM Sensor

                                                                           Air Flow Sensor

        2. Electric Relay & Actuator                                Crank Angle Sensor

             Window Motor                                           Vehicle Speed Sensor

          WindShield Wiper Motor                              No.1 TDC Sensor

          Door Lock Actuator                                     Water Temperature Switch

          Trunk Lock                                                Pulse Generator(A/T)

          Fuel Pump Motor                                  Idle Switch

          Stepping Motor                                          ABS-Wheel Speed Sensor

            ISA(Idle Speed Actuator)                              Throttle Position Sensor

            TR(Power Transistor)                                   Cam Position Sensor

          Fuel Injector                                              Noise Filter   

                                                                                                                         ■ Main Control Relay                                   

                                                                                                                         ■ Air Temperature Sensor

                                                              Barometric Pressure Sensor

                                                              Solenoid Valve(A/T)

                                                              Electric Horn

                                                                            Electric Fan Switch



   Technical Data 


Product Name: Multi Logic Probe “Gautoprobe” 

Model No.: T-7205J 

Controller Type: Digital/ LED Micom 

CPU: 8Bit Micom, 10 Bit A/D Converter; 10~20 MHz Clock Speed 

Display: 3 Digit FND; 9 Color LED 

Display Voltage Range: DC -45 Vd.c. ~ +50 Vd.c.

Frequency : 0~20 KHz 

Maximum Voltage : ± 50 Vd.c.,  30 Va.c.

        Maximum Transient Overvoltage : 500 Vpeak

Electrical Properties:   Standby Current: 49±5 uA

Normal Current: 65mA±5 mA 

Voltage Test Current: 180mA±10 mA 

Frequency Test Current: 170mA±10 mA 

Illumination Current: 50mA±5 mA 

        Impedance : 220k±10 k

        Minimum Source Current : 220uA

Effective Temperature Range: 0 ~ 50 

Power Requirements: DC 3V, LR03 (AAA 1.5V Alkaline) 2EA 

Illumination: White LED 

Size: 201×34×25 mm (Including Probe Pin) 

Weight: 70 g 

Included Accessories: Ground Clip; Extension Probe 


  ■ Description

   User Guide

1. How to connect the Ground Lead 

Connect the black ground lead to the end of the Gautoprobe in order to check  Voltage, Frequency and Pulse modes. 


2. How to check the Probe and Ground Clip 

  1) Connect black ground lead to the end of the Gautoprobe. 

  2) Push power switch to turn on the Gautoprobe. 

3) Touch probe to the ground clip. You should see the blue light on the bottom LED turn on, and the display screen will change 

    from '---' to '0.0'. 

4) When leads are not touching, all LED lamps should be off and the display screen should indicate '---'. 

5) Except for the above descriptions,  if other LEDs are displayed during startup, the test leads must be replaced before using the Gautoprobe. Failure to do so could result in damage to the equipment or electric shock. 


3. How to use the buttons 

    1) Power Button: Press the Power button once to turn on the Gautoprobe. Press again to turn off. 

    2) Voltage Mode: When the Gautoprobe is turned on, the ‘V’ lamp  automatically turns on. 

    3) Stand-by Mode: When the Gautoprobe remains in voltage mode, but is not used for 3 minutes, all LED lamps automatically turn off, with the screen displaying ‘---’. 

  4) Illumination Button: Press the Light button to turn on flashlight.

  5) Select Button: Press the Change button to toggle between ‘V', ‘Hz’, and ‘%’ modes



4. How to operate Modes


 1) Voltage Mode: The three LED lamps indicate voltage; 

     the 9 different colors represent 9 levels of voltage. 

     This wide range of LED colors is the most important

      feature of the Gautoprobe. 

 Bottom Lamp (Voltage range: 0.0 V ~ 2.5 V)  

 When the measured value is between 0.0 V and 0.5 V, 

 the bottom LED will turn blue. 

 When the measured value is between 0.6 V and 1.2 V, 

 the bottom LED will turn orange. 

 When the measured value is between 1.3 V and 2.5 V, 

  the bottom LED will turn red. 


 Middle Lamp (Voltage range: 2.6 V ~ 9.2 V) 

 When the measured value is between 2.6 V and 4.0 V, 

 the middle LED will turn blue. 

 When the measured value is between 4.1 V and 6.0 V, 

the middle LED will turn orange. 

 When the measured value is between 6.1 V and 9.2 V, 

 the middle LED will turn red. 


 Top Lamp (Voltage range: 9.3 V ~ 15 V) 

 When the measured value is between 9.3 V and 13.0 V, 

 the top LED will turn green. 

 When the measured value is between 13.1 V and 14.9 V, 

 the top LED will turn orange. 

 When the measured value is higher than 15 V, 

  the top LED will turn red.





  The voltage can also be read on the numeric display screen. 

