A Santana GLi sedan with a mileage of 100,000 km. The car lights are bright, but there is no alarm with the buzzer. When the maintenance personnel took over the fault case, the vehicle had been overhauled due to the above phenomenon, and the second disassembly of the engine, the adjustment of the crankshaft bearing (large tile) and connecting rod bearing (small tile) gap work has been completed , But the fault still exists.
    Under normal circumstances, open the ignition switch, the instrument panel on the oil pressure alarm light will be lit, until the vehicle starts off. If the oil pressure is less than 30kPa at idle or less than 180kPa at 2000r / min, the oil pressure warning light will be illuminated again and accompanied by the alarm of the buzzer. While in other cases the oil lamp lights up, mostly due to circuit failure. But because the car has been carried out before the maintenance, maintenance personnel prudent, first check the engine lubrication system. First through the dipstick to check the engine oil, oil sufficient. Then check the engine cylinder head behind the oil on the low-voltage switch and oil filter cover installed on the high-voltage switch cable, no short circuit or open circuit phenomenon, and then down the steps need to use the intuitive pressure gauge and multimeter. (Low-voltage switch is normally closed switch), with a multimeter to measure the resistance of 0Ω, indicating that the switch is normal.
    And then the pressure gauge and the switch together with the oil on the road, which can simultaneously detect oil pressure and switch failure, the vehicle idling oil pressure of not less than 30kPa, indicating that the engine lubrication system without fault, when the oil pressure is higher than 30kPa Multimeter measurement low-voltage switch resistance ∞, once again proved low-voltage switch intact. Using the same method to measure the oil filter cover on the high-pressure switch and oil pressure (high-voltage switch is normally open switch), multimeter shows its resistance is ∞, the engine speed rose to 2000r / min when the oil pressure of not less than 180kPa , Which further illustrates the lubrication system without fault, when the oil pressure is higher than 180kPa with a multimeter to measure the high voltage switch resistance is 0Ω, indicating that the high voltage switch is not damaged.
    Through the above check did not find the oil pressure alarm light reasons, maintenance personnel will focus on the hydraulic controller and its related circuit. Remove the dashboard from the back of the 14-hole black and 14-hole white sockets, check the odometer on the odometer frame to check the controller's 6 terminals (the controller 1 column is connected to the ignition coil negative transmission speed signal, 2 columns are 3 column is to the oil warning light, 4 column is through the ignition switch power cord, 5 column is to the oil pressure high pressure switch, 6 column is to the oil pressure low pressure switch), to see whether there is short circuit or The phenomenon of breaking.
    The above check still did not find the reason to make the oil lamp lit, just as the maintenance personnel were ready to continue checking and replacing the oil pressure controller, the driver of the car told the maintenance personnel that the vehicle would not start before the overhaul And the phenomenon of flameout. In the absence of changeover oil pressure controller, the maintenance personnel quickly collated and reviewed the above steps. There is a wire transmission speed signal at the wiring of the No. 1 terminal of the controller to the negative pole of the ignition coil. Start and stop the only place, because if the speed signal is not allowed to lead to flameout and easy to start the fault. And the speed is not allowed to lead to the failure of these common components only ignition coil, so the ignition control module is judged to be damaged, replace the ignition control module after the fault really excluded.