canbus error and how to tell?

cheechy

cheechy

A2OC Donor
I've got the flashing heater plug symbol on the dash ever since I installed / mucked about with led bulbs on the rear light cluster. I installed LEDs as side lights previously with no errors.

Scan indicates it is something to do with cruise / break connection?

I managed to clear last night but it came back when driving into work this morning.

Ideas what it could be?
 
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cheechy said:
I've got the flashing heater plug symbol on the dash ever since I installed / mucked about with led bulbs on the rear light cluster. I installed LEDs as side lights previously with no errors.

Scan indicates it is something to do with cruise / break connection?

I managed to clear last night but it came back when driving into work this morning.

Ideas what it could be?
Click to expand...


You can't fit LED bulbs to the brake lights. The system senses a low resistance and so does not register the brake lights coming on and so it senses that there is an error in that circuit. It then throws up several warnings on the dash.

You get the same happening if your brake switch fails or if both stop bulbs blow

The only way to use LED bulbs in the stop lights is to add a resistor to that circuit (which defeats the object kinda)

So I would stick to conventional bulbs in the stop tail.

Steve B
 
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Yup thanks I already took them out but one remains on the right side fog lamp. I'll take that out to see tonight.

Btw can a mod change canvas to canbus please? Autocorrect!! I
 
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cheechy said:
Yup thanks I already took them out but one remains on the right side fog lamp. I'll take that out to see tonight.

Btw can a mid change canvas to canbus please? Autocorrect!!
Click to expand...

The fog lights will have no effect on this error.

You can use LEDs in the fog lights and reversing lights without problem.

Check that your brake lights are coming on when they should, perhaps you have misaligned the bulbs (easy to do on the rear light cluster)

I just about figured that you meant CANBUS !! LOL don't you just love the autocorrect (not)
 
So this one is driving me a little nuts now so might have to pick up new bulb housing and bulbs to see if I can clear.

I've taken the bulb out on the o/s frequently now and reseated. Error then clears then after a few miles it comes back...suggests a slightly difficult dodgy connection to me hence approach.
 
cheechy said:
So this one is driving me a little nuts now so might have to pick up new bulb housing and bulbs to see if I can clear.

I've taken the bulb out on the o/s frequently now and reseated. Error then clears then after a few miles it comes back...suggests a slightly difficult dodgy connection to me hence approach.
Click to expand...

It is very unusual for this to be triggered by one bulb, both need to be out before you should get the lights come on the dash!!!

Could it be that your brake switch is failing? When the pedal is pressed are both stop bulbs out, or just one / none?

One faulty bulb holder is not likely to be the cause but well worth sorting it anyway.

Steve B
 
It's a little bit weird. Never seen an issue with the bulbs really they seem to work fine.

Could be the brake switch I guess now you mention. Any easy way to check? Fir 2004 tdi what model number if brake switch would I have to look for? Seems to be a variety claiming to fit with different numbers!
 
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cheechy said:
It's a little bit weird. Never seen an issue with the bulbs really they seem to work fine.

Could be the brake switch I guess now you mention. Any easy way to check? Fir 2004 tdi what model number if brake switch would I have to look for? Seems to be a variety claiming to fit with different numbers!
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The test for your brake switch is easy, just get someone to stand behind the car while you operate the brakes with the ignition on !!

You might have an intermittent failure. I once "repaired" an intermittently failing brake switch by pressing the brake pedal down and then letting my foot slip off the side. Not the recommended approach but it was enough to reset the brake switch shaft. The other way is to depress the brake pedal and try to pull the plunger of the switch out towards the pedal slightly (they automatically adjust).

That can reset the throw and resolve the issue (unless the switch has actually failed!)

Steve B
 
Right so tried the first trick by using my hand and moving it off the brake a few times.

Error cleared will see if it comes back when I'm driving.

Fingers crossed and thanks for top tip as always :)
 
cheechy said:
Right so tried the first trick by using my hand and moving it off the brake a few times.

Error cleared will see if it comes back when I'm driving.

Fingers crossed and thanks for top tip as always :)
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Fingers crossed, but the error only triggers when you press the brake pedal when you are driving. (because it senses the car slowing rapidly without any sign of the brake lights. But you may be ok.

It is always worth trying the "free" things first.

Steve B
 
Birchall said:
Fingers crossed, but the error only triggers when you press the brake pedal when you are driving. (because it senses the car slowing rapidly without any sign of the brake lights. But you may be ok.

It is always worth trying the "free" things first.

Steve B
Click to expand...

Went for drive and it came back after about 2 to 3 miles :(

Scan suggests intermittent brake switch issue I'm beginning to think it's right!

So back to plan b...what type should I look for?

How about this? http://www.ebay.co.uk/itm/TO-CLEAR-NEW-INTERMOTOR-BRAKE-LIGHT-SWITCH-51672/311818457953?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649
 
cheechy said:
Went for drive and it came back after about 2 to 3 miles :(

Scan suggests intermittent brake switch issue I'm beginning to think it's right!

So back to plan b...what type should I look for?

How about this? http://www.ebay.co.uk/itm/TO-CLEAR-...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649
Click to expand...

That one is nothing remotely like an A2 one so steer clear of it.

You need one like this
http://www.ebay.co.uk/itm/FACET-BRA...154001&hash=item2800989cc0:g:IjsAAOSweW5VaY1u


Try pulling the plunger further out if you can (as I say, free fixes first) ;)
Steve B
 
Birchall said:
That one is nothing remotely like an A2 one so steer clear of it.

You need one like this
http://www.ebay.co.uk/itm/FACET-BRA...154001&hash=item2800989cc0:g:IjsAAOSweW5VaY1u


Try pulling the plunger further out if you can (as I say, free fixes first) ;)
Steve B
Click to expand...

I tried giving that a go but am feeling a little bit in the dark (literally and knowledge wise ) :)

Where is the switch in relation to the pedal? Assuming its behind but what sold I be feeling for our do I need to remove the trim?
 
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