Summary and cause analysis of common failure cases of Mercedes-Benz models
First, the engine light
Common causes:
1. One or more cylinders are not working properly;
2, a sensor (such as: air flow meter) damage;
3, a certain actuator (such as: fuel nozzle, throttle) damage;
4. Light up due to gearbox or other module failure;
5, the addition of poor quality or excessive impurities caused by gasoline;
6, high pressure pack or high pressure cylinder line leakage, spark plug damage;
General solution:
1, first by the computer to adjust the fault code and then judge to determine what type of fault and whether to replace parts;
2. W221 reports the right exhaust camshaft adjustment error; first replace the improved camshaft adjustment electronic valve; if the same fault is reported, remove the engine and replace the balance shaft;
3, clean the tank, replace the gasoline and gasoline grid.
Two, the engine acceleration is weak
Common causes:
1. The gasoline pump works poorly, the oil circuit is blocked, and the gasoline pressure cannot reach the specified value;
2. Air flowmeter is damaged, throttle valve is dirty or damaged;
3, one or more cylinders do not work or work badly;
4. The exhaust pipe is blocked;
5. Gearbox failure;
6, the spark plug due maintenance;
7. Insufficient cylinder pressure;
General solution:
1. Check the test run first to determine the problem;
2. Replace related accessories such as gasoline pump, gasoline grid, air flowmeter, spark plug, ignition wire, coil, throttle valve, etc.
Three, less engine oil
Common causes:
1, oil maintenance is not enough;
2, the engine oil leakage is very serious;
3. Engine burning oil;
4. The oil and gas separator is bad or the separation chamber is blocked;
General solution:
1, first check how much oil is missing;
2. Check again for oil leakage;
3. Replace the oil and gas separator and repair the oil leak, add good oil and let the owner open for a period of time to check again, if there is less to overhaul.
Four, the idle speed of the engine is unstable
Common causes:
1. Poor ignition;
2, the mixture is too thick or too thin;
3, the throttle is dirty or bad;
4. The oil nozzle is damaged;
5. Air intake system leaks;
6, exhaust is not smooth;
7, cylinder pressure is not enough;
8, the timing is wrong;
9. Excessive carbon accumulation;
General solution:
1. First check and determine the problem;
2. Replace relevant parts and repair other parts of the engine;
3, replace the spark plug, gasoline grid, ignition coil, cleaning or replacing the nozzle, cleaning or replacing the throttle, cleaning the intake valve carbon, etc.
Five, the front of the engine abnormal sound
Common causes:
1. Engine belt aging, belt tensioner weak or tension wheel abnormal sound;
2, belt transition wheel abnormal sound;
3, direction machine, air conditioning pump, water pump, generator bearing abnormal sound;
General solution:
1. Replace the engine belt tensioner;
2. Replace the belt transition wheel with abnormal sound;
3, replace the direction machine, air conditioning pump, water pump, generator bearing.
Six, the engine internal abnormal sound
Common causes:
1. Abnormal sound of valve;
2, the chain plate abnormal sound;
3, engine cylinder knock;
4, the chain tensioner abnormal sound;
5, oil circuit pressure is low or blocked;
6, oil quality is not qualified;
General solution:
1, first check to determine the sound location and oil quantity, oil quality;
2. Disassemble and inspect local parts when necessary;
3. Replace valve tappet or chain plate or timing tensioner;
4. Engine disassembly and inspection overhaul.
Seven, the engine belt is broken
Common causes:
1. Engine belt aging;
2, a wheel deformation or model is wrong;
3, a bearing is locked (such as generator, transition wheel);
General solution:
1. Replace the engine belt;
2. Replace a deformed wheel or a wheel with the wrong model;
3. Replace the parts (such as generators and transition wheels) that are locked by bearings.
8. There are screams after the engine starts
Common causes:
1, the belt aging or too long;
2. Loose belt tensioner is weak;
3, a wheel deformation;
General solution:
1. Replace the belt and belt tensioner;
2. Replace the wheel (such as the water pump wheel).
Nine, the engine does not start or start but does not fire
Common causes:
1. The car key is broken;
2. The battery has no electricity;
3. The starting motor is broken;
4. Anti-theft is not unlocked;
5. Failure of starting system (such as gear switch);
6, the engine electronic control system has a fault (such as crankshaft position sensor);
7, the gasoline pump does not work.
General solution:
1. Overhaul/replace car keys;
2, check the vehicle power generation and whether there is leakage;
3. Check and repair the trailer in the factory and replace the relevant accessories, such as battery starting motor, starter and bending position sensor.
Ten, the engine cold car is not good to start
Common causes:
1. Throttle valve is too dirty or damaged;
2, water temperature sensor damage or line fault 3, gasoline pressure regulator damage;
4, gasoline pump pressure relief;
5, the intake valve carbon deposit is serious;
6. Camshaft position sensor or other sensors fail;
7, the mixture is too thin or too thick;
General solution:
1. Clean or replace the throttle valve;
2. Replace water temperature and other sensors or repair lines;
3, replace the oil pressure regulator or gasoline grid (with regulator);
4, replace the gasoline pump;
5. Disassemble and install the intake manifold to clean carbon;
6. Replace the camshaft position sensor or other sensors;
7, check the reason of too thick or too thin and repair.
