Using EOBD code readers with Merc ?

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The engine management light came on the other night on my C270 , along with the usual drop into 'limp mode' .

After restarting 3 or 4 times it would reset and drive normally for a short distance before the fault would come on again .

I felt the most likely culprit was the MAF , but not being 100% sure , I opted for the cheaper alternative one from ECP . After fitting this last night , I was able to clear the fault and the car drove several miles before the fault came on again .

It may be that the cheaper MAF is not a suitable replacement , or it may be there is something else wrong ( I will check for leaks on the induction side over the weekend ) , but in any case some means of diagnosis would be beneficial .

While I could go along and pay someone to plug the car into Star and tell me what is wrong , I'm thinking that there are lots of DIY EOBD diagnostic tools out there , available at a modest cost , which would also work on the various other cars in the family besides my C270 ( my older cars wouldn't benefit ) . While I would not expect the same level of detail or functionality as a Star machine gives ( it would not be reasonable to expect the same of a generic £100 tool as from a dedicated tool costing several thousands ) I would hope that it might be sufficient to point me in the right direction for DIY repairs .

Has anyone on here used any of the generic EOBD fault readers ( such as Gunson , Laser , Sealy etc ) on Mercedes cars , and how much use did they find them ?
 
I have a ELM327 bluetooth reader teamed up with Torque (mobile app) which is OK for engine codes. Anything else I have to whip out SDS. Never tried anything else really
 
I used a cheap and cheerful Maxiscan MS309 which cost me the best part of £20. It was good at generic codes but took a lot of internet research to work out the true cause of the issues. Worked well on the SL and our other cars.

I then invested in an ELM327 and the Torque pro app which gave a bit more info and realtime data. On the W221 I used it to diagnose a faulty differential pressure sensor and O2 sensor which when replaced resolved the limp mode.

See PM
 
Thanks all .

I have ordered an ELM 327 and downloaded the free torque app for my iPhone ( with the option to upgrade to Pro for a further £10-odds ) .

We also have a Samsung Galaxy Android tablet in the house , along with a couple of iPads , so have other devices it can be used with .

At lunchtime I popped down to Halfords and bought cans of electrical contact cleaner and EGR valve/air mass sensor cleaner , so will try cleaning the original MB branded MAF and putting it back in .

Maybe the cheap MAF's are no good , but I'd be surprised at a reputable retailer like ECP carrying them if that was the case ?

Incidentally , it was dark when I did the job last night - could I have put the new one in back to front or anything ? There was no obvious key to make it fit only one way .
 
Derek

When using Torque I got a lot of vague or initially misleading code descriptions but googling the PXXXX code and car model or engine number often threw up someone else with the same issue. That made it easier to fix on mine. If you don't get anywhere, the PM offer is still open, just ping me a PM response.
Good luck
Robert
 
Thanks all .

I have ordered an ELM 327 and downloaded the free torque app for my iPhone ( with the option to upgrade to Pro for a further £10-odds ) .

We also have a Samsung Galaxy Android tablet in the house , along with a couple of iPads , so have other devices it can be used with .

At lunchtime I popped down to Halfords and bought cans of electrical contact cleaner and EGR valve/air mass sensor cleaner , so will try cleaning the original MB branded MAF and putting it back in .

Maybe the cheap MAF's are no good , but I'd be surprised at a reputable retailer like ECP carrying them if that was the case ?

Incidentally , it was dark when I did the job last night - could I have put the new one in back to front or anything ? There was no obvious key to make it fit only one way .

Oh they do.

All of the cheap MAF's do not work properly. Get A PROPER MAF. Cleaning it doesn't work to well either.
 
I have ordered an ELM 327 and downloaded the free torque app for my iPhone
IIRC the highly regarded "Torque" applications require an Android platform rather than an iOS device.
Be aware also that the majority of ELM327 based scanner/readers use 'Bluetooth', to communicate - iOS devices need a (you've guessed it, more expensive) Wifi variant.