  The numeric display ranges from ­-45 V to +50.0 V. 

  If the measured value is lower than -45 V or higher than 

  +50 V, the numeric display will show "OL". 

 If the voltage is between ­- 9.9 V and +50 V, the display will be given to within one decimal point. If the voltage is under +­9.9 V, it will be rounded to the nearest whole number.


  2) Frequency Mode: The Frequency is the number of pulses         per second  (Unit: Hz). 
     The numbers indicated in the display are the measured
 up to   999 Hz. 

) Duty Mode: The positive period of one pulse cycle is                 called the Duty  (Unit: %). 

    The numbers indicated on the display are measured duty, 

    ranging between 1% ~ 99%. 


5. Other features 

    1) Auto Power OFF Feature 

       After 3 minutes of non-use, the Gautoprobe automatically shuts itself down to conserve battery life. 

       Press the power  button again to restart the Gautoprobe. 


     2) Changing the probe 

      Use the small wrench provided to loosen the screw and change the probe needle.  

      To use the extension cord, screw it in a clock-wise direction onto the probe. 


6. Maintenance 

 1) Battery replacement: The battery must be replaced when low battery warning sign, "Lob" appears on the display. 

  1. Before changing the battery, make sure that the power is turned off on the Gautoprobe. 

       Also, ensure that the probe and ground clip are not connected. 

       2. Remove battery compartment cover. 

  3. Replace the two LR03 ("AAA" size) alkaline batteries according to their correct polarity. 

       4. Close the cover. 


     2) Cleaning: Periodically wipe the case with a dry cloth. Do not use solvents or abrasives to clean the Gautoprobe.




 Maintenance Examples



1. Speedometer does not work during normal driving

1) Raise the vehicle on a lift, allowing the wheels to move freely.

2) Start engine.

3) Put the car gear into D and let the tires rotate freely.

4) Connect ground cable to the Gautoprobe.

5) Connect ground clamps to the car body.

6) Turn on the Gautoprobe and connect speedometer wiring with the probe.



* When speed sensor of the vehicle has some trouble.

1) In its normal state, speed sensor power and grounding will be the same.

2) Check sensor output which is different from the normal state(blinking on and off), one light remains on(no bliking).


* When the speedometer has some trouble

1) Remove the dashboard and plug the Gautoprobe’s probe in the speedometer wiring on the back of the dashboard

2) If the sensor output is the same as in the normal state, the 1st Blue and 2nd Yellow lamps blink alternately. This

  indicates the signal on the dashboard is normal. If this occurs, it confirms that there’s a problem with the speedometer itself.



2. Car that suddenly stops running and there’s no spark from the spark plug.
    -  The power TR will indicate trouble if it overheats, but will perform normally when it cools down. In this situation,  
        technicians will get in trouble identifying the source of the problem. To overcome this, start engine and wait for a 
        while. After engine get to sufficiently warm, turn off engine and check the power TR immediately.

   1) Turn on the Gautoprobe and connect the ground clamps to car body.

   2) Turn the car key to engage the starter and check each wire on the power TR.



* When the power TR has trouble

Grounding and base are the same in the normal state, but the 3rd lamp turns green.



* When the ignition coil has trouble.

 If the ground, base and collector signals indicate normal conditions, but there’s still no secondary voltage(spark) from the ignition coil, 

  then we can determine that the trouble comes from the ignition coil.

3. The engine does not start

1) Remove the ECU fuse in order to fuel doesn’t get injected into the system.

2) Connect the ground clamps to the battery’s negative(-) pole.

3) Connect the probe of Gautoprobe to the battery’s positive(+) pole.

4) Try to start the engine for about 5 seconds.

5) A technician should watch the lamps of Gautoprobe to see any changes in Voltage.



 * When battery has a problem.

 As time goes by, the voltage will go down to under 9.2V and mid lamp of Gautoprobe will turn red.



 * Repair Tip

    No matter how long you try to charge it, a faulty battery will not charge normally. Replacing the battery 

    is recommended.



4. The window motor does not work properly.


   1) Remove the door trim.

  2) Turn the ignition key to the ON position.

  3) Connect the ground clamps t the car body.

  4) Touch the window motor wiring with the probe and push the window switch.

    5) Check the trouble area while watching the lamps of Gautoprobe to see any changes in voltage.


   * When there’s a problem with the motor.

     The change on the lamps of Gautoprobe is the same as in the normal state, but the motor is not activated.


   * When there’s a problem with the switch.

     When you operate the switch, the lamps of Gautoprobe remains fixed at a constant color(no blinking), different from 

     the normal state.


5. The engine doesn’t start and injector operation is in doubt.

Turn the ignition key to engage the engine.

6.  Neither the injector drive signal or ignition signal are displayed.

  Turn the ignition key to engage the engine.