Thread: which P38 ?

On second thoughts, the fuel mapping/timing etc. is controlled by the EMS. So switching the BECM to "Police" setting would imply an instruction to the EMS from the BECM... If ...and it's a big "IF" this is the case then the "instruction" could be either to specify the new settings...or simply direct the EMS to adopt "setting Police" which is already part of the EMS firmware.

I am thinking that it is likely to be the latter situation...if at all. The original post prompted me to do a bit of a search... the Police Setting appears to be mainly associated with various lighting options as well as the vehicle requiring additional wiring looms to be added to the existing harness... There is a specific warning in the BBS against setting the BECM to Police if the vehicle has not been set up....

EDIT: the extra advance may have been due to the EMS detecting a lean mixture and compensating thereby causing the oxygen sensor to read "rich". Need to have a look at the fuel trim as well to get some context.

There is only one 'real' way to find out!