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Discussion Starter · #1 ·
My 159 (07 1.9 JTDM) has started to randomly go into limp mode for a short period of time and then snaps out of it. Not good when you're in traffic! Any pointers please?
 

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We did, nothing showing :-(
Cleaned the EGR valve as a matter of course

Could be injectors or a cam/crank sensor but that would usually throw a code.

I would reckon that limp mode would always throw a code, since the ECU chooses to go to limp mode (usually because a sensor provides no or improbable information).

Is the engine in limp mode or is it just running poorly?
Could be DPF regen, I've read on here some have poor idle when running regen.
I believe you can activate regen manually using MES, not sure though.
 

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Discussion Starter · #6 ·
Don't know what scanner he used but he uses it for his business. (Not sure that helps)
I would say limp mode, it'll run at a steady (slow) speed, then will pick up again & be back to normal.

There used to be a post on here about this kind of thing, or other poor running symptoms, cant find it now though.
 

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I would say to get it checked to someone who knows these cars because you may have bitter news if you don't.

Like said here:
- vacuum pipes
- dpf clogged and may not even throw and error because sensors on the dpf may be working bad, and you may have a clogged dpf that just cant regenerate and may damage turbo and no errors
- air pipes damaged getting to bad fuel mixture
- fuel filter, never start with injectors when what's before it is not working properly
- intake manifold clogged or throttle body dirty

Hope this gives some clues but best is not to take the risk.

Enviado do meu MI 6 através do Tapatalk
 

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Discussion Starter · #8 ·
I would say to get it checked to someone who knows these cars because you may have bitter news if you don't.

Like said here:
- vacuum pipes
- dpf clogged and may not even throw and error because sensors on the dpf may be working bad, and you may have a clogged dpf that just cant regenerate and may damage turbo and no errors
- air pipes damaged getting to bad fuel mixture
- fuel filter, never start with injectors when what's before it is not working properly
- intake manifold clogged or throttle body dirty

Hope this gives some clues but best is not to take the risk.

Enviado do meu MI 6 através do Tapatalk
Right, thanks :depressed:
 

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Dave, is your car Q4? I had similar on a Q4 which turned out to be a short in the oxygen sensor wire. It rubbed against the shaft under the heat shield and peeled off the insulation causing a short. It burned fuse 21 (I think it was 21) and it was very intermittent. As the car drives the wire would bounce and touch the shaft causing a short and limp. But sometimes you drive and it doesn't touch and no limp mode.

So check all rotating parts under the car and see any wire is touching. If it is not Q4, check drips, perhaps something is dripping on a wire and causing an intermittent short.
 

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Discussion Starter · #11 ·
I would say to get it checked to someone who knows these cars because you may have bitter news if you don't.

Like said here:
- vacuum pipes
- dpf clogged and may not even throw and error because sensors on the dpf may be working bad, and you may have a clogged dpf that just cant regenerate and may damage turbo and no errors
- air pipes damaged getting to bad fuel mixture
- fuel filter, never start with injectors when what's before it is not working properly
- intake manifold clogged or throttle body dirty

Hope this gives some clues but best is not to take the risk.

Enviado do meu MI 6 através do Tapatalk
I've just taken it for MOT, the guy there said he could hear air either escaping or being sucked in, which is what you're pointing to. Still seems odd though because apart from the odd bout of low power, it runs fine.
 

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Discussion Starter · #12 ·
Dave, is your car Q4? I had similar on a Q4 which turned out to be a short in the oxygen sensor wire. It rubbed against the shaft under the heat shield and peeled off the insulation causing a short. It burned fuse 21 (I think it was 21) and it was very intermittent. As the car drives the wire would bounce and touch the shaft causing a short and limp. But sometimes you drive and it doesn't touch and no limp mode.

So check all rotating parts under the car and see any wire is touching. If it is not Q4, check drips, perhaps something is dripping on a wire and causing an intermittent short.
Not Q4, plain old 1.9jtdm. Mine does have the same effect, intermittent but when ok runs fine.
 
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