Model: F02, configuring N54 engine. Driving mileage: 400km. Fault phenomenon: when the user reflects the bumpy road or sometimes the steering wheel drives to the side, the gear will automatically jump to the neutral gear. And the engine fault lights are temporarily lit up before the gear is stopped, and then the vehicle can move forward. Fault diagnosis: after connecting ISff) to carry out diagnostic test, read fault contents as follows: • D02D58 one signal (motor 1 wheel torque, 41.3.4) invalid, DME / DDE transmitter D01557 information (motor 1 wheel torque, 41.3.4) missing, receiver ICM, transmitter DME / DDE / D01558 information (motor 2 wheel torque, 41.3 .4) missing, receiver ICM, transmitter DME / DDE / D01556D information (motor 3 wheel torque, 41.3.4) missing, receiver ICM, transmitter DME / DDE D01570 one information (motor 4 wheel torque, 41.3.4) missing, receiver ICM, transmitter receiver / decoder information (motor 5 wheel torque), receiver, receiver, Emitter DME / DDE / D01A08 one information (motor 6 wheel torque, 41.3.4) missing, receiver ICM, transmitter DME / DDE D01646 information (acceleration pedal rod angle, 40.1.4) missing, receiver ICM, transmitter DME / DDE • one information (motor 1 wheel torque) missing, receiver F02 one signal (wheel standard torque, 40.3.4) is invalid, information DME / DDE transmitter. Delete the fault storage for the road test, in the course of the test in the process of a section of the deceleration zone, the engine fault lights suddenly light, then the engine speed suddenly rise very high, the block jump to the air. Re connect ISff) for diagnostic testing, and read the fault contents consistent with the above. Execute the test plan and divide the above fault into two broad categories. 1. (3AN / FlexP, aV bus system analysis: information loss; C; AN / FlexR. AV bus system analysis: interface failure information "signal is invalid". When the receiving control module does not receive the information sent by the transmission control module, the receiving control module records the "information loss" failure. This kind of fault occurs mainly when the physical connection between the participating control modules is disturbed. The possible reason: the bus wire grounding short road bus wire short circuit to the power supply voltage. Short circuit breakage (wire breakage) between bus wires. Damage, corrosion, and dirty touch point joint. Control module malfunction (such as plug connection damage, very few cases). The most likely failure cause of the incorrect (bus connection) calculation letter self embedded Fuf. The detection step will limit the fault by automatic analysis of the fault record. The o detection plan, determined within the defined range (probability calculation), is shown as follows: the information DME----***----- (8/16) missing from the transmitter (8/16) starts to find the fault from the area of the most likely control module. If necessary, continue to locate faults in the second possible high control module area. The possibility of failure is corresponding to the number of asterisk displayed (*). * * * * *: high possibility; *: low possibility. In addition, the stored faults and the maximum number of faults can be displayed in parentheses. For example, "5 / 46" indicates that the total l of the corresponding control module has 46 possible faults, including 5 faults. In most cases, many of the information malfunction control modules do not list all the possible failures because the information failure is connected to the corresponding vehicle functions. For different control modules, different vehicle types and different special equipment, the maximum possible number of failures varies. When there is little information failure in the corresponding control module, the value expressed in parentheses is especially meaningful, for example, "2 / 2". If the fault share of the other control module is summarized as "23 / 65", it should focus on the previous control module area when finding the fault. L special situation: it can be imagined that in special cases, a reception control module may record information failures of different radio stations, although the receiving control module itself will not appear in the (fault) profile, because other control modules do not need the information of the receiving control module at all. For example, if the control module with multiple failures in the summary is low, additional fault data should be checked. If the location is always referred to as the same receiver, continue to troubleshooting in the control module. Tip: systematic analysis of missing information involves occasional failures. If there is a continuous system failure, the fault should be identified when the vehicle is tested. The fault storage is associated with the DME, and the detection plan analysis also believes that the possibility of DME's failure is higher than other control modules. Then the power supply, grounding and terminal connection of DME are checked, and the results are normal, so the analysis thinks that there is a fault inside the DME. When the vehicle runs in a bumpy road or in the direction of the direction, the DME can not transmit the torque output information to the bus normally on the bus. The transmission control module immediately jumps to the gap without information. Replacement of DME control module, programming and code for vehicles, repeated road test, failure phenomenon did not appear again, troubleshooting.