Case 1
Failure phenomenon: a 2006 model year Nissan Teana 2.5 L sedan, the car used Nissan NATS alarm system with keyless start function. In a newly built car service shop repair, maintenance staff to help the author says the car can not be registered smart key.
examination Analysis: After the service personnel to communicate with each other, I learned that the car can not be registered in addition to the smart key, other functions are normal, smart key system can also be found in the car, but also unregistered key normal, thereby substantially exclude the possibility of a failure and a smart key control unit BCM body control unit, the author determines problems may be related vehicle antenna empirically.
Figure 1
because the other side is not relevant maintenance experience, so the vehicle to the service shop where the author to be checked. I use a dedicated Nissan CONSULT-Ⅲ fault diagnostic tests related systems, found no fault code stored prompt can not be registered when the registration key. Nissan NATS system to receive signals smart key by three internal antennas and three external antenna (FIG. 1), and then fed back to the body control unit the BCM, for controlling the door unlocking and locking, ignition start, and a key registration function switch.
Analysis of the author, and registration of the main antenna includes an antenna inside the instrument panel 2 and the center console of the antenna 1, the main function is to use the smart key receives the registration signal and feedback. Since the two antennas in the center console and the instrument panel, disassembly more trouble, in order to determine their own judgment, the author uses the antenna in the fault diagnostic unit active test smart key, the smart key in the vehicle, the ignition off performing antenna switching active test, no reaction was found only after the antenna 1 is closed, as long as the other antenna is a disconnected emergency lights will flash, so that the fault position can be determined substantially decided to check the antenna 1. Remove the center console behind the fascia, found indoor antenna 1, the wire harness plug socket is not found on the antenna (FIG. 2).
FIG. 2
Troubleshooting: Find harness connector antenna (FIG. 3), is pressed against foundPlastic floor below. The plastic floor apart, find the plug is connected to the antenna, re-register the smart key, the system displays the registration was successful.
Figure 3
reviewed: some failures in the maintenance of electrical systems, familiar with the system components is important, this can quickly find cause of issue.
Case 2
Failure phenomenon: a 2007 annual Nissan Tiida 1.6 L sedan, equipped with HR16DE engine and 5-speed manual transmission, mileage 50000 km. According to reflect the user, the engine fault light on the vehicle instrument lighting.
Figure 4
Check Analysis: Nissan CONSULT-Ⅲ dedicated fault diagnostic trouble code read, store fault code P0335 (crankshaft position sensor circuit) . Service personnel related circuits were checked, but found no problems, so after clearing vehicle fault codes given to the user. User and because the next day engine fault lights up into the plant maintenance. Service personnel use the oscilloscope waveforms crankshaft position sensor is collected (FIG. 4), and found no abnormalities; has a crankshaft position sensor about the failure, the refrigerant pressure sensor, and an engine control section unit or the like were replaced, but the fault does not Variety.
The author then decides the engine wiring harness lines reconfirmation. Check the connections at each of the wire harnesses and plugs, plug stumbled abnormal engine control unit, not the side snap real card (FIG. 5).
Figure 5
Troubleshooting: real card plug not repair, test troubleshooting.
reviewed: Since the plug snap separating the engine control unit, ECM lead pin can not be inserted in place. When the vehicle is running rough improper contact plug, causing engine failure lights.
(Yang Weijun)