baro Kpa

[10seventy1]

Hi guys, new here so go easy on me plz... I’ll start with the car details. E350 Cdi auto w207 2009 showing 128000 miles.
After spending nearly a £1000 with my local main dealer on diagnostics and a new Maf New system, For them only to tell me I need a new Ecu as well Another £900, but when I asked if that would cure the fault they simply couldn’t guarantee it. The fault is a boost pressure one but exists right from ignition ON before you even start the engine. The two pressure sensors are reading as follows.
Baro sensor ( by the air filter) constantly 30 Kpa Basically the atmosphere pressure at the top of Mount Everest
Boost sensor (by the throttle body) 100 Kpa Fluctuates slightly the throttle position

Would I be right in saying they should be the same at ignition ON?
I’ve got 5v supply and good ground to both I’ve also measured the reference voltage at the ecu plug end they are also the same, and have had the same results from three MB supplied sensors

Obviously it’s stuck in limp with EMl on
Any help or advice would be fantastic
Many thanks

 

[W1ghty]

Hi guys, new here so go easy on me plz... I’ll start with the car details. E350 Cdi auto w207 2009 showing 128000 miles.
After spending nearly a £1000 with my local main dealer on diagnostics and a new Maf New system, For them only to tell me I need a new Ecu as well Another £900, but when I asked if that would cure the fault they simply couldn’t guarantee it. The fault is a boost pressure one but exists right from ignition ON before you even start the engine. The two pressure sensors are reading as follows.
Baro sensor ( by the air filter) constantly 30 Kpa Basically the atmosphere pressure at the top of Mount Everest
Boost sensor (by the throttle body) 100 Kpa Fluctuates slightly the throttle position

Would I be right in saying they should be the same at ignition ON?
I’ve got 5v supply and good ground to both I’ve also measured the reference voltage at the ecu plug end they are also the same, and have had the same results from three MB supplied sensors

Obviously it’s stuck in limp with EMl on
Any help or advice would be fantastic
Many thanks

I would start by saving yourself some serious money and leaving the Main Dealer network , where do you live so someone can recommend an MB independent that works at half the hourly rate and more importantly knows older cars

 

[10seventy1]

Thanks, I don’t mind spending the money with a main dealer or an indie, the problem is not being guaranteed that the next £1000 pound spent will fix it. So hopefully someone might share similar Symptoms and how it was resolved.

 

[amazighman]

Thanks, I don’t mind spending the money with a main dealer or an indie, the problem is not being guaranteed that the next £1000 pound spent will fix it. So hopefully someone might share similar Symptoms and how it was resolved.

Personally I wouldn't pay anything for MB dealers to guess and Change parts as they go if the problem still persists then they have to sort it then get paid .
Like said above I d go to an independent garage , some of them do try parts to troubleshoot the problem .

 

[Chrishazle]

Put you approximate location (somewhat closer than your current "UK") into your profile, and someone on here will be able to recommend a local indie that will give you better and cheaper service than your main dealer who only knows how to guess and change parts (at your cost) in the hope it will cure the fault - and when it does not, will suggest changing another part - and another, and another!

Sounds like you need an indie with star, knowing how to use it, and having knowledge of 11 year old cars - in other words having grey hairs rather than some sort of shaved monstrosity!

 

[markjay]

I work in IT, and in my trade, whenever someone isn't sure about what is causing the problem, they always blame 'the firewall'. This is because for most people the firewall is a black box, but as someone who used to configure them for a living I can tell you that there's nothing mystical nor mythical about how firewalls work, it's just a piece of kit that is no more likely to be the cause of the problem than any other piece if kit on the network.

From what I see, the equivalent of 'the firewall' in the car maintenence business is 'the ECU'.

 

[Tonygw]

I know none of the replies have really help resolved the issue for you, but it is definately the case that a main dealer wont help on cars of this age, not really classed as old in my eyes but they just are not that interested in fixing them.

If you live anywhere near Loughborugh I can recommend a good specialist who will spend the time to resolve the issue without costing £1000!