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Mercedes Benz CLK200 1.8 2004 - EML on, code P201C #

Posted by Colin Cooper on November 12, 2016, 5:06 pm

Year of Manufacture *: 2004
Engine Size and Code *: 1.8kompressor
( Optional ) Scanner Used: Verus pro

Vehicle came in with EML on and report of higher than normal fuel consumption.

So far I've replaced the PCV valve and pipes,
I've smoke tested the whole system-no leaks.
I've checked the wiring loom for oil contamination and I've scoped the MAF which is all within spec.

The O2 sensor is staying constant at 0.98volts at idle then goes to 3.2volts at WOT.
Coolant temp sensor is also working fine.

Emissions test is showing 3.5% CO
But only 200-300ppm HC

Anyone got any ideas?

Re: Mercedes clk200k fault code P201C

Posted by andrew pethig <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on November 13, 2016, 9:35 am, in reply to "Mercedes clk200k fault code P201C"
Andrew Pethig

you say...

The O2 sensor is staying constant at 0.98volts at idle then goes to 3.2volts at WOT.

i think that should be milliamps not volts as the sensor is a wideband sensor

i have seen this co reading a few times with the mercedes and the fix has been a new upstream o2 sensor.

Re: Mercedes clk200k fault code P201C

Posted by Colin Cooper <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3944' width='330' height='300' border=0 style='border:none;'> on November 14, 2016, 7:37 pm, in reply to "Re: Mercedes clk200k fault code P201C"
Colin Cooper

Tried swapping O2 sensor bit the fault is still the same, high CO reading.

Engine runs fine with plenty of power.

STFT is 2
LTFT IS 18.

Re: Mercedes clk200k fault code P201C

Posted by andy pethig <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on November 14, 2016, 8:05 pm, in reply to "Re: Mercedes clk200k fault code P201C"
Andrew Pethig

what is the lambda reading on the gas machine ?

and what does it say on the scan tool ?

Re: Mercedes clk200k fault code P201C

Posted by Colin Cooper <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3944' width='330' height='300' border=0 style='border:none;'> on November 15, 2016, 4:11 am, in reply to "Re: Mercedes clk200k fault code P201C"
Colin Cooper

Lamda is reading 0.875
P201C mixture format self adaptation (fuel trim)

I'm suspecting a leaking injector?

Re: Mercedes clk200k fault code P201C

Posted by Steve Harvey <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5250' width='330' height='300' border=0 style='border:none;'> on November 15, 2016, 6:39 am, in reply to "Re: Mercedes clk200k fault code P201C"
Steve Harvey

Hi Colin,
You say the MAF is "in spec". What are the readings?
Regards Steve Harvey

Re: Mercedes clk200k fault code P201C

Posted by Colin Cooper <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3944' width='330' height='300' border=0 style='border:none;'> on November 15, 2016, 9:32 am, in reply to "Re: Mercedes clk200k fault code P201C"
Colin Cooper

MAF readings are

Idle 0.6 volts
WOT 3.75 volts

Im using the data from the verus

Re: Mercedes clk200k fault code P201C

Posted by Steve Harvey <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5250' width='330' height='300' border=0 style='border:none;'> on November 17, 2016, 6:40 am, in reply to "Re: Mercedes clk200k fault code P201C"
Steve Harvey

Hi Colin,
Have you had any luck with this? I would be looking to replace the MAF.
Regards Steve Harvey

Re: Mercedes clk200k fault code P201C

Posted by Colin Cooper <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3944' width='330' height='300' border=0 style='border:none;'> on November 19, 2016, 1:18 pm, in reply to "Re: Mercedes clk200k fault code P201C"
Colin Cooper

Tried replacing MAF and pre cat O2 sensors to no avail, checked complete loom for oil or water ingress-no faults

Suspecting ECU fault but can't be sure, I feel as though I've checked and double checked everything.

Re: Mercedes clk200k fault code P201C

Posted by andy pethig <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3731' width='330' height='300' border=0 style='border:none;'> on November 19, 2016, 2:48 pm, in reply to "Re: Mercedes clk200k fault code P201C"
Andrew Pethig

colin have you tried a injector balance test ?

you should be able to do it from the scan tool, and a fuel pressure gauge .

this might help tie it down,

what are the gas readings at 2000 rpm. ?

Re: Mercedes clk200k fault code P201C

Posted by Glyn Morgan <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2543' width='330' height='300' border=0 style='border:none;'> on November 19, 2016, 2:55 pm, in reply to "Re: Mercedes clk200k fault code P201C"
Glyn Morgan

Hi Colin

Have you reset adaptions after changing Maf/O2 sensors ?

Regards

Glyn

Re: Mercedes Benz CLK200 1.8 2004 - EML on, code P201C #

Posted by Chanaka Johns <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3992' width='330' height='300' border=0 style='border:none;'> on November 19, 2016, 5:09 pm, in reply to "Mercedes Benz CLK200 1.8 2004 - EML on, code P201C #"
Chanaka Johns

Please Give me.

Maf values
fuel trim values
Lambda Values
PreCat O2 sensor mA value
After Cat O2 sensor Volt

Both at Idle and 2000 rpm and Wot..Lets to some study..

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