Distinct Count

Tried several suggestions in the forum but haven't found one to match my needs.

I have one table, Jupiter and need to use this query

SELECT Jupiter.codename AS Build, Count(Jupiter.tooling_ind) AS [# Needing Tool], Count(IIf([tool_req_type]='OR',([requisition_no]))) AS [# Tooled], [# Tooled]/[# Needing Tool] AS [% Tooled], Jupiter.tooling_ind
FROM Jupiter
GROUP BY Jupiter.codename, Jupiter.tooling_ind
HAVING (((Jupiter.tooling_ind)="Y"));

For each "codename", there is an attached "part_no" which can appear under a codename several times. The problem is that I need to count only one instance of the "part_no" for each "codename".
So, my query looks like this:
Build # Needing Tool #Tooled
LP1 769 192

The # Needing Tool is counting every record that, say pn 10592 shows up in and I need it to be counted only once in each "Build"

I did try this suggestion I found with no results.

SELECT Jupiter.codename AS Build, Count(Jupiter.tooling_ind) AS [# Needing Tool], Count(IIf([tool_req_type]='OR',([requisition_no]))) AS [# Tooled], [# Tooled]/[# Needing Tool] AS [% Tooled], Jupiter.tooling_ind
FROM (SELECT DISTINCT Jupiter.part_no FROM Jupiter)Jupiter
GROUP BY Jupiter.codename, Jupiter.tooling_ind
HAVING (((Jupiter.tooling_ind)="Y"));

Is there a way to do this somehow?

Thanks!

Toni