When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Good day all,
I am new to this site and I figure if anyone can help someone here can. I apologize in advance if this has been covered before but i didn't find a solution for my particular car. I have a 2005 c6 auto trans with a grand sport package, that I just purchased for cheap that has a starting problem but I cant figure it out. The car does not crank, everything on the interior works as it should ie. guages sweep and full power to everything. Here are the things I've checked.
New battery is at correct voltage and passed load test, alternator tested and puts out correct voltage, new nuetral safety switch and adjusted to ensure its lined up properly with park/neutral, all fuses and relays are working correctly and in the correct spot, starter works great. I took off the top of relay 43 (crank relay) and with the ignition in the on position and pushing the relay by hand the car starts perfectly fine. I'm getting 12v battery to 1 pin ignition power on another, Ground on another and nothing on the last pin even when the start is pushed. Also I have no communication with my ecm. My reader gets power but no coms link. Has anyone had this type of problem before? Does anyone have a schematic for the starting circuit so I can trace the wires and see whats going on? Does the start signal (activation to relay 43) go through the ecm? Any help would be greatly appreciated.
Thank you all for the warm welcome. I hope I can get this vette back on the road with your help. The last guy didn't take care of it. I'm new to corvette but have fixed pretty much every other kind of car out there. It took me a while to find out that the grand sport is an aftermarket package that was installed. Hopefully soon it will be cleaned up and running great!
That's interesting. Most of the conversions I saw looked like Z06 fenders. But, yes, the factory Grand Sport didn't exist in 2005.
It sounds like you're pretty handy around cars, so it might be in your best interest to pick up a set of the Y-Car shop manuals. I have them for my 2010 and also had the 2008 set when I had my Z06. There's a set on eBay for 2005, but the condition is poor and they're asking too much for them, but hopefully another set pops up.
That's interesting. Most of the conversions I saw looked like Z06 fenders. But, yes, the factory Grand Sport didn't exist in 2005.
It sounds like you're pretty handy around cars, so it might be in your best interest to pick up a set of the Y-Car shop manuals. I have them for my 2010 and also had the 2008 set when I had my Z06. There's a set on eBay for 2005, but the condition is poor and they're asking too much for them, but hopefully another set pops up.
Do you know the history? Was it ever flooded?
Thanks for the reply! Yeah it took some digging about the 05 grand sport and where it came from.
I am very handy and can do pretty much everything I need to but without a schematic I don't know what provides power or ground to different places. I was hoping there was someone that would be able to send them to me without me spending $400 on manuals. I've narrowed it down to the ECU not providing ground to activate the relay and im not sure if that is linked to the no communication to the obd port. Its going to be a long process if I cant get the manuals but oh well.
As far as the history. I don't know if it's ever been in a flood or wrecked. I'm not able to research vin numbers and the person I got it from wasn't sure either. All I know is what he told me. He said that one day it just wouldn't start and then he had a mechanic buddy replace the neutral safety switch and then it ran for afew more weeks and then i/ wouldn't start again. Then he put a new starter, alternator, battery, another neutral safety switch, transmission valve body (lol) and a new guage cluster. So basically he was just throwing parts at it. It then sat for almost 2 years. I think it may be an ecu ground issue. But im not sure which pin provides that without a schematic. I believe it also provides ground for the obd2 port. I'll keep the thread updated as I figure stuff out and thank you so much for your input. I'll definitely keep an eye out for the Y-car shop manuals. Thanks again!
Walk in the part, and if you can fire the relay to start the car, then problem is that the BCM is not sending the final start command to fire the relay in the first place.
So conditions for the BCM to send the start command to fire the relay once you push the start button,
RCDLR seeing the fob in the car, and if RCDLR does not see the fob, you will get fob not found in the DIC
Shifter assembly showing the lever in park.
Hence shifter has front contact switches that tells the BCM that the BCM is in park when the lever is all the way forward. To see if the lever contact switch needs to be adjusted, then just push the lever hard forward when you try to start the car, and if this starts the car, then will need to adjust the micro switch lever.
The second one is that you have to have your foot on the brake pedal pushing it down.
Tech II will make short work of this, since you can go into BCM data to make sure that the brake pedal sensor is working correctly, if not, then do a BPS relearn if the U of the switch has worn isntead. Hence Brake pedal switch is not a on/off type switch, but a resitance switch that are not the same from switch to switch. So car needs to first lean the pedal not touched resitance, then pedal pressed down resitance next. To see if the pedal needs a relearn or replacement with relearn, Push the lower side of the starter button for 5 seconds to get the car into run mode/motor off, press the brake pedal down the normal amount that you are when starting the car and have someone see if the brake lights are coming on.
