Mercedes Benz
Service A/B/C..., what do they mean?
Mercedes vehicles will display a maintenance warning on your instrument cluster when your vehicle's service is due. This built in system that tracks wear and reminds drivers of their due services is called Assyst (later Assyst Plus, etc).
These warnings have changed throughout the years, going from a simple wrench symbol in the dash, to the Service A (minor) or Service B (major) popping up in you instrument cluster, to the more specific service A/B followed by numbers, which indicate other additional services.
When you bring your car to us for a schedule maintenance to be performed, we will inspect the instrument cluster and determine exactly what services are required, and sometimes modify those to fit your specific needs. It could be that a service warning will show as being due by time but not needing to be done just yet if the mileage is low.
For example the transmission service according to Mercedes should be performed at 120,000km or 6 years, whichever comes first, but
with little driven vehicles this service warning will be prematurely triggered by time instead of mileage. It doesn't make sense to replace the transmission fluid if you have driven your car only 30,000km.
When we asses the need of a certain service, we check your vehicle history and determine appropriate services. Service B includes the replacement of the cabin filter but if the filter is deemed clean upon inspection, then we won't replace it, with your approval of course.
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Service A
The following work is performed during a service A:
- Inspect for any additional services stored in the instrument cluster and write down any additional warning lights/messages
- Change oil and filter
- Reset tire pressures, tire pressure monitor (TPMS) and service reminder, affix oil sticker on the driver's door set at 10,000 km interval
- Lubricate all hood/door/trunk hinges and latches
- Top up all fluids including diesel exhaust fluid where applicable
- Inspect brakes ( record pad thickness in mm), inspect tire condition (record wear in mm)
- Check all steering and suspension components for wear
- check for abnormal leaks and other wear
- road test vehicle
Service B
Service B consists of all the services included in service A with the following extras:
Additional Services
Combined with either service A or B (on older MBs there were other service letters: C, D, E, F, G, H) there are the so called "additional services".
The message in the instrument cluster could be A1, B5, etc.
Service B
Service B consists of all the services included in service A with the following extras:
- Replacement of the cabin filter
- Inspection of the air filter (s) and replacing if dirty (parts extra)
- Rotate tires front to back if needed (1mm wear difference between front and back tires)
- Highway road test (mostly to identify possible high speed malfunctions like wheel balance issue, transmission shifting, etc)
Additional Services
Combined with either service A or B (on older MBs there were other service letters: C, D, E, F, G, H) there are the so called "additional services".
The message in the instrument cluster could be A1, B5, etc.
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Mercedes service numbers description (as they show in the hidden service menu):
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Mercedes Service numbers when combined with additional services:
· A: service 1, 2 · A1: services 1,3,4 · A2: services 1, 3, 4, 10 · A3: services 1, 3, 8, 11 (diesel) · A3: services 1, 3, 8, 12 (gasoline) · A4: services 1, 3, 8, 10, 11 · A5: services 1, 3, 4, 8, 11 · A6: services 1, 3, 4, 8, 11 · A7: services 1, 3, 20 · A8: services 1, 3, 10, 20 · A9: services 1, 3, 4, 20 · A0: services 1, 3, 10 · AC: services 1, 3, 4, 10, 20 · AF: services 1, 3, 4, 8, 12, 20 · AH: services 1, 3, 13, 24 · AG: services 1, 3, 4, 8, 10, 11, 20 · AK: services 1, 3, 13 · B1: services 2, 3, 4 · B2: services 2, 3, 4, 10 · B3: services 2, 3, 8, 11 · B4: services 2, 3, 8, 10, 11 · B5: services 2, 3, 4, 8, 11 · B6: services 2, 3, 4, 8, 10, 11 · B7: services 2, 3, 15, 20 · B8: services 2, 3, 10, 20 · B9: services 2, 3, 4, 20 · B0 - 1607: services 2, 3, 8 · B0 – 906F: services 2, 3, 8, 10 (AMG) · BD: services 2, 3, 8, 11, 20 · BE: services 2, 3, 8, 10, 11, 20 · BK – 10E0F: services 2, 3, 4, 14 · BK – 14E0K: services 2, 3, 4, 11, 13 BS: services 2, 3, 10, 13, 20 |
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Spark plug replacement
One of the most common maintenance service and also essential to have done in time because if neglected it can lead to major issues, misfires, further damage to the catalytic converters and ultimately you can end up on the back of a tow truck. Usually done around the 100,000km mark, the first signs of excessive spark plug wear is a rough idle running especially at startup in cold weather. Initially it will not trigger any engine light faults but if ignored it will lead to misfire and possibly reduced engine output. We only use OEM original spark plugs, NGK or Bosch, depending on Mercedes Benz recommendation. AMG vehicles will require the spark plugs replacement sooner, between 50,000km to 75,000km depending on the model. |
