My 2000 Powerstroke diesel has engine code P0478 "Exhaust Pressure Control Valve High Input".

What does this mean and how serious is it?

Apart from the "Service Engine Soon" light being on, the truck seems to run normally.


Thanks
Grcutter

 

Possible causes:

-- stuck EBP butterfly valve

-- restricted exhaust

-- plugged EBP sensor line

-- misadjusted EPR linkage

-- F-Series wastegate turbo may be overboosting

l Access PIDs MGP and RPM.

l Road test vehicle selecting the best gear to achieve a 2500-3000 rpm acceleration.

l Note the highest boost pressure. This is best accomplished either climbing a hill or with the truck fully loaded.

l Does MGP read 18 psi for over 5 seconds?

Yes
GO to «KH5».

No
GO to «DE18».

 

Thanks for the possible causes. Your 3rd one was right on.

It turned out to be a plug sensor tube (p/n 1C3Z-9D477-AA) and
a plugged sensor (p/n 3C3Z-9J460-AA).

Sincerely,

Grcutter