Case 1
Failure phenomenon: a 2005 annual Nissan Tiida sedan, equipped with HR16DE engine, mileage 170 000 km. Reflect the user sometimes suddenly turn off the vehicle is traveling, upon restart, the engine fault light flashes, can not be started. Recent frequency of this failure is increasing, seriously affecting vehicles.
Check Analysis: pick the maintenance staff, with Nissan CONSULT-III-specific fault diagnostic apparatus for detecting an engine, no fault code. Washable injector, a throttle valve and the intake manifold, fuel pump inspection, after the spark plug test, after running about 10 km, failure occurs, but this time still no fault code. For high-voltage flashover test new spark plugs, no spark, no output high voltage ignition coil described. Disconnect plug ignition coil, the ignition switch is opened, the plug power supply terminal voltage measurement, static when 6.7 V, the starting of 4.5 V. Now a circuit diagram of the vehicle (FIG. 1), provided that the power supply of the ignition coil 47 by the power control unit intelligent terminal IPDM E / R, and the corresponding terminal 47 is inside the IPDM E / R relays the ECM.
FIG 1
2-terminal voltage
Measurement IPDM E / R of 12 V, with a terminal 51 to ground. No. 51 terminal is the control terminal of the relay, is controlled by the ECM. ECM relay measurements show normal working conditions, only fault relay, the terminal 47 will make the output voltage IPDM E / R abnormality. Due to internal relay IPDM E / R control unit, it can be determined IPDM E / R control unit failures.
troubleshooting: After replacing IPDM E / R control unit, the engine start smooth. Road test showed no abnormalities, a few days after the visit customers, this failure does not occur again.
Case 2
Failure phenomenon: a 2008 annual 250XV Nissan Teana sedan, mileage 45000 km. The user is reflected in the car dashboard lights went out traveling, speedometer, an engine tachometer, fuel gauge failure, and associated accelerationWeakness, steering becomes heavy phenomenon. After 1 h at normal vehicle, but after half an hour with the failure to reproduce.
FIG. 2
Check Analysis: maintenance personnel with special CONSULT-III diagnostic fault detection, fault code: U1001mdash; mdash; CAN communications line failure. Because all instruments and lights do not work, so start with the meter start. 4 meter fuse is a fuse, the fuse properly after inspection. The ignition switch is opened, the measured voltage is 0 V. For fuse Now the circuit diagram (FIG. 2) that the front end 4 of an ignition fuse relay, cell relay control BCM controls the ignition of the vehicle body. Measuring the ignition relay control terminal, i.e., the fuse box 6C terminal voltage of 0 V. For Because where the voltage 0 V, the relay does not operate it. 6C and terminal 82 is connected to the terminal of the fuse box BCM, conduction between the measuring lines of two terminal through normal, and therefore no control signal is outputted BCM ignition relay determining BCM failure.
Troubleshooting: BCM replacement, performed with CONSULT-III ldquo; rdquo ;, arranged to write BCM initialized (NATS). Test, the instrument returns to normal, vehicle acceleration, power steering while restoring normal troubleshooting. A few days after returning users, the fault does not occur again.
(Fujun)