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Air filter and cabin filter replacement
The air and cabin filters are replaced usually between 30,000km and 50,000km depending on the condition. Excessive clogging of the air filter will lead to reduced performance and fuel economy, and if really bad will trigger an engine light. It should be checked every two years or 30,000km. The cabin filter is responsible for filtering the air inside the car as the name suggests. Some Mercedes Benz vehicles have two cabin filters, one also called a dust filter or pre-filter. Neglect can lead to reduced air flow at the vents, extra strain on the blower motor and sometimes foul smell in the cabin. Most cabin filer are charcoal activated, meaning they are efficiently filtering out the carbon monoxide coming from the surrounding vehicles. Purflux, Mann, Mahle and Hengst are our preffered OEM brands for filters. |
Brake service
Under normal condition, the brakes will last somewhere between 40,000km and 60.000km. Mercedes Benz vehicles are equipped with sensors that will warn you when your brakes need service. When the pads are worn out there will be either an exclamation mark in the instrument cluster for the older models, or a message informing the driver that the brakes will need servicing.
There will be a grace time period from the time the brake warning is set which gives you about a month or so before the brakes pads' lining will completely wear off. If you hear a grinding noise while applying the brakes, that means that you have exceeded the grace time period to service your brakes. It is UNSAFE to drive with grinding brakes as this will quickly overheat the brake fluid which can and WILL lead to a total loss of brake ability due to vapors in the brake system. It's best to have your vehicle towed to the repair facility when you experience brake grinding noise.
When servicing the brakes it is imperative that the rotors will be replaced along with the pads/sensors. The rotors wear down just like the pads and will become thinner, their face will sometimes become scored, hot spotted or rust pitted. We can install just pads at your request but we shall be liable free of any brake noise, brake pedal pulsation, performance and premature wear (voids warranty).
Ontario's excessive salt conditioning of the roads in the cold weather leads to premature wear of the brakes and for prolonged life we recommend a service every two years even if your brake pads aren't worn out. This is especially useful with vehicles that are driven under 10,000km a year. This service entails removing of all the brake pads and rotors and cleaning off the brake pads' brackets (usually a lot of rust), wheels' hubs, lubricate everything and putting everything back together. This includes servicing the parking brake, cleaning of the adjuster and shoes' contact points, and finally adjusting the parking brake. This is the same service we provide when we replace the worn out brakes but without the parts.
The road salt and the rust that it causes can prevent the pads sliding in their brackets, can seize up the calipers' sliders or the parking brake adjuster, shoes and/or cam mechanism. All of these conditions will lead to uneven and premature wear and degradation of braking performance. We use OEM top of the line parts like Brembo, ATE, TRW, Textar, and Zimmerman just to name a few of the brands. Upon completion, the brake monitoring system will have to be reset.
Under normal condition, the brakes will last somewhere between 40,000km and 60.000km. Mercedes Benz vehicles are equipped with sensors that will warn you when your brakes need service. When the pads are worn out there will be either an exclamation mark in the instrument cluster for the older models, or a message informing the driver that the brakes will need servicing.
There will be a grace time period from the time the brake warning is set which gives you about a month or so before the brakes pads' lining will completely wear off. If you hear a grinding noise while applying the brakes, that means that you have exceeded the grace time period to service your brakes. It is UNSAFE to drive with grinding brakes as this will quickly overheat the brake fluid which can and WILL lead to a total loss of brake ability due to vapors in the brake system. It's best to have your vehicle towed to the repair facility when you experience brake grinding noise.
When servicing the brakes it is imperative that the rotors will be replaced along with the pads/sensors. The rotors wear down just like the pads and will become thinner, their face will sometimes become scored, hot spotted or rust pitted. We can install just pads at your request but we shall be liable free of any brake noise, brake pedal pulsation, performance and premature wear (voids warranty).
