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What are error free led bulbs and why are they needed?

15K views 14 replies 4 participants last post by  Avel Du 
#1 ·
What are CAN-bus Error Free LED bulbs?
CAN-bus Error Free LED bulbs are LED bulbs that have resistors that are internally/externally attached. European vehicles are the typical candidates for these types of LED bulbs as the electrical system on these European cars have sensors that detect whether the light is working or not. Since LED bulbs draw far less power than the stock filament bulbs, the vehicle’s computer may think that the bulb is out so it'll throw an "error message" or "bulb out" warning the driver that the light is out; thus the name "error free". The resistor’s job is to mimic the power draw of the stock incandescent bulbs to trick the computer to think that the bulbs are drawing the same rate of power so the vehicle does not throw any error messages.

Do I need error free bulbs?
If you own a European vehicle, you will most likely need error free bulbs. Many European vehicles such as Audi, Mercedes-Benz, BMW, Range Rover, Jaguar and many more use a CAN-bus (controller area network) system that monitors the activity of lights on the vehicle to detect if they are operating or not.

Since LED bulbs draw far less power than the stock bulbs, the vehicle’s can-bus system detects the low power draw and determines that the LED bulb is faulty. To stop this from happening, error free LED bulbs have resistors that are built into the light which mimic the power draw of the stock bulb which stops the error message from occurring.

Error free LED bulbs are most commonly used for exterior lights such as the turn signals, head lights, parking lights, license plate lights and more. Interior lights typically do not need error free bulbs, but for certain vehicles, it is required.


I have error free bulbs, but they still throw an error, why?
With vehicles that require error free LED bulbs, there is a specific way to install the lights to make sure that there is no error message. Please follow the steps below:
1. Take out the LED bulb and replace it with the stock bulb, turn on the vehicle, and confirm if the error message is cleared.
2. Turn off the vehicle and re-install the LED bulbs (make sure it is the correct side of polarity or else the vehicle will record the error message again). If the LED bulb is installed, but the polarity is incorrect, you will have to start the troubleshoot again from step one (1).
3. Close all the doors (trunk and hood if open as well), lock the vehicle, and wait 10-15 seconds. After this period, start up the car and turn on the lights to check for the error message.
This is a strange procedure to do, but what we have found in the past is that it does work out well for majority of the vehicles we’ve dealt with.
 
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#4 ·
If the led fails, you will get a dash message like
front side marker bad or whatever the terminology is

bad is bad, whether an led bulb or not

is that your question? :D
 
#5 ·
@jbanks15

That's the way I would hope it would work. But, a CANbus Error Free LED is error free because there is an additional resistor in parallel with the LED, not in series, to provide a current that is detectable by CANbus. It looks to me that if the LED fails, current will still continue to flow thru the resistor. Therefore, the CANbus would not detect a failure unless there is something in the integrated chip that cuts the current to the resistor.

I guess my question boils down to this: Have you experienced a failure of a CANbus LED and has CANbus identified the failure?

Thanks,
Greg
 
#8 ·
led plates are 10-041
trunk interior are 10-105
parking lights were 10-036
footwell were 10-092
 
#9 ·
Thanks, Jeff, P/N's are very helpful.

Regarding headlights, I think you might have done the full fixture replacement with SPYDER. If not, did you replace any of the lights in the OEM fixture? I understand that there is a beam pattern concern with replacing the bulb in the projector lens, but I might consider doing the high beam, turn signal and fog.

And while on the subject, did you replace any of the rear lights, such as the backup and turn signal?

Thanks for your time and Happy Thanksgiving.
 
#13 ·
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