This model usually adotps CAN communication protocol (Not excluding some Euro IV vehicle that still adopts Euro III standard, Such as FUSO) Diagnostic socket is normally 4 pins: ground wire, fire wire, CAN_H, CAN_L, voltage measured is: 0V, 24V, 2.5+V, 2.5-V.The pin that little higher than 2.5V is CAN_H,another is CAN_L. Connection method for jumper box is the same as above,connect CAN_H with 6# , connect CAN_L with 14#,then you can diagnose with F3-D Truck Diagnostic Tools connec tify.If still fail to test,pls contact Overseas Dept. for assistance.
Node relation of jumper box is:
1#:K line; 2#:K line;
3#:K line; GND:Ground wire(negative);
7#:RSR232+, J1708+, K line;8#:K line;
9#:K line; 10#:K line;
11#:K line; 12#:K line;
13#:K line; 14#:CAN‐L;
15#:RSR232‐, K line, J1708‐, L line
VCC: power line(Positive); POWER:Power indicator.
Remark: If lack of vehicle electrical equipment knowledge or unable to confirm electrical equipment power supply, please don’t operate jumper, for error operation of jumper may lead to malfunction of electrical failure or FCAR F3-D diesel diagnostic equipment main unit and wire.     
(Auto diagnostic socket related information reconfirmed as below)
● Digital high impedance multimeter (can not use Analog Multimeter)
● When ignition switch to ON, there is supply voltage of vehicle on diagnostic socket. Voltage difference between voltage on diagnostic socket and vehicle battery side can not be above 2.5V.

 In diagnosis with diesel diagnostic equipment, if the signal line used is single-line communication (K line), voltage on signal line lower than battery voltage,(if vehicle supply voltage is 12V,then voltage on signal line is 11V, + 0.25V;if 24V,signal voltage is 21V,+ 0.25V) If double signal line adopts CAN communication, 2 diagnostic lines use multimeter to measure ground wire voltage under the condition that ignition switch On, the sum of both voltages is 5V,average 2.5V,the one voltage little higher than 2.5V is CAN-H, the one voltage lower than 2.5V is CAN-L.
After understanding of the above, then you can use F3-D diesel diagnostic equipment to read DTC.
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