prestige aps620 issue

I  installed a Prestige APS620 in a 2009 Hyundai elantra.  Not my first install, and everything was going pretty smoothly.  I believe the Tach is available in the driver's kick, but I was unable to find it, so I set the RS to voltage.   The car starts OK, the parking lights come on, and then dies after a minute or so.   The diagnostic codes flash twice, indicating "low or no tach".  I reprogrammed the brain for voltage, i.e., reaffirmed it was properly configured, changed setting  to tach and then back again to make sure.  This worked the first time i started the car, subsequent RS activations failed as before.  The car has no transponder, and the car seems to run fine in pit stop mode.   I'm starting to suspect the brain.  

Any guidance would be helpful in locating the Tach and diagnosing the issue.

Thanks Chris.  Where do you usually grab tach on the Sonatas that you have done?   I've just finished powering down the brain and confirming I have a solid ground.  I'll reaffirm programming & try your suggestion.  I really would prefer Tach to voltage...

Thanks for the update and the info Chris.   I tried your voltage setting recommendation and it worked great!   I find the APS620 to be a great product with poor documentation...no real explaination of this voltage setting, the pit stop mode, eliminating chirps, etc., but the product is solid.

The Hyundai  service information identifies the tach wire, which goes to the tach in the dash, in the upper (black) connector (EM11, 33 Pin) in the driver's kick, white wire, pin 28--this appears to bethe wire on the side closest to the firewall and low in the connector.   I measure this to be 7.5Vac, not really varing with engine speed--not certain this is the right wire.  I'll keep looking...

Chris--Thanks for the info.  

I confirmed that the Tach IS on the black connector as I described earlier.  The Hyundai service info confirms this white wire as the same wire that goes to pin 61 of the 3.3L PCM (or pin 86 of the 2.4L PCM) as identified by the Bulldog website.  The wire also connects to pin 18 of the instrument cluster connector M08-1, the black 20 pin connector on the dash guage cluster for both models.   The Tach is in the Driver's kick, same location for both models;  the white wire in the top black connector, row closest to the firewall.  There are only 3 signals in this row--(From the top going vertically down) blue, gray, two open positions then the white.   Gray is for the sunroof power if equipped.  I connected to this wire and the RS learned the signal, then started under tach control.  It also provides over-rev protection.

Thanks for all your help.