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Intermittent Starting

newv

Seasoned Member
Joined
Jul 16, 2014
Messages
47
Location
NM
Need some help with my 2006 XLR-V not starting.

Did a search through the forums but didn't see as many folks with this issue as I thought. Here's the background;

XLR wouldn't start, had power to accessories, brake pedal moved softly toward floor as normal, shift lever felt normal, heard multiple relay clicks but not starter solenoid (I think) and no crank. Get out, back in, try again, this time brake pedal is stiff - doesn't move toward floor, and shift lever button feels stiff - like it wouldn't shift. Hit start, no relay clicking (or less relay clicking) no crank.

I removed the battery cables from the battery, cleaned the ends and reattached - car started right up, I drove it home. Figured that's a sign of a weak battery, so replaced the battery - car would not start with new battery (same routine as above). Replaced the fob battery - no change. Let the car sit a few days, went out, detached and reattached the battery cables - car started right up. Drove it around for a couple days with multiple starts - no problem.

Leaving work tonight - won't start. Same thing as the first time, power to all accessories, doors, etc. Soft brake pedal and shift button, multiple relay clicks - no crank. On next attempt pedal and shifter are stiff, no relay clicks. Tried jumping - no help.

Absolutely terrifying to think of having to remove the supercharger to get at the end of the positive cable and the starter if either is bad!

But two things did pop up in the forums here -- a bad brake pedal sensor and a bad park position cable grommet at the transmission. Anyone had starting problems that traced to one of those things? Any good way to tell? Are these reasonable DIY (I can do a lot but an no mechanic). Poor car is sitting in the parking lot at work and I hate to tow it to the dealer and have them tackle the supercharger removal first if it is really one of these simpler fixes.

This all brings up the answer to a question you'll ask and a follow-up question from me. I do not have a Tech II so I haven't checked codes. Where can I buy a Tech II and are the Chinese clones good enough or do I need to hunt down an original Hewlett-Packard made version?

Appreciate any and all help/ideas.
Thanks
 
Buying a Tech 2 has been written about extensively on this site. I wouldn't spend that kind of money (you'll need a set of service manuals as well, and they're not cheap) for this problem.

Did you have the battery load-tested before replacement? If not, that would have saved you some $$$.

Had the same symptoms you describe. The transmission shift interlock solenoid wasn't engaging under the shift lever plate. Moving the pawl manually fixed it. Written up here somewhere.

CC
 
Buying a Tech 2 has been written about extensively on this site. I wouldn't spend that kind of money (you'll need a set of service manuals as well, and they're not cheap) for this problem.

Did you have the battery load-tested before replacement? If not, that would have saved you some $$$.

Had the same symptoms you describe. The transmission shift interlock solenoid wasn't engaging under the shift lever plate. Moving the pawl manually fixed it. Written up here somewhere.

CC

Thanks. I went down the thread of shifter cable last on the site and found a great write up on it, hadn't found a lot on the shifter pawl yet. Sounds like your solenoid just quit working and it wasn't a mechanical binding issue?

I considered testing the battery, but it was old enough and so many folks on the site described problems with weak but not dead batteries that I just replaced it. I have got the service manuals already, and want a Tech II in general anyway for future issues.
 
Thanks. I went down the thread of shifter cable last on the site and found a great write up on it, hadn't found a lot on the shifter pawl yet. Sounds like your solenoid just quit working and it wasn't a mechanical binding issue?

I considered testing the battery, but it was old enough and so many folks on the site described problems with weak but not dead batteries that I just replaced it. I have got the service manuals already, and want a Tech II in general anyway for future issues.

You should get a warning in the DIS if the shifter is in the wrong gear or the brake pedal isn't pressed. As you don't mention that, I would look elsewhere. It is possible for a new battery to be defective, it happens. Analysing symptoms at a distance is unreliable, but the firmer brake pedal could be simply that you have exhausted the vacuum reservoir. Try another vehicle, pump the brakes a few times before crank, do you get a similar brake pedal feel?
 
You should get a warning in the DIS if the shifter is in the wrong gear or the brake pedal isn't pressed. As you don't mention that, I would look elsewhere. It is possible for a new battery to be defective, it happens. Analysing symptoms at a distance is unreliable, but the firmer brake pedal could be simply that you have exhausted the vacuum reservoir. Try another vehicle, pump the brakes a few times before crank, do you get a similar brake pedal feel?

