: Greatings from Denver!

XLR 06
09-02-10, 11:33 AM
I just wanted to say hello. I am the new owner of a 2006 black XLR with lots of electrical problems....lol. Gee where you guys heard that before? Despite the issues, I think the XLR is uniques and truly amazing.

I have two immediate issues. First, my top won't lower at all at the moment. Is there a prevalent gremlin I should inspect? I am going to solve the top problem, as I don't want to be tied to a dealer. Second, the only way to start my car at to moment is to trip the soloniod in the fuse panel after pressing the button in the interior. It is running in limp mode I think due to the coolent sensor. Yes, it has coolent. Any cogent advice from any one is welcome.

As an aside, I am going to post another thread on swapping the Northstar for an LS7. I know the idea has been tossed about a bit. I have looked at it for about six months before completing my purchase. this can be done fairly economically. Your thoughts?

09-03-10, 03:53 AM
1) At what point in the retract sequence is the folding top failing? --This is important as it can help isolate the problem to a specific switch or sensor. Does the rear decklid operate correctly?

2) As for the starting issue, which "solenoid" are you referring to and which fuse panel? The XLR has a UBEC under the hood and an integrated BCM with fuses and relays under the passenger side toe panel.

3) Do you have a shop manual? If not, you might want to read up before considering a new engine . . .

4) A Tech 2 (yeah, at your dealer) can isolate both of these problems in a couple of minutes. --They can cost about the same as an extended warranty if you're handy with tools and a parts list.



XLR 06
09-04-10, 10:00 AM

I can't thank you enough! The top won't initiate the sequence at all. It went from functioning to doing nothing in one fail swoop.

The solenoid I'm referring to is in the UBEC under the hood. Can I get a shop manual at GM? I take it Tech 2 is a scan performed at the dealer? Sorry to be so dense but I'm just starting the learning curve with this particular car.

09-04-10, 01:36 PM
No need to thank me, I haven't done anything yet. . .

1) Again, does your rear decklid (trunk) raise? If the system instantly failed, start checking fuses first. Does the pump start? Are the valet and cargo barrier switches configured properly?

2) A Tech 2 is a sophisticated scan tool programmed with the XLR's diagnostics, used by the dealer to troubleshoot and update parameters in GM vehicles. For instance, if you install a new radio, your VIN needs to be programmed into the replaced part. The Tech 2 is bi-directional, meaning it can communicate with the vehicle and issue commands, --like cycling the positions of any one of the five solenoids in the folding top hydraulic manifold. Aftermarket scan tools can only read, and with the XLR, are very limited. The Tech 2 can tell if you press a door switch to verify the system sees the request. One of the first checks it could make on your folding top issue is whether or not the control switch retract command is being activated and seen by the bus. This can also be done with a multi-meter, but the Tech 2 is much faster without having to get at the back of the switch. Expect to pay between $2-4k for one. I got a GM Tech 2 (not a Chinese knock-off) from eBay for $2k, complete with CANdi module (needed to comm w/the GMLAN bus) and use it on both my cars. I look forward to my next top malfunction now. . . It cost as much as an extended warranty, but it will last longer, and can be sold later on as well.

The XLR uses GM's new(er) GMLAN high-speed bus to communicate with modules that require split-second action for safety, like the electronic braking system or distance sensing cruise control. I know of no other scan tools that can communicate with this bus. It also uses the older OBD 2 bus, as well. XLR was one of the first vehicles to integrate the two buses. The BCM is the gateway between the two.

3) Shop manuals are available from Helm Inc. Or eBay.

4) We may have a verbiage issue between relays and solenoids. They are quite different. There are no solenoids in the UBEC, only relays. There are two solenoids in the BCM. What are you manipulating to get your car to start?

5) As for the engine swap . . . I have no doubt a different engine could be installed, but the system is set up so the other (safety) functions like stabilitrac, cruise control, anti-lock brakes, engine drag control, and traction control all communicate with the engine parameters. Can a tuner guarantee these will work as reliably with a different engine? What about the PAL algorithm in the TCM? The XLR is much more than an engine. For that reason alone, I'd pass and buy and mod a V model if HP is your goal. A dealership might be leery about working on a Franken-XLR. And as previously posted, financially, it's a financial black hole. Cool? Sort of. However, it's your money. . .

-- You stated you didn't want to be tied to a dealer. Few of us do, but . . .

Unless you're very car-savy and equipped with the right tools, consider yourself in voluntary bondage. But comfortable bondage, wrapped in nice leather and millisecond responding restraints that don't try to dominate you.

The XLR is too complex (engine notwithstanding) to let anyone other than a certified tech even touch one; otherwise you're taking your chances and paying someone to learn-as-they-go with yours. With the right tools and training, a certified GM XLR tech will fix it right and quickly. Since your car is new (to you) it's worth it to have them run a diagnostic (about ten minutes) to identify both of your problems (A defective ignition circuit and inoperative folding top are pretty major quality of XLR life issues) and move on. We can throw ideas at you all day long on these forums, but it's just educated guesswork. The Tech 2 will find them right away.

There is no free ride with an XLR. Cheapskates need not apply. People are snapping them up now that they've depreciated, but the cheaper price of admission doesn't take away from the fact that this was GM's halo car. It's still smokin hot next to anything they're putting out even today --though there are some really sexy Cadillacs out at the moment. None have the staggering number of integrated features found in the XLR, but they're catching up. Parts prices, troubleshooting methodology and repair techniques are still off the hook. There is a price for everything. Get your car squared away, and have fun driving it!


10-23-10, 10:44 PM
This Is not the Car to start learning on, Unless you have a lot of money! Tech 2 required. And shop manual also. Or Extended Warranty! I Was A certified master tech. for Chevrolet.I used to work on Vettes all day. (retired in 03)Take my word for it ,this is a different Animal.But I'm in love with mine.

11-02-11, 07:06 PM
I will get you some info to help

11-02-11, 10:21 PM
Uhhh . . . this post is over a year old. . . .

11-03-11, 10:09 PM
I am lending a hand on the 7.0L upgrade

11-04-11, 01:48 AM
Oh. . . okay. I thought this was an electrical problem thread. My bad. I wasn't aware an LS7 engine was being considered for a Folding Top upgrade . . . Let's see some pics! (And cycle times!!)

11-04-11, 02:45 AM
I am lending a hand on the 7.0L upgrade


11-04-11, 05:51 PM
I need to pull the folding top training out and get it to Cliff also.