Limp mode... Help?

[JBM1]

Hi everyone I am new here and recently bought a E350cdi 2009 coupe.
However I have had the car back to a specialist as under full revs the car suddenly goes into limp mode with no engine management light.
They were unable to find any codes or recreate the problem.

I've collected the car back and tried my best to recreate the issue without success

however this morning it happened again... appears it only goes into limp mode on initial start up and while the engine is running cold. After the car is running at temp it never happens no matter the revs or speed

does anyone have any ideas on what this could be??
Turbo is boosting at 19psi when at temp and boost without an issue.

I did find a code of P0299 (underboost) using torque pro.

thanks in advance for any help
Jon

 

[mercmancdi]

ALTHOUGH YOU ARE GETTING NO WARNING LIGHT ?
The P0299 code indicates that the Turbo or Supercharger "A" has excessively low output. The ECU looks for a specific range of boost and when the low boost is detected by the ECU, it sets a P0299 code. This code will illuminate a Check Engine Light on the dashboard and may put the vehicle in limp mode.

 

[JBM1]

ALTHOUGH YOU ARE GETTING NO WARNING LIGHT ?
The P0299 code indicates that the Turbo or Supercharger "A" has excessively low output. The ECU looks for a specific range of boost and when the low boost is detected by the ECU, it sets a P0299 code. This code will illuminate a Check Engine Light on the dashboard and may put the vehicle in limp mode.

Good evening mercmancdi,

and thank you for the response, I had seen this with a detailed explanation but was more confused as to how it is only giving low boost on cold start usually around 4th gear (auto box) 50-80mph

It mentions a lot of possible things to check but would of thought most of the major issues would constantly cause limp mode or an engine light?

I did read from an American forum possible fuelling issue of split hose but only when cold?

thanks

 

[OneForTheRoad]

Is that the v6 om642 engine. Possibles are. Exhaust back pressure sensor. Turbo actuator. Split hose ..But you really should see eml and error codes.

 

[JBM1]

Is that the v6 om642 engine. Possibles are. Exhaust back pressure sensor. Turbo actuator. Split hose ..But you really should see eml and error codes.

As far as I know yes that’s right the V6 OM624 engine.

yeah same thing the garage said was it should be flagging a Engine light or at least storing the codes.

I have today filled the tank full with premium diesel and added a system cleaner just to tick it off the list and my next check is going to be the hoses

just annoying the garage are unable to find any codes as they are an indie specialist happy to sort any faults once they find them.

 

[OneForTheRoad]

It can take 5 or 6 times before a fault triggers the eml and stores codes. Im sure youll get them soon.

 

[Peter103]

When I had a gearbox limp problem with a previous 7 g E coupe garage said bring it straight in when it next happens and leave it running, if engine off we lose fault code, I did, and they reprogrammed the gearbox software. Worked ok after, but eventually sold it on.
Good luck, welcome to the forum.

 

[Michaell]

Loose breather pipe or egr issue..i had same issue with my b200 cdi

 

[JBM1]

Good evening,

thank you everyone for your replies... think I have found the initial problem and have it booked in Wednesday morning.

looks like the previous owner was running the car with a thermostat partially open (cars struggling to stay at 80) I noticed today after running it in different conditions to fault find!

am I correct the turbo on the OM642 Is a VNT turbo?

because if my thinking is correct the build up from the thermostat issue has caused a build up on the turbo causing the underboost on a cold engine but once warm is freeing up the vanes?

if anyone could help clarify for me before I go running back to the garage

thanks again

 

[JBM1]

Just in case anyone comes across this post, i have finally had the thermostat replaced after 2 weeks of convincing them to take it off and check.

this has now been replaced but no other faults with the engine or turbo can be found to link with the P0299 EML code.

once i collect the vehicle i will update if this did resolve the problem.

 

[JBM1]

Final Update:

Collected the car last Thursday with the new thermostat working a dream. However vehicle went straight into limp mode twice while warming up.

I asked the garage if they had checked the turbo and vanes and said yes with no issues. However upon inspection they hadn't and the turbo appeared to be caked in soot. After a full tank of premium diesel and turbo cleaner the car is running spot on over the weekend with no issues after about 100 miles.

Hopefully i can actually start using the car now and enjoy it with some pictures to follow.

Thank you to everyone for suggestions.

 

[OneForTheRoad]

You need to redline it now and again to keep things clean . Try adding millers ecomax and keep away from cheap fuels.

 

[NickApp]

Is the Millers Ecomax stuff any good? I've previously used the BG244 cans with reasonable results

 

[OneForTheRoad]

Is the Millers Ecomax stuff any good? I've previously used the BG244 cans with reasonable results

It seems to quieten down the engine in the cold snap. Gives better performance and keeps things cleaner due to a cleaner burn. I used it for years but i now use . Hydra Fuel Cetane Booster 99% Pure 2 Ethylhexyl Nitrate Cetane Improver 5L 5055816636153 ebay .. more cost effective.