1. Failure phenomenon
Since the starter motor does not run, the engine cannot be started.
2. Starting system circuit diagram
Starting system circuit diagram is shown in Figure 1-1.
3. Troubleshooting and troubleshooting steps
(1) First check whether the fuse in the circuit is blown. Once the fuse is blown, the start switch will be powered off, the starter motor will not run, and the engine will not start: After replacing the blown fuse, start the motor and the engine will start. If, after replacing the fuse, the starter motor still does not run, the next step is to check.
(2) Check whether the battery voltage is above 24V, and the density of the electrolyte is 1.26 × 10kg / m2. If the density does not meet the regulations, it means that the battery capacity is too low or there are other failures, the battery should be charged or replaced.
(3) If the battery voltage and electrolyte density are normal, turn the start switch from the on position to the off position, and observe whether the battery relay sounds.
(4) If there is no sound from the battery relay, further check whether the voltage of the start switch terminal B is in the range of 20 ~ 29V (the positive electrode of the multimeter is connected to the start switch terminal B, and the negative electrode is connected to the negative terminal of the battery). If the voltage is abnormal, check whether the wiring harness between the positive terminal of the battery, M11-M7 (1), fuse, M1 (1), and start switch terminal B is poorly connected or broken. After repairing or replacing the wiring harness, start the motor. The engine can be started when it is running.
(5) If the voltage of the start switch terminal B is in the range of 20 ~ 29V, then further check whether the start switch terminal B and the terminal BR are connected (turn on the start switch, remove the terminal B), if not, then It means that there is a fault between the start switch terminal B and terminal BR. After replacing the start switch, the starter motor can run.
(6) If the start switch terminal B and terminal BR are conductive, then further check whether the resistance of the wiring harness between the start switch terminal BR and the battery relay terminal is normal (the resistance between the start switch terminal BR and the battery relay terminal The maximum value is 1Ω, the minimum value of the resistance between the wiring harness and the chassis is 1MΩ, disassemble the start switch and both ends of the battery relay), if the resistance is not normal, then further check the start switch terminal BR-M1 (2) -M20-D10- M7 (2) Whether the wiring harness between the battery relay terminals is bad or broken, after repair or replacement, the starter motor can be run and the engine can be started.
(7) If the resistance value of the wiring harness between the start switch terminal BR and the battery relay terminal is within the standard range, then further check whether there is continuity between the negative terminal of the battery terminal and the battery relay terminal -b, if not, then check the battery terminal Whether the wiring harness between the negative electrode and the battery relay terminal -b is in poor contact. After repair or replacement, the motor can be started and the engine can be started.
(8) If the negative terminal of the battery terminal is connected to the battery relay terminal -b, it means that the battery relay is faulty. After the battery relay is replaced, the motor can be started and the engine can be started.
(9) If the battery voltage and electrolyte density are normal, when the start switch is turned from the on position to the off position, the battery relay has a sound, then turn on the start switch, and observe whether the gear of the starter motor has moved outward Sound? If not, continue to check whether the voltage between the start switch terminal C and the chassis is normal (turn on the start switch, the voltage is about 24V), if the voltage does not reach 24V, it means that there is between the start switch terminal B and terminal C Failure, after replacing related parts, the starter motor can run and the engine can be started.
(10) If the voltage between the start switch terminal C and the chassis reaches 24V, check the start switch terminals C-Ml (4)-M14 (1)-E8 (1)-M2 (1) between the start motor terminal S Whether the wiring harness is bad or broken, after repair or replacement, the fault can be eliminated.
(11) If the starting motor gear has a noise of outward movement, continue to check whether the voltage between the starting motor terminal B and the chassis is normal (turn on the start switch, the voltage is 24V), if the voltage does not reach 24V, then further check the battery terminals Whether the wiring harness between the positive pole and the starting motor terminal B is bad, the fault can be eliminated after repair.
(12) If the voltage between the starter motor terminal B and the chassis is normal, it means that the starter motor is faulty. After replacing the starter motor, the fault can be eliminated and the engine can be started.