Hey, I appreciate the analysis from any distance. Definitely thought about the defective battery (hoping for that unusual but happy answer), but I'm pretty sure it's not the battery now. Here's what happened next : (By the way great call on the brake pedal stiffness, that was a total red herring - I just tried it in another car and, as you predicted, same exact feel after a couple pumps. Funny I have never noticed that previously in my driving life - does it act differently in a standard trans vehicle?) When I went to try starting it this time I jiggled the shifter and kept pumping the brake pedal as I hit the start button multiple times. I had not gotten any messages on the DIC but at one point during my jiggling, pumping and hitting start, the DIC suddenly popped up and said "press brake to start" and when I did it fired right up WITHOUT me touching the start button. I know, I don't really believe it either but when I pressed the brake the car started, like it had a start command buffered in memory even though I was no longer pressing start.

That last point aside, since the DIC gave me the brake message, it makes me think it was the shifter that was being flaky, once I jiggled that into compliance then I just happened to not be on the brake at that moment and hence the message. So I believe I need to troubleshoot the shifter and the brake pedal sensor and see if I can duplicate the failure and separate the cause. Since the car started I was able to get it home, started it a few more times with no problem, then looked at the brake pedal sensor - it wasn't mechanically broken or misaligned, and I checked the transmission cable attachment a the tranny and it was fine. This weekend I'll pop the shifter cover inside and see if I can see any issues with the pawl mentioned previously. Interesting I never saw a DIC message saying the car wasn't in park, not sure what to make of that...

The other thing you make me consider is whether, once I missed a start or two, did I not push down far enough on the now stiff brake pedal to register? More correctly it was my wife doing most of the starting attempts, so at risk to home harmony I could chalk it up to her not pushing that brake down far enough. When I finally got it going I was thinking about this and was being very heavy footed.
 
Hey, I appreciate the analysis from any distance. Definitely thought about the defective battery (hoping for that unusual but happy answer), but I'm pretty sure it's not the battery now. Here's what happened next : (By the way great call on the brake pedal stiffness, that was a total red herring - I just tried it in another car and, as you predicted, same exact feel after a couple pumps. Funny I have never noticed that previously in my driving life - does it act differently in a standard trans vehicle?) When I went to try starting it this time I jiggled the shifter and kept pumping the brake pedal as I hit the start button multiple times. I had not gotten any messages on the DIC but at one point during my jiggling, pumping and hitting start, the DIC suddenly popped up and said "press brake to start" and when I did it fired right up WITHOUT me touching the start button. I know, I don't really believe it either but when I pressed the brake the car started, like it had a start command buffered in memory even though I was no longer pressing start.

That last point aside, since the DIC gave me the brake message, it makes me think it was the shifter that was being flaky, once I jiggled that into compliance then I just happened to not be on the brake at that moment and hence the message. So I believe I need to troubleshoot the shifter and the brake pedal sensor and see if I can duplicate the failure and separate the cause. Since the car started I was able to get it home, started it a few more times with no problem, then looked at the brake pedal sensor - it wasn't mechanically broken or misaligned, and I checked the transmission cable attachment a the tranny and it was fine. This weekend I'll pop the shifter cover inside and see if I can see any issues with the pawl mentioned previously. Interesting I never saw a DIC message saying the car wasn't in park, not sure what to make of that...

The other thing you make me consider is whether, once I missed a start or two, did I not push down far enough on the now stiff brake pedal to register? More correctly it was my wife doing most of the starting attempts, so at risk to home harmony I could chalk it up to her not pushing that brake down far enough. When I finally got it going I was thinking about this and was being very heavy footed.


No, you have a fault in the dash start switch if that can happen. I have an idea there is a thread here on that fault, and/or is there a recall on it? This could be your problem.

BTW, the brake vacuum reservoir is pretty standard across all domestic vehicles. A standard test of brake vacuum is to exhaust the vacuum (by pumping the pedal) before you start the engine, press firmly on the brake pedal (hard isn't required) and start the engine. The pedal should drop slightly.
 
Last edited:
You're timing is great - I just spent the morning with it and the start switch is behaving very strange.