Hence if dials are sweeping, then BCM does have the car in run mode to start with (why you can jump the relay and car starts), but waiting on the Brake pedal push with trans in park conformation. before it going to send the signal for the relay to spin the starter.
And yes, if you replace the brake pedal sensor, will need to do a BPS relearn of the sensor to the car. the pedal untouched is easy to program in since you don't touch it, while when you do the pedal press to program that in, only press the pedal enough to just lightly get into the brakes, since your not going to be two footing the pedal to start the car.
As for run crank relay on the BCM, its on the bottom side of the module with the back up lights relay if the tech II is both showing that the trans is in park, and the brake is being pushed enough for the BCM, but relay is still not firing.
Lastly, if you are going to wrench on the car at all, then you need a Tech II.
If you have a laptop, then VX GM Nano will cover you for a tech II clone, and cost $109
Drop me a IM when you get it, and can get you squared away on installing the needed software on your laptop to get it to work correctly from the start.
As for no communication with the ECM, if the car started (not just cranked when you jumped the starter relay), then BCM is communicating with the ECM, and problem will be between the OBDII port and the BCM itself. hence have seen this a few times, where you need to clean the obdII port, and even pull the BCM connectors (battery disconnected) to clean them as well. Worse case if the HVAC box drain line clogged and it leaked water on the BCM out of the box as the box over flowed with water instead of draining out through the drain line, may have to pull the BCM board to clean up the Header pins,trances, and fuse relay clips on the board (maybe even a little re-soldering as well)
P.S, list your location since maybe someone close around you that knows the C6's to give you a hand, Hence your problem is easy to solve once you figure out the problem with a tech II, and in most cases, don't even need new parts. Hence if BPS just has a worn side on the U slot, BPS relearn will solve that until you get a new one to replace it. Getting to the shifter switch lever is no joy, but once you know its the problem, then pretty straight forward to bend the switch lever to fix it. Hell, Tech II will tell you if the BCM is sending the start command in the first place to crank the relay, so tells you if the problem is just the wiring itself. Hence may just need to pull the ECM connector (battery disconnected as well) to spray electrical clean then instead.
The black connectors on the silver box is the ECM and its connectors, while the blue connector you see, is the TCM and its connector on the back side of the ECM.
If you need to talk, then click on my name to the left to send me a PM or email with name and phone number, and I can give you a call. If you're in the Denver area, then can swing by with a Tech II to make quick work of resolving the problem isntead.
Hey FixForFun, did you ever fix your car and what was the fix?
Hey Dano, I'm a new member and don't have permission to send you a private message. I would like to call you if possible and quickly describe my situation. It's similar to the one here but a lot of history so a lot if I was to write everything.
Hey FixForFun, did you ever fix your car and what was the fix?
Hey Dano, I'm a new member and don't have permission to send you a private message. I would like to call you if possible and quickly describe my situation. It's similar to the one here but a lot of history so a lot if I was to write everything.
So my car started today. All I did was charge the battery for 2 days straight until the current being drawn was almost zero. So my first root cause could have been a bad battery even though Autozone checked it and said it's a good battery. The date is April 2020.
As soon as I plugged in the battery, the DIC was showing for Shift to Park. So I just fiddled the shifter a bit, DIC went away and car started.
So I think it was a combination of the battery might have been drained the first day I spent on it trying to root cause it. Because on the first day, I took the battery to Autozone, the diagnosed it as Good but needs charging. They charged it for 1-2 hours, I took it but no starting on that day. And the DIC on that day for Shift to Park wasn't coming all the time. So what I think happened on that first day is the battery kept getting drained sith all the LEDs and testing I was doing and the few times that the DIC Shift to Park showed, I tried to fiddle the shifter and restart the car but I'm guessing the battery was drsined by that time. Because by the end of the day during that first day, the LEDs started to flicker and I kept getting all kinds DICs. So at that time the battery must have been dead.
So now I will try to see why the shifter electrical contact is iffy. Not sure a switch is located there that maybe needs replacing or it's as simple as an electrical female terminal is aged and not fully bending right. FYI, this is what I mean by terminal, example from Amazon: 22-20 Ga. Female Metri-Pack Terminals, GT 150 Series, Sealed #12191818
And to root cause the shifter electrical contact, I did see that Dano posted here a paragraph and some photos about it: Shifter assembly showing the lever in park. Hence shifter has front contact switches that tells the BCM that the BCM is in park when the lever is all the way forward. To see if the lever contact switch needs to be adjusted, then just push the lever hard forward when you try to start the car, and if this starts the car, then will need to adjust the micro switch lever.
