2 cases of Dongfeng Nissan sedan failure

Case 1

Failure phenomenon: A 2005 Dongfeng Nissan Yida sedan, equipped with a HR16DE engine, with a mileage of 170,000 km. The user reported that the vehicle sometimes suddenly stalled while driving, and when it was restarted, the engine fault light flashed and could not be started. Recently, the frequency of this failure has increased, seriously affecting the use of the vehicle.

Inspection and analysis: After the maintenance personnel received the car, they used Nissan’s special fault diagnosis instrument CONSULT-III to detect the engine, and there was no fault code. After removing and cleaning the injector, throttle and intake manifold, checking the gasoline pump and spark plugs, the car was tested. After driving about 10 km, the fault occurred, but there was still no fault code at this time. A high-voltage spark test was performed with a new spark plug. There was no electric spark, indicating that the ignition coil did not output high voltage electricity. Unplug the ignition coil plug, turn on the ignition switch, and measure the voltage at the power supply end of the plug. It was 6.7 V when static and 4.5 V when starting. According to the circuit diagram of the vehicle (Figure 1), the power supply of the ignition coil is provided by the 47th terminal of the intelligent power control unit IPDM E/R, and the 47th terminal corresponds to the ECM relay inside the IPDM E/R.

Figure 1

The voltage of the 2nd terminal of the IPDM E/R is 12 V, and the 51st terminal is the ground terminal. The 51st terminal is the control terminal of the relay, which is controlled by the ECM. The measurement results show that the working conditions of the ECM relay are normal. Only when the relay fails will the voltage output of the 47th terminal of the IPDM E/R be abnormal. Because the relay is inside the IPDM E/R control unit, it can be determined that the IPDM E/R control unit has failed.

Troubleshooting: After replacing the IPDM E/R control unit, the engine started smoothly. No abnormality was found in the road test. The customer was revisited a few days later, and the fault did not occur again.

Case 2

Fault phenomenon: A 2008 Dongfeng Nissan Teana 250XV sedan with a mileage of 45,000 km. The user reported that the instrument lights of the vehicle suddenly went out while driving, and the speedometer, engine tachometer, and fuel gauge failed, accompanied by the phenomenon of weak acceleration and heavy steering. The vehicle returned to normal after being left for 1 hour, but the fault reappeared after driving for half an hour.

Figure 2

Inspection and analysis: The maintenance personnel used the special fault diagnosis instrument CONSULT-III to detect, and the fault code was: U1001-CAN communication line failure. Because the instrument and all indicator lights did not work, we started with the instrument. The instrument fuse was No. 4 fuse, which was normal after inspection. Turn on the ignition switch and measure the fuse voltage to be 0 V. According to the circuit diagram (Figure 2), the front end of No. 4 fuse is the ignition relay, which is controlled by the body control unit BCM. The control end of the ignition relay, that is, the 6C terminal of the fuse box, was measured to be 0 V. Because the voltage at this point is 0 V, the relay does not work. The 6C terminal of the fuse box is connected to the 82 terminal of the BCM. The line between the two terminals is normal. Therefore, the BCM does not output the control signal of the ignition relay, and it is determined that the BCM is faulty.

Troubleshooting: Replace the BCM, use CONSULT-III to execute “write configuration”, and initialize the BCM (NATS). Test drive, the instrument returns to normal, the vehicle acceleration and steering assist return to normal at the same time, and the fault is eliminated. After a few days of revisiting the user, the fault did not recur.