Ontario's excessive salt conditioning of the roads in the cold weather leads to premature wear of the brakes and for prolonged life we recommend a service every two years even if your brake pads aren't worn out. This is especially useful with vehicles that are driven under 10,000km a year. This service entails removing of all the brake pads and rotors and cleaning off the brake pads' brackets (usually a lot of rust), wheels' hubs, lubricate everything and putting everything back together. This includes servicing the parking brake, cleaning of the adjuster and shoes' contact points, and finally adjusting the parking brake. This is the same service we provide when we replace the worn out brakes but without the parts.
The road salt and the rust that it causes can prevent the pads sliding in their brackets, can seize up the calipers' sliders or the parking brake adjuster, shoes and/or cam mechanism. All of these conditions will lead to uneven and premature wear and degradation of braking performance. We use OEM top of the line parts like Brembo, ATE, TRW, Textar, and Zimmerman just to name a few of the brands. Upon completion, the brake monitoring system will have to be reset.
Brake fluid flush
Brake fluid flush is recommended to be done every two years, and that applies to all European vehicles. BMW will trigger a service message when brake fluid is due, and will have to be reset upon service completion. Due to its chemical nature, brake fluid attracts moisture (hygroscopy) and the fluid's reservoir is not fully sealed, thus contaminating the fluid over time. Moisture will also lead to the corrosion of the brake lines and an very old fluid, the color is changed to dark brown indicating advance contamination. The presence of moisture not only causes wear in the brake system (calipers, cylinders and the ABS pump/valves) but it also lowers the boiling point, making the brakes more susceptible to fail under heavy braking condition (brake fade). It's a relatively inexpensive service and when combined with an oil service it's even less costly. |
The image above shows the brake fluid being flushed using an industrial bleeder will pump clean brake fluid in the entire brake system.
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Transmission, transfer case, differential service
All fluids in a vehicle change and wear overtime, the transmission, t-case and diff's oils even more so given the harsh environment these oils operate in. Usually neglected or put off, not changing the fluid in the transmission, transfer case and differentials usually leads to very costly repairs. Mercedes Benz recommends transmission service (service 20) to be performed between 60,000km (on older vehicles with the red fluid) to every 120,000km for the newer vehicles with the blue fluid in the transmission. During the transmission service, the fluid, filter, oil pan gasket and sometimes the pan bolts if they are aluminum, are replaced. Fluid level is checked at operating temperatures of around 50 Celsius degrees, and a road test is performed afterwards. Transfer case fluid - between 150,000km and 200,000km unless t-case exhibits abnormal/faulty behavior. The C Class Mercedes (W204 body style) is known for transfer case failures due to transmission services not being performed. In this model, the transfer case uses the same fluid as the transmission and the repairs/overhauling are usually expensive, certainly a lot more expensive than a transmission/t-case service. Front and rear differential - 150,000km to 250,000km depending on model, unless diff is noisy ore exhibits abnormal operation (shudders in turns, noisy). The valve body, torque converter, gears, fluids, all wear down over time and fresh lubricant will prolong the life of your transmission, transfer case or differential. Waiting for transmission, transfer case or diff problems to happen will usually lead to expensive repairs and long downtimes. |
Rear differential fluid change
The two magnets collect the wear particle from the transmission components and are being cleaned during the transmission service.
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Clean transmission pan, ready to be installed during a transmission service
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Transfer case damage on a C Class Mercedes Benz (W204)
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Mercedes Benz diesel engines
Mercedes Benz is using diesel engines in its E Class, S Class, ML Class, GL Class and Sprinter vehicles. Whether the V6 or four inline, these engines have set the benchmark for diesels in terms of emissions, quietness, fuel economy and power.
In addition to the gasoline counterparts, the diesel engines' maintenance differs slightly, in that the fuel filter is required to be replaced every 50,000km and the Adblue diesels will need the diesel fluid topped up at every oil change. Usually about a liter of diesel fluid (Adblue) is consumed per every 1000km.
Running your engine without it will at first trigger a warning and if not address you'll face the "15 starts remaining" in the instrument cluster message. Don't ignore the adblue warning symbol in your cluster because eventually your car won't start up! Emission components in modern diesels will gradually wear off and will need repairs at higher mileage.
