P3400 Trouble code L77 6.0Litre

[MikesCapriceV]

Hi All, Maybe someone can help. I have a P3400 Fault code along with engine light on. The code says Bank 1 Cylinder Deactivation System. Car runs normal , no loss of power and fuel consumption normal. 105,000 easy ks on it. Thanks in anticipation. Michael

 

[BlackVXGTS]

Refer to the attached for info on DTC (Diagnostic Trouble Code) P3400. As you have already noticed, the fallback when the error occurs is to return from V4 mode back to V8 mode. In other words, normal V8 operation.

 

[MikesCapriceV]

Thank you very much, It will take some chewing through but i assume you are saying whilst the code is still present and not reset, it will continue to run in 8 cylinder mode under all conditions. I guess that is good as it will give me time to get it sorted. regards, Michael

 

[Skylarking]

I guess that is good as it will give me time to get it sorted. regards, Michael

The DTC means that the performance in V4 mode isn’t as expected which can indicate a mechanical issue is at play.

It could be nothing serious in which case it’s ok to drive around or it could indicate a faulty LOM (faulty deactivation solenoids) in which case it’s ok to drive or it could be dirty oil which results in the lifters (cam followers) not collapsing as expected which may or may not cause further damage. Or it could be some other mechanical issue that results in airflow through the motor not according to specs…

In my book, if it’s dirty oil which can be a cause of lifters not collapsing, such could possibly cause issues with the lifter rollers jamming which can then start to chew up cam lobes …. If that occurs, driving it may not be the greatest idea (unless you want an excuse to rebuild your engine).

So I’d not sit on it for a long time and would get your oil and this issue checked out sooner rather than later…

 

[MikesCapriceV]

Ok thank you, its not my daily driver, its only done 3000ks in 12 months and oil is clean to the eye and i'm about to change again. Correct oil is used and normally every 5000ks so that part i know is good. It did happen two years ago, i cleaned the MAF with correct cleaner , it seemed to fix but i does so little ks, its hard to know. We had a mouse plague over the last two years so ill check wiring first and manifold filter and obvious things myself and then ill get someone to check the electrical and sensor side of things if it doesn't resolve the issue. Thanks again Michael

 

[lmoengnr]

Maybe one of the DOD solenoids on cylinder 1 or 7 is playing up.

 

[MikesCapriceV]

Yes i think ill start there and manifold filter and oil pressure and look over harness. I'm thinking if i cant find anything, i might have it turned off, there must be a performance car business in town that can do that. Thank you, regards Michael