My b-up lights come on as soon as car starts and remain on. I can disable them by pulling relay.

The car is a manual. I've replaced the relay and the reverse switch on the trans. Neither made a difference.

Please help.

 

Don't have my manuals with me. I will look into it as soon as I can if no one beats me to it. Hey, you have forward and backward running lights!

 

The BCM also controls the lights and can turn them on without the car being in reverse:



Make sure that the BCM isnt commanding the lights on for some reason. If it gets wet, it can have all sorts of issues

 

I've got a code reader that I've used for some basic resets. Can I use this to see if the Back-up lights are turned of in the BCM.

If so what do i do.

 

NO, A common DTC reader will NOT show you what is happening with in the BCM other than displaying the Diagnostic Trouble Codes (DTCs) that the BCM is throwing. Some will not even display BODY Codes.

You would need a GM Tech 2 to be able to interface with the BCM.

You can use a common DC Volt meter to figure out what is going on with the relay.

Check this out!


YOU DONT NEED NO STINKING CODE READER!


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.

 

I also have a B/U light issue with no codes from DIC. Maybe these issues are somehow related. My B/U lights intermittently won't flash when locking the doors and fail to come on when opening the door with the fob. I have the DIC programmed for lights only. I bought a new fob and now am about to replace the RFA module which is the receiver for the keyless system. You may want to see if your #2 fob does the same thing and both have a fresh battery.

 

The FOB and RFA has nothing to do with the back up light operation..

If the FOB transmits and locks and unlocks the car opens the trunk and sounds the panic alarm,,, its doing all it can do.

Its communicating with the RFA and the RFA is telling the BCM to conduct what ever entry functions you have in memory.

The BCM and the way its programmed does the rest. All the FOB does is transmit to the RFA and the RFA tells the BCM that you are entering or leaving the car or want the trunk open or the panic alarm on. The BCM starts the routeine for what you fob commanded.

I SEROUSLY doubt a new RFA will do anything for you.

 

I have the same problem with a 2003 , did you ever find the problem?