valet r/s dei bypass on 2001 lexus

I Have a 561r Valet remote start coupled with a DEI 555x keyless bypass on a 2001 Lexus GS430 that has worked well for over three years.

The set-up was installed by a very reputable installer who has done numerous audio, and securitysystems and specializes in foreign/european vehicles.

I recently had to come to the Northern U.S. where it is cold cold  with the military, and what do you know the remote start quit working. 

 Well it will go thru the crank sequence, and then never start.  I immediately suspected the bypasswas not producing the key cylinder transponder code.  I am having trouble reprograming the bypass because the LED never illuminates to let me know it has power, or syncing the master key becuase i get no response from the bypass module. 

 It is 555x designed for this model Lexus and all the wires and fuses appear to be connected via soldered joints.. 

Does anyone have any ideas of a starting point to trouble shoot from here?  I have ordered a new 555x module to have on hand to try if anyone thinks the one I have is defective. I do remeber this happened once before and I took it to the installer and he had it up and going within a few hours, but I am over 1,000 miles away from him now... Thanks for any suggestions..  

Greg

Will the car remote start with a working key placed in the ignition cylinder and left at the OFF position ( not turned ) ?  Any LED flashes from the 561r?  Any "security" type lights on the instrument panel?

Use a Digital Multi Meter to check that the 555x is getting +12v at the Red wire.  Verify that the Black wire is going to a solid chassis ground.  Verify that the Blue wire is still connected to the 561r Blue wire at the 4 Pin connector and that it goes to ground during a remote start.  Verify that the Green wire is going to the cars' Yellow Keysense wire at the ignition switch and that it goes to ground when a key is inserted into the ignition.

That should get you going in the right direction. 

Soldering is fun!

The car WILL crank with the key in ignition in the key cylinder with the remoter start. I have checked the wires, but will recheck and give the results on here.  Is there a simple way to test the blue wire from the 561r for negative/ground output during startup ... I do not have access to a multimeter at the moment.  Thanks for your guidance

The DMM is the best / safest way to test.  There are some +12v computer safe LED probes that will be OK for these tests, too.

If the car will remote start and run with a key in the ignition ( but not truned ), then it would appear that the 555x module is not doing anything. 

Soldering is fun!

well I took my dash off today and disconnected the bypass module, reconnected it and started the car with the remote start..  I don't know how or why, but the car cranks with the remote start now.  Maybe the bypas lost it's programming and it regained the signal when the car cranked....Well now I have an extra 555x module as a back-up I guess since I ordered another thinking the module was bad..Thanks for the help from the forum tough!