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I have an c5 from 1998. A few months back I started to get some weird problems. It started with ,shocks inoperate - maximum speed 128km/h. It just comes sometimes.
After that i started to get some other messages like , service needed, steering wheel service or something like that.
The warnings Dosnt come all the time , maybe 1/10 starts approx.
i tried to read about it and many people said grounding issue and ebcm module? Tried to clean the contacts with electric spray and check the wiring but couldn’t see anything.
The 1255 DTC is a BAD one. It says that your EBTCM has an INTERNAL PROCESSOR fault.
SOME TIMES, it can be cause by a weak battery. as well as the U-1040 DTC.
First things first, Have the battery fully load tested and see if it has the proper CCA, and reserve capacity. Sounds simple but, a low/bad battery will cause all sorts of weird issues. Eliminate that as a source. Its free and easy.
For the shocks inoperable, the F45 shocks can be deleted and replaced with a set of C6 shocks. Most prefer the C6 Z06 shocks, but C6 Z51 and C6 base shocks are also available at low prices of comfort is more of a concern than cornering performance. Although it sounds like you have a different electrical problem, probably battery related, if you have multiple systems reporting errors.
The battery was changed 3 years back to an red optima battery (expensive one). Shouldn’t be an issue but who knows.
The voltage meter shows stable 13-14 volts.
Might still be an grounding issue? I saw an drawing and discovered that I missed two (next to the front wheels).
As as for the shocks. I changed the original ones last weekend to z06 2004 ones. Same with stabilizer and springs.
If you changed it without programming out the F45 option with a Tech 2, that would explain why you are getting those errors. By the way, I would not trust the F45 simulators, they are hit and miss.
If you changed it without programming out the F45 option with a Tech 2, that would explain why you are getting those errors. By the way, I would not trust the F45 simulators, they are hit and miss.
Sorry. A bit new to all the expressions.
What u mean with f45option? And what is needed to be programmed? Is it something I can do by myself?
and what is tech 2? :-)
F45 is the option code for selective ride. If your center console had the option for selecting tour, sport, and performance, you had selective ride, which are adjustable shocks.
Tech 2 is GM's proprietary diagnostic unit. You can buy a knockoff from China for about $300, or try to find a local GM mechanic with a Tech 2. See here for instructions on how to remove it: https://www.corvetteforum.com/forums...post1571890692
The Electric Suspension Control module mentioned in that post is located in the driver cubby in the trunk.
the mechanic that changed my shocks told me there weren’t any cables connected to them. He saw the cables and they were disconnected and put in the wheelhouse.
I guess the previous owner disconnected them and either programmed them with an tech 2 device or put in some simulator plug-ins
i have to investigate more about it. My hottest clue is some grounding issue.
Some update.
Abs light is on and traction control light to. The fan dosnt start and I can’t see the display.
After i drove it for like 20-30 meters everything went to normal. Must be some contact somewhere that is malfunctioning.
If the HVAC Control head has no power when Key ON, Its is most time related to a defective Ignition Switch. Find the fuse for the HVAC and test it for power at key ON, If its dead then comes to life,, the ignition switch is most likely going bad. You need to replace the ELECTRICAL PORTION of that switch. You can keep the original key lock cylinder It just comes out after releasing it when its in the ON p[osition.
If the HVAC Control head has no power when Key ON, Its is most time related to a defective Ignition Switch. Find the fuse for the HVAC and test it for power at key ON, If its dead then comes to life,, the ignition switch is most likely going bad. You need to replace the ELECTRICAL PORTION of that switch. You can keep the original key lock cylinder It just comes out after releasing it when its in the ON p[osition.
BC
Is it possible that a failing key switch can give problems like abs light goes on and service vechile , shocks inoperative and service ride control also comes on?
Been reading forum posts so my eyes start bleeding. The key switch is possibly the root cause of my faults. Just printed your guide bill(damn nice work).
Im gonna dismount the switch later
today. I’ll update with pics and info how it’s going 👍👍
YES. There are several electrical contacts inside the ignition switch. Any or all of them (the ones that are actually used) can get damaged. Its usually only two contacts that get really nasty. Not every switch causes the same issues. Ive seen some that are really bad and some that only occasionally cause issues. I've see high mileage C5s with bad switches and LOW MILEAGE C5 with bad switches.
Make sure that your battery is 100% and then work on replacing or repairing that switch. Once you do that, you can reevaluate any remaining issue that you see.
I disassembled the key shift and as you said it was full of coat. Really black and messy.
Here is is some pics
I cleaned it up (first I did an mistake. I opened where the key cylinder was and all the pins and springs jumped out lol. Lucky I got them right back again.)
now it it runs perfect and no messages. (Hope it stays like that)
Really thanks for the help. And it was the most logical fault.
Some electrical problems
