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Road Speed Sensor Waveform Notes
The Electronic Control Module (ECM) has the ability to adjust the engines idle speed when the vehicle is slowing or stationary by using information from the Road Speed Sensor (RSS). The sensor is a 3 wire device and will have a supply at battery voltage, an earth and a digital square wave output also switching at 12 volts.
With the appropriate electrical connection made to the RSS output, raise one wheel with a trolley and place an axle stand under the suspension unit. Start the engine and select a gear, a waveform switching from 12 volts to zero should be seen. As the road speed is increased the frequency of the switching should be seen to increase. This change can also be measured on a multimeter with frequency capabilities. The sensor will be located on either the speedometer drive output from the gearbox or to the rear of the speedometer head.
汽車診斷 | 汽車診斷儀 | 汽車故障診斷儀 | 汽車測試儀 | 汽車分析儀 | 汽車診斷示波器 | 汽車電路測試儀 | 汽車電路分析儀 | 發動機分析儀 | 發動機綜合分析儀 | 發動機檢測中心 | 點火分析儀 | 點火測試儀 | 汽車傳感器測試儀 | CAN總線示波器 | LIN總線示波器 | 汽車故障記錄儀 | 汽車傳感器分析儀 | 汽車檢測儀 | 噴油嘴測試儀 | 點火線圈測試儀 | 蓄電池測試儀 | 發電機測試儀 | 起動機測試儀 | ABS傳感器測試儀 | ECU測試儀 | ECM測試儀 | 進氣真空/壓力測試儀 | 排氣壓力測試儀 | 汽車技術培訓 | 爆震傳感器測試儀 | 缺火測試儀 | 缺缸測試儀 | 線路測試儀 | 引出線 | 汽車數字示波器 | 真空傳感器 | 高壓感應測試頭 | 無分電器點火測試頭 | 獨立點火（COP）感應測試頭 | 漏電測試儀 | 氣缸相對壓縮測試 | 電腦測試儀 | 發動機控制器測試儀 | 泄漏測試儀 | 熒光檢漏 | 超聲波檢漏 | 汽車數字萬用表 | 電流鉗表 | 電流勾表 | 點火正時燈 |