Of great importance in maintaining your DPF (Diesel Particulate Filter) problem free is using low ash engine oils, specifically engineered for diesel engines and use Ultra Low Sulphur gasoline whenever you can. Periodic highway drives are recommended in order to trigger a DPF regeneration. Often times if you experience loss of power, the cause is the DPF being clogged up.
Here at German Automotive we have a great experience and knowledge when it comes to maintaining and repairing your diesel powered Mercedes Benz.
Common Diesel engine failures and repairs
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DPF clogging, loss of power, engine light on A diesel particulate filter (DPF) should last anywhere between 250,000km and 350,000km depending on the driving style. A mainly city driving (short trips) will reduce the life of your DPF and sometimes will cause premature failure/clogging. If the degree of contamination is not excessive due to faulty components or lack of highway driving, the DPF will self-clean ("regenerate"). If components that insure the correct monitoring and functioning of the DPF are faulty and ignored, it could lead to DPF clogging, usually experienced by loss of power and warnings in the instrument cluster. |
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Excessive clogging will require the replacement of the DPF (very costly) but often times moderate contamination can be cleaned out by using chemicals and specific procedures. Liqui Moly in addition to oils, provides us with a cost effective DPF cleaning solution. The whole cleaning procedure takes between 2-3 hours. Specialized diagnostic equipment is needed for monitoring and resetting the DPF learned values.
Oil leaks (oil cooler, oil filter housing, vacuum pump)
One of the most common oil leaks in the V6 diesel engine (OM642) is the infamous oil cooler. The gaskets in the oil cooler gradually loose their ability to seal due to age/shrinkage and will cause oil leaks at the back of the engine. The repair is labor intensive as it requires removal of the intake manifolds and turbocharger. Usually the oil cooler will start leaking at around 100,000km mark, and it's common to have to do this repair more than once during ownership.
We perform a carbon cleaning (extra time) of the intake ports and manifolds during this repair if carbon build up is excessive. This restores some of the lost power caused by intake air flow restrictions.
All the gaskets are being replaced during the repair, and our technicians have done this job numerous times, giving you the peace of mind of a job done right.
The oil cooler gaskets have been updated with purple ones but even those will eventually start to leak
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Intake manifold carbon build up, before and after cleaning
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Oil filter housing (OFH) and the Vacuum pump are also very common to leak at their gaskets and will lead to the contamination of the drive belt and its eventual demise. In the picture to the right you can see the whole oil filter housing being replaced since one gasket (in the middle of the housing) isn't available separately. In the picture below you can see the mess caused by neglected leaky OFH and vacuum pump. 
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Timing chain failure
Some engine experience issues with the timing chains. The older M272/M273 engines and the newer M274 engines have exhibited timing chain related issues. On the M272The OM642 diesel also has a chain stretching problem on some engines.
M272/M273 engines
The Mercedes-Benz M272 engine, particularly those built between 2004 and 2008, is known for a common issue: premature wear of the balance shaft gears, which can lead to various problems including rough idling, misfires, and engine stalling. The V8, M273 suffers from the wear of the same balancer shaft but in this case the gear can be replaced easier since it's at the front and not part of the balance shaft like in the M272.
In the M272 case, the whole engine needs removing in order to replace the worn out balancer shaft whereas the M273 requires the removal of the front timing covers in order to gain access to the balancer shaft sprocket/gear. We've performed both those jobs here and we can provide you with a competitive estimate and 2 year warranty on parts and one year for labor (just like the dealer).
Worn out balancer gear on a M272 engine (image copied from the MB TSB)
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Stretched timing chain, comparison with a new timing chain.
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OM642 engine The diesel V6 engines that develop chain stretch will rattle when first started. On later wear stages, they will run rough, trigger engine lights and possibly caused further engine damage if chain isn't replaced in time. The procedure of replacing the chain on the OM642 is ingenious and it is pulled in with the help the old chain thus greatly reducing labor time. The chain tensioner is also being replaced at the same time. The whole procedure takes about 6-7 hours and it involves removing of the right valve cover. See the picture to the right for illustration. M274 engine While known for its robust design, the M274 engine can experience timing chain issues, including stretching, noise, and potential failure, often due to improper maintenance or oil quality. Symptoms of a failing M274 timing chain include:
At German Automotive we have the special tools and expertise to deal efficiently with all of Mercedes Benz engine problems |
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