C5 starting issue

[teamzr1]

IF after trying to start multi times and no other DTCs trip then Yes, maybe the starter solenoid or loose wiring to it
Kinda a bitch but starter is on passenger side of rear of block
Maybe a burnt spot on solenoid and tapping on it maybe enough to get off that spot just as a test
and if engine starts your off to rebuild or replace it

Any time there are U comm DTCs someone on the Starbus yacking and not allowing other controllers to talk in the network
Having seats out will clearly cause the DTCs to return even if you clear DTCs
Still is a question if Security/VATs is playing a part and relay noise, again bad cell of battery cannot handle current load and have problems with loads on relays

Yes the LEDs replacing DRL can cause DTCs,

In any case as to the ground splice packs, and other main ground points a good idea to clean and make sure good tight connections as
the controllers in many cases control functions not by voltage but reference to ground

BTW, if auto tranny do not forget the park switch and if out of alignment engine no start

This forum does not allow large content in posts and there is a lot of DTCs for controllers
so go to my Tech Forum, see most of them but click on the link there and download all of them in a PDF file
C5 DTC Trouble Codes

Image of starter and solenoid

 

[Vetteheadtony]

Hi Andy I’m in Felsted near you, got a C5 Z06 also got some knowledge and also got a Tech 2 factory diagnostics
Call me 07816878892 Tony

 

[Andy1B]

Thanks to all that replied with advice and information. Turns out it was the starter motor (or solenoid) and BIG thanks to Vetteheadtony for coming to help. (Actually he did most of the work!). Couldn't get it going by tapping/loosening/shaking the starter. Once we got the starter out (not easy on your back on a gravel drive!) we did get it to spin but it was stiff and graunchy so decided to replace it. Again big thanks to Tony for guiding me to Rock Auto in USA. Ordered a factory reconditioned starter at 4 pm Friday 21/08 for delivery the following Friday. Email confirmation said delivery would be Thursday and it arrived Wednesday afternoon. Total cost including recon surcharge for not sending back the old unit, Vat, delivery, 2 exhaust gaskets and credit card currency fee £153.30.
If anyone else has a similar problem or needs to change a C5 starter I recommend the following:
1. Don't do it on a gravel drive!
2. If you don't have access to a hoist raise the car as high as possible. Use axle stands. There are side jacking points between the wheelarch and front of door if you can't get a jack under the front. You'll need a block of wood if you don't have the 'hockey puck'. We also raised the rear slightly but more height would have been easier.
3. Disconnect the exhaust all the way back: Both manifolds, front bracket on bellhousing, mid bracket with springs just before exhaust separates to go over axle, rear brackets under rear valance. We managed to get the starter out while leaving some of this connected but it was tough and I couldn't get the exhaust back onto the manifold without disconnecting the rear then starting to reassemble from the front, so easiest to disconnect it all anyway. It also needed liberal amounts of WD40 as it probably hadn't been touched in 16 years.
4. With the new starter fitted start the car with the exhaust still off. It sounds great and the neighbours loved it. Honestly!
5. Forget all the previous frustration. Take it for a drive and delight in a job well done.

 

[z06_tim]

Nice one guys. Job jobbed, and good tips and tricks for any C5 owner on here.

 

[Firepit]

This is a pretty useful post. Thanks for sharing. I've got some electrical issues which I'll stick under a new thread

 

[Andy1B]

This is a pretty useful post. Thanks for sharing. I've got some electrical issues which I'll stick under a new thread

I'm pleased to report that since changing the starter motor I've not had any further starting issues. The battery does run down if I leave the car standing too long but I've improved my habits of starting and running the car more regularly. Hope you get your problem sorted.

 

[Firepit]

Hi, thanks!

I’ve had mine about six years with one of the yellow top battery’s always on a battery tender thingy. And it’s always started on the first crank. I’m going to go through some trouble shooting when my new multi meter arrives. I’m not an expert, far from it. And I only have a tiny garage so this isn’t fun .