A Benz E200 made 2013 with 140 thousands kilometers, the owner described that: the check engine light on and engine shaking vibrating.Here I share the whole repair process of how to solve Benz E200 Check Engine Light on & Engine Shaking Vibration.
Trouble Diagnosis:
Technicians check the maintenance histor, found maintenance record was normally. Technicians diagnosed the Benz E200 by MB Star DAS, found the trouble code:P030100.It means ” Cylinder 1 Misfire Detected “.
According to past auto repair experience, usually carbon buildup generated by dirty oil-way will result in engine can’t running smoothly and check engine light on.Technician want to solve this trouble by traditional method: washing oil-way to clear carbon buildup, replacing oil filter fram and spark plug, then clear the trouble code.
After finishing above operations, technicians restart car to test trouble,found several minutes later, the trouble code and symptom of engine shaking vibration appeared again. Technician consulted the schematic diagram of engine running stability, show as below.
According to above schematic diagram,we can get information: ME control module gathering singal from relevant sensors and control fuel-injection quantity accurately to ensure engine running smoothly,combustible mixture is controlled in the range ofλ = j.
Technicians judge below 4 reasons result in engine shaking vibration & check engine light on:
1.Oil-way failure,cylinder 1 oil injector trouble.
2.Ignition system trouble,for example:cylinder 1 spark plug and ignition coil trouble.
3.Relevant circuit wire trouble,for example: circuit trouble of cylinder 1 spark plug,ignition coil or ME.
4.ME control module error.
Technicians serached and found the circuit diagram of oil injector and igniton system showed below.According to the diagram,technicians found oil injector and ignition system powered by 87 circuit.Oil injector actuated by GND signal of ME control module,and ignition coil actuated by the other control signal of ME control module.
In conclusion,check below one by one:
1.Execute guide testing of trouble code(show as below),detect voltage of cylinder 1 ignition coil,it showed 12:Normal!
2.Check the signal circuit of cylinder 1 ignition coil and oil injector to ME control module,found wire connected firmly and conduction performance is normal.
3.Replacing the ignition coil,oil injector and spark plug,but trouble symptom appeared again.
4.Update the software of ME control module,but trouble still exist.Technicians suspect there was a fault on the ME control module firmware.But technician can not repalce ME alone,because ME module fetured anti-theft function.Therefore,leave this problem aside temporarily.
Organize the thought,according to the trouble characteristics,the internal of engine is also need to be check.So technicians removed the spark plug and detected the pressure of cylinder by cylinder pressure gauge,found cylinder pressure is 0 bar,but other 3 cylinder are 12 bar.This pressure data is unnormal,it mean there is a fault in the engine cylinder 1.
Technician removed the cylinder 1 cover, found exhaust valve and valve seat both lack a corner.(showed as below)
Check the cylinder wall and piston,both all them are normal,there are not abnormal wear on the surface on them.Then check ternary catalyst,it is normal!
Solution: Replacing the cylinder head and cylinder pad,then starting car to test,the trouble disappeared.