奧迪A8突然無法啟動，檢查好汽車搭鐵點
Audi A8 suddenly failed to start, check the car tie point.
毛病現象
Fault phenomenon
一輛2013款德國原裝奧迪A8(D4)轎車，搭載 CGW型發動機，行進路程2231km，客戶反映昨晚低速行進中發動機俄然熄火，再也無法啟動。
A 2013 German Audi A8 (D4) sedan with a CGW engine travels 2,231 km. Customers report that the engine suddenly stalled during the low-speed drive last night and could no longer start.
毛病診斷與掃除
Diagnosis and elimination of defects
將車拖進廠，測量蓄電池無電，用充電機對其充電，等充電完結，車輛能重新啟動。銜接診斷儀檢測毛病碼，發現在所有操控單元均存儲“電源電壓過低，偶發”；在發動機、變速器、車門操控單元存儲“無信號/通訊”。初步判斷這些毛病碼皆因蓄電池電量過低而被存儲。
Pull the car into the factory, measure the battery is dead, charge it with a charger, and when the charge is over, the car can restart. Connection diagnostic instrument detects defect codes and finds that "low power supply voltage, occasional" is stored in all control units, and "no signal / communication" is stored in engine, transmission and door control units. It is preliminarily judged that all these codes are stored due to the low battery power.
使用診斷儀的毛病引導功用，經過查看發電機工作狀況記載檢測到“溝通發電機毛病，1次”，發生在 18:34。
Using the fault guiding function of the diagnostic instrument, after checking the working status of the generator, the fault of the communication generator was detected once, which occurred at 18:34.
問詢客戶在熄火前有無“充電正告燈報警、電量低需封閉音響的提示”，客戶反映報警、提示都沒有。
Ask customers whether there is a "charge warning lamp alarm, low power demand closed sound warning" before extinguishing, customers reflect the alarm, prompts are not.
再次查詢毛病碼（表1），“無信號/通訊”均發生在18點34分左右，“電源下限達不到”均發生在21點 9分左右，闡明先因“無信號/通訊”毛病導致發動機熄火，終才呈現電量低的狀況。
Query the defect code again (Table 1), "no signal / communication" occurred at 18:34 or so, and "the lower limit of power supply can not reach" occurred at 21:9 or so. It is clarified that the engine stalled because of the "no signal / communication" fault, and finally showed a low power situation.
“無信號/通訊”毛病一般是操控單元正極供電線或接地線斷路形成，本車多個操控單元在同一時間存儲這個毛病碼，應是由一個毛病點引發。閱覽電路圖，看到發動機、變速器、右前門J387、右后門J389等操控單元，正極供電是不同線路，而接地線共用右A柱下方的43號搭鐵點搭鐵。
The trouble of "no signal/communication" is usually caused by the break of positive power supply wire or ground wire in the control unit. The trouble code stored by several control units in the same time should be caused by a fault point. Reading the circuit diagram, we can see the engine, transmission, right front door J387, right rear door J389 and other control units, the positive power supply is different lines, and the grounding line shares the right A column below the 43 pick-up point.
拆檢右 A 柱下方43號搭鐵點，發現搭鐵點接觸不良，斷開此搭鐵點后電動電扇常轉無法封閉。
Remove and check the No. 43 tie-in point under the right A pillar and find that the tie-in point is not in good contact. After disconnecting the tie-in point, the electric fan can not be closed.
緊固43號接地址螺栓，毛病掃除。
Tighten the No. 43 address bolt and remove the trouble.
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