Newbe to form -

I have installed a Metra AIP-TY02_ID Ipod adapter to the CD changer input of the OEM radio in the Tacoma - works ok - but input levels are low - so i want to add a preamp inline to raise the gain of the adapters output to the radio's cd changer input - However I cannot find any info about the radio
I believe that it is a Pioneer - does any one know a link to a site that has the information of either the Metra's TY02 or the Pioneer Cd changer pinouts