Rusty Posted October 18, 2008 Report Share Posted October 18, 2008 I need the combined wisdom of the team for this one. 2001 STS . Recurring pattern: turn the key, no sound, nothing. Lights work O.K. After waiting anywhere from 15 minutes to an hour or more it starts and runs fine. No codes. Caddy dealer says if it happens while they can observe it they can diagnose the problem. It happens again. I have the car towed to the dealer, they keep it all day - and of course it starts fine - every time. No codes , and supposedly the scan tool didn't provide any clues. The Delco battery is 3 years old but checked O.K. (according to the mechanic.) Dealer suggests the probable cause is a faulty ignition switch - $300. Not being in the mood for diagnosing the problem by the parts replacement method, I decline and drive away. When the problem manifests itself again in a couple weeks, I had found my spare key, and voila, it started right up. I’m feeling good. But then the no start pattern appears again a couple of more times – each time starting fine after it sits for a few minutes. I’m thinking that maybe the security pill inside the key might be breaking down. I buy a new key, and for a couple weeks all is well. But the no start problem sporadically reoccurs. I take the car to the Caddy dealer…. This time while they have it the no start condition does occur. Now I’m thinking, this will finally yield an answer. Dealer suggests again that it is the ignition switch, and I open my wallet and remove $300, consoling myself that that at least this will put an end to my misery. Wrong again. I drive it home - and a few hours later - no start / no crank . This one has really been a test. Any help or comments from the esteemed membership would be greatly appreciated. Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted October 18, 2008 Report Share Posted October 18, 2008 My guess: PRNDL switch fault. The safety interlock that ensures the car can't start unless in park or neutral is malfunctioning. When this happens, put your foot on the brake and run the gear shift through the gear positions and back to park then try to start again. If it starts after this procedure, ask your dealer to replace the PRNDL switch. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 18, 2008 Report Share Posted October 18, 2008 If there is a problem with the ignition switch or the key resistor contacts you will get codes. No codes means that it is more likely the PRNDL switch (there are two of them) or a brake switch (there are two of these, too, and one of them just "talks" to the PCM). -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
JimD Posted October 18, 2008 Report Share Posted October 18, 2008 The start control circuit is not complicated. In addition to the various switches, there are two relays in the underhood fuse box where corrosion could be a problem. http://i70.photobucket.com/albums/i101/Jim...tartcontrol.jpg Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BuenoOffenhauser Posted October 18, 2008 Report Share Posted October 18, 2008 Consider the starter solenoid as a possibility. Link to comment Share on other sites More sharing options...
Ranger Posted October 18, 2008 Report Share Posted October 18, 2008 If there is a problem with the ignition switch or the key resistor contacts you will get codes. No codes means that it is more likely the PRNDL switch (there are two of them) or a brake switch (there are two of these, too, and one of them just "talks" to the PCM). Two PRNDL switches? Link to comment Share on other sites More sharing options...
Rusty Posted October 18, 2008 Author Report Share Posted October 18, 2008 Thanks for the tips. I'll be in a better position when I approach the dealer for the correct fix- and will report on the outcome. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 18, 2008 Report Share Posted October 18, 2008 If there is a problem with the ignition switch or the key resistor contacts you will get codes. No codes means that it is more likely the PRNDL switch (there are two of them) or a brake switch (there are two of these, too, and one of them just "talks" to the PCM). Two PRNDL switches? Ranger -- I believe that there is a PRNDL12 switch and a PRND switch. One goes to the PCM and the other has the lockouts to starting the car, I believe. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Ranger Posted October 19, 2008 Report Share Posted October 19, 2008 I'd have to check the manual, but I have always believed there is only one (mounted on the trans) and it does both jobs. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted October 22, 2008 Report Share Posted October 22, 2008 You're probably right, because I got my opinion from posts here, not the manual, and I probably just misunderstood the posts. I can understand two brake switches but the PRNDL switch only talks to the PCM and it makes sense that both engine and transmission control are handled by that signal, and both engine and transmission control are in the PCM. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Ranger Posted October 22, 2008 Report Share Posted October 22, 2008 There definitely are two brake switches. Link to comment Share on other sites More sharing options...
Rusty Posted October 23, 2008 Author Report Share Posted October 23, 2008 The PRNDL switch checked out O.K. and power was available up to the starter. So, a decision was made by the tech to try replacing the starter. ( $268 parts + $ 255 labor) I haven't had a no start event since, and hope that finally corrected the problem. Time will tell. This has been an expensive trial. Next effort will be to recover the cost of the unnecessary ignition switch replacement. Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted October 23, 2008 Report Share Posted October 23, 2008 I hope it stays fixed. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
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