ECU determines the operating condition of the engine according to the current engine speed, water temperature, atmospheric pressure and throttle position. So how to solve the ECU failure?
Let’s popularize a knowledge first. When many maintenance workers use the diagnostic instrument to measure the engine control system, the measured synchronization signal data of crankshaft and camshaft is very important. This data is a number after being read out by the decoder. Many maintenance workers do not understand what this number represents. Please see the figure below.
If the synchronization signal is normal and the synchronization signal display data is 48, the engine must meet the following conditions of sensor fault:
1. There is no fault record in the fault memory;
2. Crankshaft sensor works normally;
3. The camshaft sensor is operating correctly.
Recently, a maintenance worker encountered such a fault:
The fault code is displayed as p0607, p100e (ECU restart) of sensor fault
Through computer inspection, it is found that the cam signal and speed signal are not synchronized between 1300 rpm and 1800 rpm. The displayed data is 129 and the normal is 48 of sensor fault.
129 is interpreted as “engine operation through redundant sensor system”
If the engine runs too long in the speed range of 1300-1800 rpm, the ECU will restart in order to protect itself, and the ECU backup data will overwrite the calibration data. Due to the short power failure of ECU, the oil pump metering unit is turned to the maximum
According to this phenomenon, the signal hole spacing of the flywheel was checked first, and the results were normal. Finally, it was decided to replace the engine harness. During the replacement, it was found that the harness was squeezed by M10 bolts at the back of the left headlamp of the vehicle. After the wire speed was squeezed, the resistance was too large, and it could be normal at low speed. Once it reached high speed, the current change was abnormal, causing the two signals to be out of sync, resulting in failure. Replace the engine harness and solve the problem.