2）”Multimeter” mentioned below is digital multimeter, and it’s forbidden to check electrical control system by indicator-type multimeter;

3）If fault code indicates that some circuit voltage is too low, it indicates there is short circuit or open circuit to grounding in the circuit; if fault code indicates that some circuit fault, it indicates there is open circuit or several circuits fault in the circuit.

2、Diagnosis Help

1）If fault code can’t be erased, the fault is steady state fault; if it’s occasional fault, firstly check whether there is loosen phenomenon in wiring harness connector;

2）When maintaining, don’t ignore influence of vehicle maintenance condition, cylinder pressure, battery power to system.

3、Losing Efficacy Strategy

According to fault state of electrical control system, running strategy is divided into 4 classes:

① First class: default value ② Second class: reduce torque (limit torque) ③ Third class: go home laming (electronic accelerator lose efficacy, engine speed gets limited) ④ Fourth class: stop engine.

Fault code—Battery

Fault code—Brake switch

Fault code—Water in fuel level sensor

Fault code—Starter relay

Fault code—Compressor relay

Note: The fault code only is compressor relay fault, not involved compressor.

Fault code—Exhausting brake relay

Note: The fault code only is exhausting brake relay fault, not involved exhausting brake valve.