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Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 - Fixed #

Posted by Simon Forsey on August 3, 2010, 9:47 am

Year of Manufacture *: 1999
Engine Size and Code *: 1900
( Optional ) Scanner Used: Win-Star
( Optional) Fault Codes: P0170 and P0130

Hi

This car has got me running around in circles!

This car is running very rough at idle and at standstill is very reluctant to rev, some times chuffing back through the inlet.

The garage had already changed the throttle body for a 2nd hand one and the O2 sensor had been change for a new one.

DTCs are:-
P0170 Lambda Control : Self adaption is too rich
P0130 O2 sensor upstream TWC. Minimum voltage not reached

I have scoped the O2 sensor and found that it does not switch at either pin 23 or 24 at the ECU, even when I add some hydrocarbons or induce more air into the inlet. When I do add hydrocarbons the engine picks up. [sorry, no gas results available]

Fuel pressure and flow, good.

I have checked the wiring between the O2 sensor and th ECU, and I have tried the original O2 sensor and it is no different.

My question is, do these O2 sensors switch normally between approx 0.1v to approx 0.9v or do these use milli amps? Merc WIS says its the normal switching but I wanted some more advice.

On live readings the O2 control before TWC is 1%, when the system logs the DTCs it changes to 30% and runs a little better in limp.

Any help would be great.

Regards

Simon

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Matt Booth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat3028' width='330' height='300' border=0 style='border:none;'> on August 3, 2010, 11:31 pm, in reply to "Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Could do with a bit more info. You say the probe isn't switching, what voltage is it hanging around?

Both codes are telling you the system is apparently running too rich. I would scope the MAF, I have a strong feeling you'll get a low voltage.

These use a narrowband sensor so you're correct in looking for the old fashion voltage switch. Have you made sure the O2 heater is working ok?

Matt

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Simon Forsey <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5231' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 12:41 am, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Hi Matt

Yes, have checked the heater.

The MAF is part of the ECU within the ducting. Any advice on testing these?

Regards

Simon

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 6:47 pm, in reply to "Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"
Kevin Apps

Simon
Have you done a forum search ? or searched the archives ?
Kev.

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Simon Forsey <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5231' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 8:05 pm, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Hi

Yes I have performed a search of the archives and a forum search [1st thing I always do!]

I have rechecked the O2 readings, flat line @ 400mV Approx. I have re-checked the O2 heater circuit on the scope, this is OK.

If anyone knows how to test the MAF from the ECU board I would be very interested to hear.

I might be having a blond moment but, what else will cause the O2 sensor to flat line? My understanding was that this type of O2 sensor was self generating. So, testing by scope should provide me with some sort of switching if I add additional hydrocarbons or air.

Can I get of this round about yet Dad?!?!?!

Regards

Simon

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 8:28 pm, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Simon.
400mv is default.
Whats the MAF/AMM doing in live data, hundreds of these MAF,s have been re-maned, its very common fault.
Kev.
ps. funny that !! i have just searched and pere roca posted the same codes and a FIX. I knew the FIX was here.

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5535' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 10:01 pm, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"
Alan Kane - Administrator

Kev,

How can there be a default reading on a scope?

Maybe its just me but I often find the archives difficult to search. I have failed in the past to find things that I posted myself. If you have found something in the archives that could help then why not post the link for him?

Cheers

Alan

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Kevin Apps <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2589' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 10:28 pm, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Alan.
I,v been on the go since 4am !! so perhaps i saw what looked like the default figure and thought it was live data !!!. As for it being a scoped figure,perhaps simon can post the capture.

As for the search all i did was put P0170 in the search box above, and the results are there !!!
Kev.
ps i have re-read simon,s post and it suggests he scoped the heater circuit.
Off to bed now !!!

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5535' width='330' height='300' border=0 style='border:none;'> on August 4, 2010, 11:33 pm, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Relax Kev, nobody was having a go.

What you posted was incorrect and could have misled the man. I simply pointed that out. Your P.S. comment is also wrong. He did say he scoped the heater but he also said “ So, testing by scope should provide me with some sort of switching if I add additional hydrocarbons or air.”

I have gone to the trouble of searching the archives to see if I could find the post that you mention. The only one I could find by Pere that is similar was based on a different car with a different system. If you found a different one I would be interested in having a look at it.
The point Kev is, if you have found something in the archives that could help, then there is no point in telling Simon that it exists, while at the same time refusing to help him by not giving him a simple link.
Perhaps you are the all time champion archive searcher and now is your time to shine

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Simon Forsey <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5231' width='330' height='300' border=0 style='border:none;'> on August 5, 2010, 9:05 am, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"

Hi guy

Sorry it wasnt my intention to start a bun fight!

As Alan says, the search engine is not that easy to use. However, I did do a search before starting.

A few further tests, yet another O2 sensor was fitted just in case of a premature failure. We dismantled the ECU and fitted it back in place. The AFM has 11 pins comming onto the board. I scoped these and got what I can only describe a foul patterns, but, I am not sure what I should be seeing so Im not sure if it was a total waste of time. We rechecked the fuel pressure and flow, we also used a Smoke-Pro to check for leaks.

Still going round and round!

Regards

Simon

Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #

Posted by Allan Davis <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1846' width='330' height='300' border=0 style='border:none;'> on August 9, 2010, 7:21 am, in reply to "Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"
Allan Davis

Hi Simon
Last Wednesday i diagnosed the same fault on an A140 for a Mercedes specialist local to me. It had failed the mot for very high co and hc's.As suggested in previous posts it sounds like the maf sensor, luckily enough we had another A class to compare maf readings to. If you want i will get the compared readings for you and post them later but please note this one is an A140 and not the 190 that you have, so the readings will be slightly different.
Allan

Fixed #

Posted by Simon Forsey on August 12, 2010, 2:00 am, in reply to "Re: Mercedes Benz A190 1999 - Rough running, EML on, codes P0170 & P0130 #"
Message modified by board administrator August 12, 2010, 2:59 pm

Hi Guys

After checking everything else was in order. We has a replacement MAF fitted. All is OK now.

Many thanks for all your help.

Simon

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