citekare

Hello All,

I have a 2004 C5 with the MRC shocks that were leaking fluid, one of which was bad enough to drip on the floor of my garage. With the cost of new MRC shocks, I elected to change over to Bilsteins which ride beautifully, and better than my factory shocks ever rode. Before I went forward with the swap, I'd been searching the forums here and came to understand that the code for the MRC option could be altered to remove the DIC warning and 80 mph hard limit so I had the shocks replaced. Afterwards to my surprise, and to the shop I took her too as well, they said the 2004 computer cannot be modified to remove the code for the MRC option. Earlier years in the C5 can be altered, but not the 2004. Is this true?

If this is true, can anyone recommend shock simulators that can be plugged into the harness to remove the DIC warnings and the 80 mph limit? This would be for the F45 option, as I understand the F55 option starts with the 2005 C6 model correct?

If the computer cannot be altered to remove the F45 code, and the simulators don't work on the F45 option, does the 10 amp/10 ohm resister trick work on the 2004 C5?

I appreciate any assistance. There is such a wealth of knowledge here, with a few contradictions which can be somewhat confusing so I apologize in advance if this post seems repetitive.

Thank you!

02torchred

IIRC, F55 (real-time dampening) started in 2003. F45 could be tricked with resistors, not the F55. A tech II programmer can delete the F55 codes, a lot of people have done it here on the forums, including Patches, a long time member. Some people it didn't work for though.

https://www.corvetteforum.com/forums...nd-25-a-2.html
https://www.corvetteforum.com/forums...uspension.html
https://www.corvetteforum.com/forums...post1587979576

citekare

Thank you 02Torchred for the clarification on the F45 and F55 options. Did the F45 and F55 systems overlap at all between the end of the C5 run and the start of the C6 run? My selector switch for "Tour" and "Sport" is on the console if that helps determine which system my vette has.

Using the VIN decorder, neither of the options are detailed in the list of options on my vette, but it certainly has one of them. My VIN is 1G1YY32G645114576 in case that would help any here. Since my shop said they couldn't delete the codes for the system I'd like to use the simulators so I just need to identify if I have the F45 or F55 system. Looking at the parts and accessories available for the C5 as part of the forum here there are F45 simulators for the C5 and F55 simulators for the C6. If the F55 could be used on the C5, I truly don't know which simulators to research and buy.

Any assistance is appreciated. Thanks!

GCG

F45 has 3 selectable settings and its last year was '02. F55 has 2 settings and began in '03. Check your glove compartment sticker for RPO code F55.

F45 can be tricked with simulators. F55 has to be disabled with a Tech2, as mentioned above.

citekare

Thanks GCG, the sticker was right there in the glove compartment lid, and F55 is part of the list of codes. If the F55 can only be disabled using the Tech2 to remove the codes from the computer, I'm not sure why Corvette Masters here in Maitland FL. could not remove the codes. Maybe they have the wrong tool?

I'll call them to double-check what problem they had and see if they can try again.

Thanks for your help. I thought I had looked everywhere for the data, and never thought there would be a list of codes in such an odd spot.

GCG

Glad to be of service!

Check the links above in Post 2. The procedure to delete F55 is clearly given in a step-by-step sequence. A Tech2 is a must for this.

Notover

I just went through this on my 03. I removed the MRC shocks (F55) and replaced them with the C6/Z06 shocks. The Chevy dealer used the print out I brought along from this forum and deleted the F45 option. That's right, the F55 option does not show up on the TECH II when plugged in. Have them search for the F45 option and follow the procedure outlined here on the forum. Your dealer may not have the latest updates for the Tech II. They are very costly and most GM products no longer use the TECH II. Most use a laptop program now.

red50th

OK, wow very confusing. So I have a C3. Do I understand correctly you would disable the F45 option using the techll even though the C3 is an F55 option. So you delete the F45 even though it’s not really in the C3 system.. So as I read, the tech ll does not recognize the F55 when hook up to the C3 but it shows the F45 option and you delete that? Next you mention most techll are no longer at dealerships now and they use computer. Does the computer have this option to remove the F55 option. Also, it’s my understanding the real time tampering shock system F 55 started in 2003 continuing on. I have seen there are direct plug-ins to trick the system but those are only in 2005 and onward and pre 2003. So 2003 and 2004 years are the troubled years which cannot be altered or tricked bypass correct?