Regards, lim
 
Maybe the cheap MAF's are no good , but I'd be surprised at a reputable retailer like ECP carrying them if that was the case ?

LMAO... :D :crazy:


The fault sounds like the EGR valve is either not working or is sticking.
 
IIRC the highly regarded "Torque" applications require an Android platform rather than an iOS device.
Be aware also that the majority of ELM327 based scanner/readers use 'Bluetooth', to communicate - iOS devices need a (you've guessed it, more expensive) Wifi variant.

Regards, lim

Yes , I noticed the wi-FI variant when I followed the link , and ordered the appropriate one , at a whopping £13.99 !

Yes , Torque is available in the Apple App Store , that is where I downloaded the free version , for now . There is also a Pro version available at £10-odds , which I may try once I see how the free version works .

We do have a Samsung Galaxy tablet in the house ( SWMBO's ) which I could have used , but when I saw the iOS version was available and found the app , I opted for that version .
 
LMAO... :D :crazy:


The fault sounds like the EGR valve is either not working or is sticking.

Thanks for the tip :thumb:

I'm going to wait for the diagnostic tool before throwing any more parts at it .

When it first started happening , earlier in the week , the fault would come on either within a few seconds of starting the engine , or within a few yards of moving off .

The fault will always reset by stopping / restarting three times .

After fitting the after market MAF , I was able to drive several miles before the fault would occur .

This morning , I cleaned out the original , genuine MB , MAF using the tin of Wynn's cleaning solvent I bought from Halfords ( described on the tin as EGR valve cleaning solvent funnily enough ) , then let it soak in a jar of petrol for a while before blowing it through with compressed air .

While it was out , I had a look at the various hoses connecting the turbo to the air box and breather : they were generally quite dirty and sooty , I guess due to their location , but I took them off and cleaned them up . There were a couple of burn marks on the sleeve over the breather hose , but otherwise no visible damage . A squirt of the cleaning solvent through it washed a lot of black gunge out of the breather hose , and I cleaned up the electrical contacts to the small sensor at the bottom end .

On building it back up , and refitting the original , cleaned , MAF , I was able to drive several miles before the fault returned .

The car had been sitting for roughly six months while I used the 190 over the summer , only being started and idled on the drive once a month or so , so I suppose a sticky EGR valve is a possibility . After starting to use it again , I had been running it for about a month , doing my daily commute of 34 miles each way ( not driving particularly hard ) , and with a few longer journeys in the mix - I'd have thought enough to get the valve to regenerate ? Maybe I'll need to remove it and try cleaning , or replace if it looks bad when I take it out ... ( I did have a sticking EGR valve on one of the works vans a while back and the symptoms were not dissimilar ) .

After clearing the fault this morning , and with the car running freely , I did take it for a blast up some of the country roads to give it an 'Italian Tune Up' - it was after this that the fault returned .

Even in so called 'limp mode' the car is still driveable , so I'll put up with it for a few days until the OBD tool arrives and see if it gives me any more pointers .

I have some leave days to use in a week's time , so I will have another go at it then .

Thanks so far for all the ideas .

The car is due a B service in about 1000 miles , so I would have been working on it anyway - only other planned job being to change the thermostat before winter as it is slow to warm up and seems to run cool anyway .
 
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This morning I had a PM asking about the iOS version of the ELM 327 and the Apple version of the software .

The Wi-Fi version of the ELM 327 can be found by following Chris's link in post 6 of this thread , then clicking on 'other items' when you get to the seller's eBay listing .

I found the iOS version of the app simply by typing 'Torque' into the search tool in the App Store on my iPhone . It can also be found in the iTunes App Store by the same method .

When you get into the link for the App , there is a link to the developer's website , where there is a lot more info

iPhone/iPad Automobile Diagnostic Application EOBD-Facile

Hope this is of help to others .
 
I got an email this afternoon stating my interface has been despatched by first class post and I should expect delivery tomorrow .

Good service for something ordered over the weekend .
 

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