Car wont start under normal proceedure
Now with foot off the brake:
Touch the off/accy side of the switch and get DIC message - "accessory mode on"
Touch off/accy second time and get a DIC message saying "press brake to start"
Press the brake WITHOUT TOUCHING THE ON/OFF SWITCH and the car starts!
Press (normal touch and release) off/accy and the engine starts to power down, but immediately powers back up, DIC goes through it's start up sequence.
Can not turn car off with repeated touches off/accy!
Pressing and HOLDING off/accy will turn engine off.

At no point will pressing start, start the car, I have to press off/accy twice then apply the brake to start the car, then HOLD off/accy to shut it down.

I've gotta search for that old thread...

Besides the switch flat out failing what else? It acts like a bad ground. Could it be a bad BCM? Only thing different about the weekend this all started was I washed the car as normal the day before. Perhaps I have a rusty ground connection?
 
Latest info:
Had the codes pulled at Pep Boys - they said there were none.
Can repeatably start/stop car as described in the previous post.
Took the car for a drive - all appears normal.
Since this could be the BCM going bad I did not operate the top, but the trunk opens just fine.
I looked for bad ground straps - they are hard to see but saw both large braided ones from underside rear engine - looks fine.
I looked at the connections and BCM under the passenger kick panel - looks fine, no moisture or obvious abrasion - but boy are those wiring harnesses are jammed in - could easily envision a wire getting pinched or rubbed bare - but no evidence of this.

Has anyone ever had the switch go bad? Any other ideas? Hate to turn this over to the dealer.

BTW, xlrlist01 - thanks for the info on brake reservoir.
 
Forgot to add - I let the car sit for couple days with battery disconnected to drain any stored charge in the circuitry and get all computers to boot fresh. Battery is operating strong.
 
Update: Resolved
Thanks xlrlist01, you were right, it was the dash switch gone bad. Replaced it a couple weeks back and have been driving it around with no problem ever since.
 
Update: Resolved
Thanks xlrlist01, you were right, it was the dash switch gone bad. Replaced it a couple weeks back and have been driving it around with no problem ever since.

Glad it is fixed.
 
Exact Problem; Now solved!

I had the exact same experience, with my '06 Base. The "Press Brake to Start" came up after switching to ACC mode and back. I tried it (without even pressing the Start button), and it worked! Got me home.

After the obligatory battery charge step (same result) I ended up taking it to Red Noland, in Colorado Springs. Marvin, the XLR tech, found it to be a "Brake pedal calibration" problem. A "relearn" of the brake pedal fixed it right up. Been working fine for a month.

FYI

Tim
You're timing is great - I just spent the morning with it and the start switch is behaving very strange.

Car wont start under normal proceedure
Now with foot off the brake:
Touch the off/accy side of the switch and get DIC message - "accessory mode on"
Touch off/accy second time and get a DIC message saying "press brake to start"
Press the brake WITHOUT TOUCHING THE ON/OFF SWITCH and the car starts!
Press (normal touch and release) off/accy and the engine starts to power down, but immediately powers back up, DIC goes through it's start up sequence.
Can not turn car off with repeated touches off/accy!
Pressing and HOLDING off/accy will turn engine off.

At no point will pressing start, start the car, I have to press off/accy twice then apply the brake to start the car, then HOLD off/accy to shut it down.

I've gotta search for that old thread...

Besides the switch flat out failing what else? It acts like a bad ground. Could it be a bad BCM? Only thing different about the weekend this all started was I washed the car as normal the day before. Perhaps I have a rusty ground connection?
 
I had the exact same experience, with my '06 Base. The "Press Brake to Start" came up after switching to ACC mode and back. I tried it (without even pressing the Start button), and it worked! Got me home.

After the obligatory battery charge step (same result) I ended up taking it to Red Noland, in Colorado Springs. Marvin, the XLR tech, found it to be a "Brake pedal calibration" problem. A "relearn" of the brake pedal fixed it right up. Been working fine for a month.

FYI

Tim

Glad it has worked for a month. Should it happen again (and it might), you need to suspect two possible problems:
1/ The sensor (switch) on the brake pedal is failing, easy to replace
2/ A corrosion problem in the BCM at the harness end for the brake pedal position sensor. Several have reported this problem here over the years. It is an easyish fix once diagnosed.
 

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