Please Excuse Our Mess! We're Creating A New and Improved Community Experience.
Take the commonly used K line communication of connection method steps make a detailed description
November 12, 2014 www.fcar.com

Take the commonly used K line communication of connection method steps make a detailed description

Posted in Forum Post

Connection method of K line communication diagnostic socket
1、Connection method of CAN line communication diagnostic socket
K line signal voltage is 1V or so lower than battery voltage, Eg, if battery 12V, then signal voltage is about 11V, battery 24V; if battery 24V, then signal voltage is about 23V. When actually measure voltage of pin on vehicle diagnostic socket, there might be deviation of ±0.25V.

Connection method for K line communication with diagnostic socket and Fcar jumper box as shown in picture: signal wire connect to No.7 hole, power line(battery voltage) connect to VCC hole, ground wire connect to GND.

CAN line communication adopts double line of communication, under the condition that ignition switch on, to measure voltage of 2 diagnostic wire with multimeter.
The sum of voltage for the two is 5v, CAN-H line voltage is 2.5+0.25V, CAN-L line voltage is 2.5-0.25V,actually there might be deviation of ±0.25V or so.

Connection method for K line communication with diagnostic socket and Fcar jumper box as shown in picture
CAN-H connect to No.6 hole, CAN-L connect to No.14 hole, power line(battery voltage)connect to VCC hole, ground wire connect to GND.

Note: When actually measure voltage of pin on vehicle diagnostic socket, there might be deviation of ±0.25V.
Connect jumper box with main testing cable, and lock  fastening bolts, as shown in left picture.
15 jumper connection holes with numbers marked beside will be seen on jumper box, the corresponding numbers to these connection holes is node relation of standard OBD-II port.

Base on diagnostic socket information of vehicle, connect diagnostic interface of jumper box.
After connection, turn on ignition switch to ON, at this time power indicator light on jumper box shall be on. Press switch of F3-D main unit,F3-D main unit work properly, appropriate system can be selected for diagnosis.

Note: If lack of knowledge about vehicle electrical equipment or cannot confirm power supply to electrical equipment, please don’t perform jumper operation, for error jumper operation will lead to vehicle electrical equipment or Fcar main unit and cable malfunction.

Vehicle diagnostic equipment socket related information confirm and tools:
(1)、Digital high impedance multimeter(must use high impedance multimeter, otherwise will cause damage to computer board)
(2)、When ignition switch to ON, diagnostic socket has supply voltage from vehicle, the voltage difference between voltage on diagnostic socket and that of vehicle battery end cannot be above 2.5V.
(3)、If signal line used in diagnosis is signal wire communication (K line),voltage on signal line is 1V lower than battery voltage(if vehicle supply voltage is 12V,then voltage of signal wire is 11V±0.25V; if 24V supply, voltage of signal line is23V±0.25V).
(4)、If the communication of duel signal line adopts CAN communication, under the condition that two diagnostic lines in ignition switch on, to measure voltage of ground wire. The sum voltage is 5V, CAN-H line voltage is 2.5V+0.25V,CAN-L line voltage is 2.5V-0.25V, actually there may have deviation of ±0.25V or so.

After connection, turn on ignition switch to ON, at this time power indicator light on jumper box shall be on. Press switch of F3-D main unit,F3-D main unit work properly, appropriate system can be selected for diagnosis.

Note: If lack of knowledge about vehicle electrical equipment or cannot confirm power supply to electrical equipment,please don’t perform jumper operation, for error jumper operation will lead to vehicle electrical equipment or Fcar main unit and cable malfunction.
Vehicle diagnostic socket related information confirm and tools:
(1)、Digital high impedance multimeter(must use high impedance multimeter, otherwise will cause damage to computer board)
(2)、When ignition switch to ON, diagnostic socket has supply voltage from vehicle, the voltage difference between voltage on diagnostic socket and that of vehicle battery end cannot be above 2.5V.
(3)、If signal line used in diagnosis is signal wire communication (K line),voltage on signal line is 1V lower than battery voltage(if vehicle supply voltage is 12V,then voltage of signal wire is 11V±0.25V; if 24V supply, voltage of signal line is23V±0.25V).
(4)、If the communication of duel signal line adopts CAN communication, under the condition that two diagnostic lines in ignition switch on, to measure voltage of ground wire. The sum voltage is 5V, CAN-H line voltage is 2.5V+0.25V,CAN-L line voltage is 2.5V-0.25V, actually there may have deviation of ±0.25V or so.

Comments (0)

Leave a reply