'vetteguy99

I recently bought a 99 C5 from a friend and i've come to the conclusion that I need to clean all my grounds but before i dive into that, I want to get some more input on the random things happening.

Left turn signal when clicked down and brakes are applied, the blinker in the dash stops flashing but once I take the brake off, the blinker continues as normal. The right blinker is completely unaffected by any of this.

I pulled some codes this weekend and pulled a P0705 (Transmission range sensor A Circuit Park/reverse/drive/low input) Every now and then, when the car is in park, it will blink across the dash, "brake before shift". I dont know if these are somehow related or what.

I pulled some ABS codes too

C1255 EBTCM Internal Malf ABS/TS Disable
C1232 Left Front Speed Circuit Open/Shorted
C1224 Right Rear Wheel speed equals 0

I've also got some humming when the transmission is in park and the speakers pop when I put the car into drive or any other gear.

Any and all help is greatly appreciated in this matter.

Furthermore, i'll be digging into some stickies to see if they can help me out.

Thanks guys!

dadaroo

With regard to your blinker issue, do the actual lights (front and/or rear) reflect what the dash is doing?

With regard to your codes you failed to indicate if they were H, C, or H and C. Not sure if the C in front meant to indicate C. Need to confirm.

'vetteguy99

here is pictures of codes

dadaroo

The code C1255 is called the code of death for the EBCM and rarely can ever be corrected or fixed. That means you have no ABS or TC or AH if you have that option. EBCMs for the early cars are no longer available from GM and VERY hard to find in the used market and then you have to hope they will work.

Forget the Actron scanner, it will only provide limited codes. You need to learn how to pull your codes from the dash. Pulling the codes from the dash will also tell you if they are History or Current.

Video:

READING YOUR C5 Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs

Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

NOTE!!! Start the car and let it idle. Then take it for a drive and cause the problem to occur. When you return home pull the codes BEFORE you shut off the engine.


Do NOT discount the codes with the H following them. They can provide an audit trail for issues going on with the car. They ARE important in diagnosing problems.

Post ALL the codes that you pull with the engine running..........

Some codes go away WITHOUT setting an H code when you shut the engine off. I suspect you will have several codes that will show C or HC that do NOT show when the engine is turned off.

'vetteguy99

TCS C1232 H C
HVAC B0363 H
BCM B2723 H

These are the codes that popped up currently.

RadnessWarrior

For 1232, I just fixed this code on mine.

Take the wheel off and follow the wire coming from the hub to the lower subframe. Check it for a break in protective casing. I found that mine was either chewed or torn up from something else. I replaced the wire and wrapped it up and was good to go. I also have an extra sensor pigtail (from the hub to main harness) if you want to try it out! Good luck!

dadaroo

Until you do this, clear/reset the DIC codes and see if anything comes back. I would assume the TCS one will but sometimes a reset can clear up even C issues.

RadnessWarrior

The code would reset, then immediately come back on. That was my sign

BigGun

That's way different from what you started with! Have you driven the car much since the codes were originally pulled? All these are fixable. Hope you don't see the C1255 back.

'vetteguy99

I have not driven the car since yesterday and that's when I pulled the codes. I will be driving it this evening and just ordered a new abs harness to see if it fixes the problem for the TCS code. As for the others, I have no idea how to fix them besides the vague info I got from google.

dadaroo

Well, I asked you a question about your brake/turn signal issue but have not seen a response.

'vetteguy99

I apologize for that. The exterior lights and dash lights all do the same thing when the turn signal is used.

dadaroo

The turn signal circuit and the brake light circuits go thru the Multifunction Switch on the steering column. I think that is your issue. If there was some issue in the Hazard switch it would affect both sides, not just one.

The turn signal bulb filament is also the stop/brake light filament. The two circuits for each function come close together in the MF switch. Seems like there is an issue on the one side.

If you need guidance on how to replace the MF switch let me know.

'vetteguy99

Yeah I need to try that. A walk through or guide to help replace it Would greatly help out right now.

I need to post up the new codes that have popped up as well. The 1255 code that someone mentioned earlier has not come back either.

dadaroo

Here is the link to the MFS replacement:

https://www.corvetteforum.com/forums...-a-how-to.html

'vetteguy99

after driving for a few days. here are some new codes. i'm going to assume that the ones with "C" next to each code are the ones currently being triggered. I have a few things on order to fix some of them and should not be a problem. Thanks guys for helping me find all the little nick nacks and such. It's definitely getting fixed up seeing i am owning my first corvette and only just bought it back in december.

C1221 H
C1224 H
C1232 H C
B2583 H
B2723 H
B0363 H
B0441 H C
B0446 H
B2860 H C
U1096 H
U1064 H
U1016 H
C2105 H
C2110 H C
C2115 H C

'vetteguy99

so I replaced the headlight switch and still getting the same problem when i turn the left turn signal on and press the brake, the light stops flashing. i'm going to go after the brake light switch next and hopefully that's the culprit.

dadaroo

Would have thought the issue was there. YOu can try the brake switch but if an issue was there I would expect it to affect both sides.

Are your bulbs all original incandescent style?

'vetteguy99

I've replaced all my bulbs in the rear. Another thing I found out last night while my neighbor was helping me is my hazards don't work in the rear at all but they work in the front. The Hazard switch also gets stuck but does take a little effort getting unstuck

dadaroo

The hazard switch function feeds the fronts differently than when you use the turn signals. I don't think it is your issue. It may have an internal issue when using the hazards but if it provides turn signal functions then I still think it is not the problem for this issue.

I asked about the bulbs to see if you had LEDs, which apparently you don't.

At this point. I think your front left turn signal has issues. It is probably in the socket or connector. These serve also as the DRLs. Heat can cause the housing to melt and develop a hole above the socket that lets water in.

These kind of issues can be challenging to find sometimes. At least removing the bulb and socket is not hard. Here is a video on it. If you need to remove the housing later we can provide that info also.