And to root cause the shifter electrical contact, I did see that Dano posted here a paragraph and some photos about it: Shifter assembly showing the lever in park. Hence shifter has front contact switches that tells the BCM that the BCM is in park when the lever is all the way forward. To see if the lever contact switch needs to be adjusted, then just push the lever hard forward when you try to start the car, and if this starts the car, then will need to adjust the micro switch lever.
More updates. I will not modify the contact switch of the shifter. I'm not that good at soldering and after seeing my shifter in action, I feel that the switch is being activated correctly. See the video below.
I am replying here from my phone and the video is somehow not uploading from my phone, ugh.
I knlw I haven't done any introduction of myself. I still don't want to type how this all started but to introduce myself, I have 2013 C6 A6, 60th Anniversary, with the below modifications (and the fuel pump motor is aftermarket too). I live in Michigan. And I am experiencing 4 issues: not starting 2 or 3 times in a row, connector bringing power to the cigarette lighter next to the ashtray isn't working so cigerratte lighter has no power, DIC is showing up for service tire sensor (after the dealer balanced the rear 2 tires), the Mild to Wild switch isn't working any more. I do have a Tech 2 clone with me lent from my friend. And I don't think these issues are related. Why? During the summer, the car never had starting or TPMS issues but the cigarette lighter never worked since I bought the car. The TPMS issue only showed up after getting the car back from the dealer after they re balanced the rear wheels. The starting issue only showed up also after I got the car back from the dealer.
So on 27 Dec, the car started once or twice and I left it at that. After I had charged the battery for 2 days straight, I connected the battery, the Shift to Park DIC came on, I put the shifter out of park and back in park and that removed the DIC and the car started.
Went to start the car and it did. I left it on for 5-10 min because I was trying to reset or re-learn the TPMS with the Tech 2. I couldn't fix the TPMS DIC. Also I did some trial and error with the Mild to Wild switch but couldn't figure that out too. I shut the car OFF and tried to start it again but it didn't. Could it be because the battery charge was down? But the car was ON so maybe the alternator wasn't charging it properly? Then I just started reading online more forums and of course Dano appeared again. Below are some screenshots I took of some important comments from Dano and others online that could explain what's happening with my situation. Currently I put the battery back to charge and will leave it overnight.
To comment on the 3 screenshots above I pasted from Dano and others.
Today, when the car wouldn't start, I kept staying inside the car with the Tech 2 connected and just reading different things in it. After some time, in addition to the TPMS DIC, I got the DIC Battery Saver Active. So clearly the battery got discharged and voltage dropped. I think the Tech 2 was showing 11.something but I didn't take a note. The actual # is not important, but I guess the voltage did get low so. Looking at the comment from the user talon90, I did probably stay inside the car with the igntion ON/engine OFF mode. So I will say that the 2nd or 3rd times I can't start my car is because the charge and voltage keeps dropping.
Looking at the other screenshot, I am probably doing what that says: in Accessory mode I am also pressing the brake and the selector apparently moves out of park. This might attribute as to why I can't start the car for a 2nd or 3rd time? Does anyone know when does the selector go back to park? Do I have to click the OFF button on the Start button to shut the car OFF first? Or do I have to move the shifter to neutral and back to park?
Also below are 2 photos of the battery. So it's a 8 month old battery from April 2021 so it's strange for it to go bad so soon.
To comment on another comment from Dano on another thread about BATTERY SAVER ACTIVE which I got today, his comments are showing in the screenshot below.
See Dano's last paragraph. So I'm thinking maybe I have this issue where the starter contacts need cleaning and the GND to the engine block needs cleaning. Unless all the time I spend inside the car are bringing down the battery charge enough to cause no start issues. Because during the summer I drove the car almost 2000mi and never had starting issues. At rare times I had the car stutter a bit before starting, maybe 4-5 times.
You have certainly been busy on this thread. You do realize it's a year old right? And that the OP only posted 5 times in four months, and hasn't posted anything for 8 months? Best bet if you're having an issue is to start a thread of your own.
You have certainly been busy on this thread. You do realize it's a year old right? And that the OP only posted 5 times in four months, and hasn't posted anything for 8 months? Best bet if you're having an issue is to start a thread of your own.
Hi,
Yes of course I saw the thread is old, I just assumed that people would still reply to it, meaning they would still get a notification that I posted. At this point I was talking a bit out loud so I'm gonna try some more things and then if still not working out then I will start a new thread. I just thought we weren't supposed to start a new thread if a similar one already exists.
C6 no crank / no start
