2005 Cadillac CTS 3.6L V6 VVT

Cadillac CTS

2005 Cadillac CTS

Purchased vehicle new, from dealership. Car has always been reliable, except for a fuse-blowing problem, in which the car wouldn’t start, back in 2007. That was the 10a fuse, listed as (HTR VLV/ CLTCH), which is part of the ‘Jumper to Start Relay Coil for Automatic Transmission’. After blowing 3 or 4 additional fuses, I replaced it with a 15a circuit-breaker fuse, and have had no problems since.
The same thing is now happening again, with the car not starting. Note: Battery is fully charged, and all lights and accessories are working. I thought my current problem may have been with the same fuse, so I put in a new one, and still nothing. I then tried putting in a new Starter Relay, and that did nothing.

When I put the key in the ignition, turn to accessory, everything lights as normal, continue to start, I get nothing. Now I can’t turn the key all the way back to remove it, so it stays in the access. position. I have to push the release pin under the column to get the key out. I have now discovered that if I use a test-light, from the neg. side of the battery to one of the pins of the starter relay, I can start the car. This was done with both the old & new relay. The car will stay running.

When I shut the car off, I can now start it with the key, numerous times. If I return to start it in 15 or 20 min., it starts fine with the key. After a half hour or so, it will no longer start with the key, and I have to jump it with the test-light again. So, where I am at now, is I can jump it, go anywhere, and do anything, as long as the car is only turned off for 15min. or less, in order to start it with the key. It seems that by jump-starting, it energizes something for a short period only. But strangely enough, it started yesterday, after an hour of sitting, then 3 hours later, it didn’t. Everything that I have done so far, is from the advice of a long-time friend, and auto mechanic, who specialized in electrical problems, but does not know everything about many newer cars, as he is now retired.

I am now at a ‘stand-still’, with no other options, and need an experts advice. Thank you.

3 thoughts on “2005 Cadillac CTS 3.6L V6 VVT”

  1. Sounds like you and your friend have isolated the problem down a bit, that leaves you with only a few things that it could be.

    Check for battery voltage on both sides of the HTR VLV/ CLUTCH fuse(with key in “ON” position). If you do not, check and replace the IGN 1 Relay. If you do then you will need to check the clutch pedal switch. If it is an automatic, and the IGN 1 relay and the fuse check out, you will need to check the wiring from the fuse to the starter relay. I have provided a free wiring diagram below to help assist you in your testing.

    2005 Cadillac CTS 3.6L Starting System Wiring Diagram

    How to use a multi-meter

  2. I have had the same problem bro with a cts it took me about 3 days of testing and troubleshooting but the problem is the P.C.M I can guarantee That. You will have to order the pcm from the dealer give them ur vin# and they will get u the correct pcm never try to put a used pcm, it’s ok in some cases but with this one can’t go wrong with new. Then u will have to have the dealership program the pcm to the vehicle. I know it sounds crazy but what’s actually happening is the pcm memory stays on for so long, after a certain amount of time it goes into a sleep mode then when u turn the key on it basically activates the pcm which controls the injectors coils and so on. When u start the car manually by having the key on and hitting the starter relay it basically wakes the pcm and it works fine.

  3. With the exception that sometimes the transmission does not shift correctly. If that happens stop, shut down and restart

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