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Billy
Billy, Trainer/Master tech.
Category: UK Car
Satisfied Customers: 3498
Experience:  Trainer - master tech., SAE member
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Mercedes-Benz W212 E250 CGI 7G-Tronic: Hi, I drive a W212 2012

Resolved Question:

Hi, I drive a W212 2012 E250 CGI 7 G-Tronic. My mileage is only 15500km. My vehicle dashboard recently flashed engine warning light. I brought it back to the dealer and they diagnosed the error as cylinder 1 & 4 knock limit exceeded. The reset the error but now my vehicle is experiencing intermmitent loss of power and sluggish gear upshift or downshift. What is wrong?
Submitted: 3 years ago.
Category: UK Car
Expert:  Billy replied 3 years ago.

Billy :

Hello and Welcome! I'm Billy and i will assist you with your inquiry. Feel free to ask if any further info is needed.

Billy :

when you get the loss of power (reduced performance), do you get any warning lights or messages?

Billy :

when you had the problem in the first place, they did not replace anything? did not tell you anything about it... bad fuel etc...?

Customer:

I installed a piggy back chip and a throttle device since about 1 year ago. Both are just piggy back systems, plug & play without any cutting, splicing or modification to original ECU. Been driving without any problems for about 14 months. My engine warning light only flashed about 2 days ago. It happened when I was cruising on highway and slowed down , the transmission downshifted and when I sped up again, there was about 1 second delay in upshifting, it alsmost felt that the car was in neutral or idle. Shortly after that the enginer warning light in orange/amber flashed. I brought the car back to the dealer and what i mentioned was diagnosis by the dealer technicians. They reset the error code and asked me to remove both piggy back systems, which I did this morning. I have been driving my car and really trying all sorts of driving conditions to get a good feel. The reduce performance and sluggish gear change since this morning did not result in any warning light or message. Driving up a steep multi-storey car park ramp made the car feel really underpowered, and the car could not downshift normally on steep uphill condition. The dealer technicians only told me that it may be bad fuel, while consulting other third party workshops, others suspect it may be ignition coil, spark plugs, loose connection, dirty or spoilt MAF etc. Should I be worried? I checked the web and found 2 other similar complaints on 2012 E250 W212, one was in Bangladesh and the other in the US. Is this a common problem with 2012 W212? The techs in the local dealer in Singapore are not very qualified and experienced as I have previously encountered when I sent my car in other sound, rattling, suspension and tuning matters. Problems usually take 2-3 visits to the dealer before getting resolved, and that's usually after I helped them pinpoint potential roo causes after reaseaching the web and consulting other owners or workshops. Their first response is usually " that's normal" or " we don't detect anything abnormal" etc. and try to brush complaints aside, until the second or third visis before they start to take things more seriously. Your expert advise and help is very much appreciated. Thanks.

Billy :

Hello,

Billy :

I understand your frustration, as the vehicle is still brand new.

Billy :

Of course the piggy back systems installed are not responsible for the issue you are having. As these were installed for some time, and never gave problems.

Billy :

I have seen some problems with the w212, but it is not recurrent, and for now, no recalls have been issued.

Billy :

The problem indeed could be with the MAF, coils or plugs. However, this would be nothing to worry about, as all these (except for plugs) would be covered by warranty.

Billy :

If you are still getting the reduced performance (you may want to install your chip and throttle back), and try the vehicle, see if you get any problems.

Billy :

If you still get the problems (reduced performance), then the vehicle would need checking using a diagnostics tool (STAR scan tool), when driving it. They should check and monitor the live data of the MAF, air intake, fuel and spark, and this should give an idea, what is causing this.

Billy :

Unfrotunately, the problem, being intermittent, will be hard to trace. However, it will either increase, and then show on the diagnostics (STAR scan tool), or it will go away being a case of bad fuel or just a sporradic error.

Billy :

Bad fuel is really a suspect here, as the codes (knock limit) and the reduced performance are its symptoms.

Billy :

I would try a bottle of octane booster, and fuel tank cleaner, and check further.

Billy :

Kindly get back to me with your findings, or if further assistance is needed, so we proceed accordingly.

Billy :

Thank you for your trust! Get back to me if you need more assistance...Thank you in advance for the positive rating...
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Billy :

Regards, Billy

Billy, Trainer/Master tech.
Category: UK Car
Satisfied Customers: 3498
Experience: Trainer - master tech., SAE member
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