It is difficult to start a car with a hot engine
Common causes:
1. Throttle valve is too dirty or damaged;
2, oil pressure regulator oil infiltration or pressure relief;
3. Oil leakage and pressure relief of the nozzle;
4, gasoline pump pressure relief;
General solution:
1. Clean or replace the throttle valve;
2, replace the oil pressure regulator or gasoline grid (with regulator);
3, clean or replace the nozzle;
4. Replace the gasoline pump.
Twelve, the engine water temperature is too low
Common causes:
1, thermostat open too early or circuit failure;
2, the engine is not equipped with thermostat;
General solution:
1. Replace the thermostat.
Thirteen, the engine water temperature is too high
Common causes:
1, thermostat can not open or open enough;
2. The coupling is weak;
3, electronic fan does not turn or speed is not enough;
4, the battery power is not enough (the generator does not generate electricity);
5, less water tank, water system leakage phenomenon;
6, the pump is bad or the pump belt loose, broken;
7, the water temperature sensor is bad or the line is faulty, the instrument display is not correct.
Fourteen, less water tank, water level light
Common causes:
1. Water tank cover leaks;
2, water pipe system leakage;
3. Water tank and auxiliary kettle leak;
4, warm water tank leakage;
5. The middle cylinder pad is leaking;
6, a long time without the natural loss of water tank;
7. Damaged water tank or wiper water level sensor;
General solution:
1. Check the leaking part and replace the water system such as the auxiliary kettle, water tank, water pump and water pipe;
2, check the periphery if no water leakage, then replace the water tank cover;
3. If the cylinder pressure is insufficient, lift the cylinder and replace the relevant auxiliary parts;
4. Replace the water level sensor or auxiliary kettle.
Fifteen, the oil light
Common causes:
1. Low pressure of electric and mechanical pump and damage of oil pump;
2. Oil circuit pressure relief;
3. Oil pressure sensor or line failure;
4, oil quality is not qualified;
General solution:
1. Replacement oil pump;
2. Dismantle, inspect and overhaul the engine;
3. Replace the oil pressure sensor or repair the line;
4. Change the oil.
16. Generator light on
Common causes:
1, the generator generation is too high, the generator regulator is damaged;
2, the generator does not generate electricity, the generator is bad;
3, the generator does not generate power, no 61 signal line;
4. The generator belt is broken or the tensioner is weak;
5, the generator generation monitoring signal is interrupted;
General solution:
1. Replace the generator regulator;
2. Replace the generator;
3. Replace the generator belt;
4. Check and repair generator signals.
17, gear body vibration
Common causes:
1. One or more cylinders are not working properly;
2. Throttle valve dirty;
3. The foot glue and the wave box bracket glue sink;
General solution:
1. Check whether the engine works smoothly;
2. Clean throttle valve;
3. Change the foot glue and wave box bracket glue.
18. The impact of shift shift is large, and the engine speed increases suddenly when shift shift
Common causes:
1. The rubber cake of the drive shaft is broken and loose;
2, differential gap is too large;
3. Transmission thrust into gear;
4. Gear box is not in good gear, slipping;
General solution:
1. Replace the rubber cake of the drive shaft;
2. Replace the differential;
3. Maintenance of transmission;
4, replace the valve body or computer and programming.
19. The steering wheel shakes when driving about 80 yards
Common causes:
1, the tire is not balanced properly;
2. Steel ring deformation;
3. Body chassis parts are damaged;
4, there is water or other things in the tire;
General solution:
1, tire dynamic balance;
2. Replace the deformed steel ring;
3. Replace the body chassis parts;
4. Remove and install tires.
20. When driving about 120 yards, the chassis of the car body shakes or a common shock is felt
Common causes:
1, the tire is not balanced properly;
2. Steel ring deformation;
3. Body chassis parts are damaged;
4. The drive shaft or half shaft is abnormal;
5. Overbridge bearing and seat of the drive shaft are damaged;
6, there is water or other things in the tire;
General solution:
1, tire dynamic balance;
2. Replace the deformed steel ring;
3. Replace the body chassis parts;
4. Replace the drive shaft or half shaft;
5. Replace the bridge bearing and seat;
6. Remove and install tires.
21. The car body starts to shake after driving 30/40 yards
Common causes:
1. Car tires are seriously worn or deformed;
2. Steel ring deformation;
3. Tire screws or other chassis screws are not tightened;
General solution:
1. Replace deformed tires or steel rings;
2. Check relevant chassis parts and do four-wheel positioning;
3. Tighten the screws.
22. Brake steering wheel shakes during driving
Common causes:
1. Brake disc deformation;
2. Body chassis parts are damaged;
General solution:
1. Replace the brake disc;
2. Replace the chassis parts of the body.
23. Abnormal sound of chassis on rotten road/driving
Common causes:
1, body chassis parts loose as ball head;
2. Abnormal sound of body shock absorber;
3, C, E before the top reducer rubber rot;
4, the front balance rod glue abnormal sound;
5. There are sundries in the engine room or tail box;
General solution:
1. Replace the body chassis parts;
2. Replace the shock absorber;
3. Reduce the top glue before replacement;
4. W220 needs to replace the whole balance pole;
5. Check for debris.
24, high-speed traffic abnormal sound
Common causes:
1, the car tire unilateral wear, tread uneven;
2. Inaccurate positioning data of four wheels and incorrect front beam;
3, wheel bearing or drive shaft bearing abnormal noise;
4, differential abnormal sound;
5. There are foreign bodies in the wheel or transmission system;
General solution:
1, replace the tire, and check the replacement chassis parts for four-wheel positioning;
2. Replace abnormal bearings;
3. Replace the differential;
4. Check the wheel or transmission system.
Twenty-five, in situ to hit the direction of abnormal sound
Common causes:
1, the direction of the left and right have the ring of clunking;
2, to the left is about to play in the end when a sound;
3, around the direction of the rattle rattle sound;
4, around the direction of sand sand sound;
General solution:
1. The bottom plate screws under the body are loosened to replace the bottom plate screws;
2, direction machine abnormal sound (W220 common disease);
3, replace the chassis ball head (anti-tip sleeve rotten or no oil caused);
4, lubrication steering column, steering knuckle dust jacket.
