737NG lower DU oil press and oil temp show red bar on the ground

[jjleo]

http://www.pprune.org/attachment.php?attachmentid=1128&stc=1&d=1477230188
as the pic shows.
can anyone tell why it happens on the ground?
thanks

[ImbracableCrunk]

I think you need to link the picture.

[Tom!]

Its caused by missing engine limits from the EEC.
A red bar on the oil temperature vertical scale/bar indicates that the recording in the DEU non-volatile memory of the downloaded engine limits data are missing or have been erased.
Fixed on the ground by putting the start switch to CONT for 10 seconds. The EEC will re download their info to the DEUs then.

I have seen it only once in 6 years on the NG