Engine model:Cummins ISLe
Fault Phenomenon:
Owner reflects that fault light suddenly lit under normal driving and fail to accelerate.
Fault diagnosis and analysis:
According to vehicle model and vehicle information, this vehicle is Euro III electronically controlled system, need to use Fcar automotive scan tools to diagnose,
diagnosis method by Fcar automotive diagnostic tool as below:
1. To find 9-pin diagnostic socket position, located near right side relay of shift lever(See picture 2);
2. Connect testing cable to 9-pin diagnosis head and car diagnostic equipmentl's main unit;
3. Connect diagnostic socket, turn ignition switch to ON after confirm connection normal;
4. Power on Fcar truck diagnostic tool Power switch;
5. Enter Menu and select【Diesel】——【Cummins】——【V6.0】——【Cummins diesel engine】——【Cummins ISLe engine _ 24V】——【Read DTC】——DTC display【0428 fuel moisture indicator sensor circuit –voltage above normal or short to high voltage supply】——【Clear DTC】——【DTC clear success】——【Read Data stream】——【0428 fuel moisture indicator sensor circuit –voltage above normal or short to high voltage supply】fault code appears again,means this faul code is real.
6. Base on analysis of【0428 fuel moisture indicator sensor circuit –voltage above normal or short to high voltage supply】,it was caused by excessive water filtered by oil-water separator and sensor line fault or short circuit.
7. Function of oil-water separator:
When compressed air that containing a large amount of oil and water solid impurities enters the separator, spin down along the inner wall, produced centrifugal effect so that oil-water precipitated from the vapor stream along the wall flows down to the bottom of the oil-water separator, and then conduct fine filtration by filter. Because the filter are stacked by coarse, fine, ultrafine three fiber filter material, having a high filtration efficiency and resistance is small, when the gas passes through the filter, is firmly adhered to the filter fiber and increases gradually into droplets, and drop wise to the bottom of the separator under gravity, due to the barrier of the filter element, inertial impaction, and the intermolecular van der Waals force , the electrostatic attractive force, and vacuum suction. Normally no problem will occurs to discharge from the drain valve. Except for water separated from oil-water separator in winter time freeze, will cause energy supply gas circuit clogged, affecting the braking force to pass, resulting in actuation force reduction of brake when brake and braking force insufficient when oil-water separator leak.

Fault diagnosis Fcar universal diagnostic tool
1. To measure whether working voltage of sensor is 5V,return line is normal with multimeter。
2. Whether drain bolt is dismantled and water excessive。
3. TO measure resistance of sensor is within normal value 3500 ohm。

Troubleshooting by Fcar automotive diagnostic tool:
When inspect oil-water sensor, no sensor was found and oil-water separator without sensor; for the convenience of repair, you can find 3500 ohm or so of resistance to connect in series as substitute, and then use Fcar auto scan tool【Clear DTC】——【DTC Clear success】——Fault light off, road test system normal, trouble removed.
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