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C240 Gas Mileage Problems and Others

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C240 Gas Mileage Problems and Others

 
Old 03-08-2013, 08:46 PM
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2002 c240
C240 Gas Mileage Problems and Others

Hello everyone. My name is Abe. Ive lurked the forums for a while but this is the first time im posting..

I have a 2002 C240 that i just purchased. It is my second Mercedes, my first being a 2006 C230.

I was hoping to get some guidance on a few issues i have been having.

My gas mileage is so bad i am considering selling the car. I am getting 220 miles to a full tank of gas with a combination of city and highway driving. I live in a very small town so i dont really consider the type of driving i do to be cityish. The car when accelerating sort of hesitates or sputters, almost feels like a shift but not as hard. It idles kind of rough but im not sure if thats cause the engine is running hard of if the tranny or engines mounts need some help but either way the gas mileage is killing me. I have changed out all the spark plugs already and checked to see if it has codes. There is no codes that would relate to the engine. I do have some body codes that would have no affect that i have to deal with. The only code that i do have is p2000 brake pressure implausible but i saw a star service bulletin that on some models of my car that the particular code can not be cleared and is not an issue. I am stumped on what to do. I have talked to a mechanic who assures me over and over again that if i had an EGR valve issue that it would throw a code and so would the fuel pump or any vacuum leaks or anything related to the O2 sensors as well as clogged cats because the emission system is very sensitive. I have access to a scan tool and all tools that would be needed to diagnose the issue but i do not know where to start. i was going to look at the fuel trims but i do not know where to begin on that either. If someone could please give me a hand on where to start id be very appreciative.

Thanks guys,
Abe
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Old 03-08-2013, 09:45 PM
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2005 c230 kompressor 2003 s500 94 wrangler
miles? did u have this car hooked up to SDS before purchasing? this is what u need to do.

need more info
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Old 03-08-2013, 09:54 PM
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2002 c240
106K and no i did not hook it up to a SDS. I have been using a Solus Ultra and that is what i have been reading the codes with.
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Old 03-08-2013, 11:18 PM
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2002 c240
I have the same car. I usually fill back up at around 1/8th left, and I would have 190-220 miles on the tank. I would say it's 90% city...10 miles per day, basically. as for a "rough" idling, I don't feel that. You probably want to get that checked out. Make sure your using premium gas? I don't think that could cause it, but.. never know.
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Old 03-09-2013, 12:05 AM
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2005 c230 kompressor 2003 s500 94 wrangler
bottom line u need SDS to diagnose that check engine

that check engine light will decrease your mileage no matter what....its having u run rich

once that is completed look at thse
tires? alignment? spark plugs? wires? coil packs?
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Old 03-09-2013, 10:34 AM
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late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
The Snap On Solus Ultra can pretty much diagnose most of what a Star can do.

Are you getting any fuel trim codes or misfires. Most C240's of your age need new plug wires & sometimes the odd coil pack. MAF and throttle body clean are also recommended. How old are the 12 plugs? I have recently sold an 8 year old C240 that I owned from new. Fuel consumption was not bad but not as good as 4 cylinder models obviouly. Mine used to average about 9.3 litres/100 km once warmed up.(25.3 US MPG) in urban, extra urban driving. Better on the open road. Your idle should be perfect.

The OBDII port is below the steering column under an oblong flap. Read stored codes & post them. We will help you.

Last edited by Glyn M Ruck; 03-10-2013 at 07:27 PM.
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Old 03-10-2013, 06:41 PM
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Just as a comparison: 2002 C240 7miles*2 of urban driving daily = 18mpg.
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Old 03-10-2013, 07:28 PM
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late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Yes ~ that would be typical on such a short trip. The vehicle is running open loop enriched mixture for half the distance.
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Old 03-10-2013, 08:06 PM
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c240
my son drives 3 miles to college and back every day, some days make the trip twice. MPG is 16.5 constant each fill-up.
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Old 03-12-2013, 06:21 PM
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Originally Posted by Glyn M Ruck View Post
The Snap On Solus Ultra can pretty much diagnose most of what a Star can do.

Are you getting any fuel trim codes or misfires. Most C240's of your age need new plug wires & sometimes the odd coil pack. MAF and throttle body clean are also recommended. How old are the 12 plugs? I have recently sold an 8 year old C240 that I owned from new. Fuel consumption was not bad but not as good as 4 cylinder models obviouly. Mine used to average about 9.3 litres/100 km once warmed up.(25.3 US MPG) in urban, extra urban driving. Better on the open road. Your idle should be perfect.

The OBDII port is below the steering column under an oblong flap. Read stored codes & post them. We will help you.
I did replace all the plugs but not the wires about a week or so ago. Ill take your advice and clean the MAF and throttle body. Do you know what a normal fuel trim would be and where i can find it on the SOLUS?

Here are the codes.
P2000 Brake Pressure Implausible
B11D Fault in CAN communication with control unit N22 (AAAC push button control module) the fault code B110D appears with out any complaints or problems
B1121 Over Voltage
B1003 Voltage Supply Low
B15A8 Component M2/15 (left and right footwell flaps actuator) is stiff or blocked
B100 Normalizing of the positioning motors is not okay. one or several positioning motors are faulty or normalizing has not been carried out.

Thanks
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Old 03-12-2013, 07:32 PM
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late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Look up thread called "Climatronic easter egg" & do an HVAC controller reset. After that cancel all codes & see what comes back. These Body codes have nothing to do with fuel consumption.

The brake code needs to be watched. It might be nothing. I've never seen a brake code on these cars. When last was your brake fluid changed. Should be done every 2 years.

Is your battery in good order.
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Old 08-17-2016, 04:28 PM
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C240
Horrible MPG

Just bought a 2004 C240, the computer told me I was getting 23.9 MPG- crappy (a car with 2 plugs per cylinder - I would expect high performance), but OK. 2 weeks later it dropped to 20.08. I drive almost entirely highway. Maint. is up to date. Have never seen a car suck gas like this since my antique '72 Volvo.
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Old 08-17-2016, 04:43 PM
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2005 clk55 & 1992 190e sportline
23.9 for a near 4k lb car is not bad. Driving habits could change your MPG that much.

What do i know though i get 17.5 mixed.
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