Case 1
Failure phenomenon: a 2009 Dongfeng Nissan new Teana sedan, equipped with VQ25DE engine and REOF10A type continuously variable transmission, mileage 982 km. The car lost power steering because the function was towed to a service station maintenance.
Check Analysis: First, verification failure phenomenon, the steering wheel feels very heavy rotated, a slight improvement when refueling. Car uses electronically controlled hydraulic steering system EPS, and found to be substantially vehicle steering oil leakage check, but still within the range of the standard power within the oil storage tanks. Nissan dedicated connection fault diagnostic apparatus CONSULT-3 into the fault diagnosis, the system of no fault code storage, the data stream is also not unusual. The principle of the easier, the first solenoid valve measured steering resistance 4.8 Omega ;, compliant 4 ~ 6 Omega; standard initial troubleshoot solenoid valve. Since the steering solenoid valve assembly is steering member, a steering unit must be removed to inspect or replace the solenoid valve. So after the failure of the vehicle lifted to working height, allowing maintenance personnel to start the engine in the car, I observed the power steering pump in the car, was found with increasing engine speed, the front of the power steering pump oil droplets fall significantly. At this point already determined to be caused by the power steering pump pressure relief function failure.
FIG 1
Solution: Replace the power steering pump (1), test function returned to normal steering.
Case 2
Failure phenomenon: a 2009 Dongfeng Nissan new Teana sedan, equipped with VQ25DE engine and REOF10A type continuously variable transmission, 9 500 km mileage. It says users, ABS fault car dashboard warning light is on.
FIG. 2
Check Analysis: First, using a dedicated Nissan CONSULT-3 fault diagnostic trouble code reading system, the ABS control unit stores the current DTC C1107 (FIG. 2), meaning ldquo; right front wheel speed sensor -2rdquo ;. After that communicate with users, ABS warning light is travelingAfter an emergency braking lights. The description of the user, maintenance personnel suspected wheel speed sensor malfunction or damage caused by dirt, then a signal on the disk wheel speed sensor and the hub bearing cleaning, but cleaning failure remains.
The author of the DTC storage is analyzed, as the meaning of the right front wheel speed sensor 2 in the right front wheel speed sensor is short circuit, or the distance between the disk rotation speed sensor and the signal is too large, and the ABS control unrecognized pulse sensor unit. Fault Possible causes include faulty wheel speed sensor and the signal line disk, since maintenance personnel have the relevant circuits and sensors were examined, the bearing surface also found no problems. At this time maintenance staff, said in the wheel bearings found in some wrapped in wool signal in the disk, so using a task light inspection, found that there are gaps and disk signal event of wear. Remove the right front wheel bearings, magnetic bearings have found a more serious wear and tear (Figure 3), the magnetic powder have all come off.
Figure 3
troubleshooting: After replacing the right front wheel axle bearing assembly, commissioning fault completely ruled out.
reviewed: When we repair some of the fault codes stored in a vehicle, be sure to clear the fault code meaning, or take a roundabout in the repair work or hard to find fault location.
(Yang Weijun)