Glow Plug Warning Light - help!

Zola

Member
Hi, I've recently been experiencing a slightly unnerving problem with the Glow Plug indicator light on the dashboard (A2 1.4TDi diesel, 75 bhp).

Recently, this light starts flashing on and off when I'm driving. It may come on for a few seconds, or for 5 minutes before going off again, regardless of whether the engine is hot or cold, idling or under normal road speeds, or length of journey. It comes on as usual for the quick preheat on ignition, then the light goes off as usual and the engine starts fine and the management system diagnostic always indicates "OK". This warning light then may or may not reappear on some journeys. There seems to be no difference in engine idle or performance or driving experience I can detect. The owners manual is a bit hopeless, simply saying "if the lamp should start flashing while movimg this indicates a fault in the engine management system. The engine should be serviced without delay". Well I'm about 2500 miles from service and would prefer to wait until the usual interval.

Any thoughts/help welcome! Is it ok to drive, should I book a service asap or ignore it, could it be a faulty connection or do I risk expensive damage?

Cheers, Z
 

spike

Member
Hi Zola
Unfortunately the glow plug light just gives a general warning and does not pinpoint a specific fault (I'm impressed that you actually checked the manual) From your description, it's likely to be a faulty engine sensor but a diagnostic scan is the only way find out just what the problem is. Generally no serious damage is done by rumnning the car with a sensor problem but its not ideal. If its not convenient to have this done quickly, i'd be tempted to have the service done early and have this checked at the same time.
If you just want a diagnostic check and are not too far from Richmond, N Yorks, I would be more than happy to help. If you are closer to Manchester then i'm sure the ever helpful Mike (Skipton 01) would do the same (sorry to keep volunteering you services Mike)

Cheers Spike
 

Marco77

Member
I've just fixed this on mine it was flashing changed the glowplugs didnt resolve stuck on vag com and it said there was a fault in the brake light switch.

sure enough when it was flashing when pressing the brake the lights did not work and when it wasn't flashing they were working.

did a search on other vag forums and it came up the same warning for this flashing glowplug icon

part cost £8.64 from audi took 30mins to fit myself and the flashing glowplug
stopped
 

Zola

Member
Guys, thanks for this, and I've now seen some other threads so it seems quite common. I'd love a diagnostic, Skipton kindly did me one a couple yrs ago, however I've a hunch that it's this brake light thing which seems both bizarre and a bit of a worry for a rear end shunt, so I'll book an early service. Interestingly I did 140 miles yesterday over a range of roads and conditions. The light did not come on until 108 miles and went off at 114 miles and did not reappear on the journey.
 

Marco77

Member
yeah when i did the diagnostic check it show fault brake light switch intermittent as it was just random
 

stico

Member
Glow Plug Warning Light

Had the same problem with the glow light flashing a few seconds after i start the engine also the led brake light half of it stayed on slightly. Took it to my friend who deals with VW's and told me straight away that i had no brake lights both bulbs had gone living the side lights working.
 

Bill0712

Member
Glow plug warning light

Thanks chaps, just tested my brake lights after reading this thread about flashing glow plug lights, guess what? Flashing glow plug light equals no brake lights again. will check the switch. Bill.
 

bobsimes

Member
brake light switch

when my brake light switch was on the way out i noticed i also got interference on fm stations when the radio was on and i was driving??

changed the switch £6 ish and its never happened since.

just a note to add into this thread, it may assist someone??

Simon
 

kiddy5

Member
Thanks every1, just going to change brake light switch wondered why i did nt have any brake lights!!! Cheers
 

kiddy5

Member
Can any 1 help further as im losing the will!!!! Changed the brake light switch with a replacement and to no avail, audi replaced it with another black 1 but having read some posts is the green 1 much better??? Cheers!!!
 

MikeMarsUK

Member
These switches can be quite fussy about installation, if the piston doesn't lock into the correct length. It took me several goes to get it right. I gather you can pull the piston back out on the black ones to allow it to be refitted.
 

zipnjeff

Member
Hi .. just had this problem on mine .just read this thread on the forum .. i changed the brake bulbs yesterday to leds ... have now taken them out and cured the problem .... wont be usin them again lol ... panic over ... love this forum ... any answer or hint i need is on here ... thanks guys .
 

Birchall

Dick Chown Award 2016
Hi .. just had this problem on mine .just read this thread on the forum .. i changed the brake bulbs yesterday to leds ... have now taken them out and cured the problem .... wont be usin them again lol ... panic over ... love this forum ... any answer or hint i need is on here ... thanks guys .

Yes, it is a shame that you can't fit LEDs in the stop and tail or indicator bulbs (unless you fit resistors and that seems to take away the benefit of the LED bulbs)

You are ok to fit reversing bulbs, fog lamp bulbs (front and rear) they don't even show as a "bulb out" on a DIS equipped A2, but indicators and stop/tail need some kind or work before you can use them.

I have some ideas about the indicators and I am discussing this with the Audi A2 electronics guru (more on here if /when we crack that one!)

Steve B
 
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I had the flashing glowplug in the week, googled it, and came right here. Quick phone call to my garage, then in today for a quick diagnose. Only one fault: brake light switch, which they had got in following my call, so all done and dusted in half an hour.

Thanks guys!

(During the MOT a few weeks ago, I had observed that the centre LED brake light was flickering, although the bulbs in the clusters were fine, so the brake light switch info wasn't entirely a surprise.)
 

damadgeruk

A2OC Donor
Just located this old thread following the installation of my second led side/brake lamp, looks like I'll be returning to one of each, for the time being at least. :)
 

Birchall

Dick Chown Award 2016
Unfortunately you cannot use led bulbs in the rear tail/stop lamp without resistors.

The ABS system senses the bulbs coming on when you are braking. If your brake light switch or if both stop bulbs fail you will get the dash lights coming on such as the glow plug etc.
With LED bulbs the current drain is so small it thinks the bulbs have blown.

So unless you fit resistors to the brake side of each bulb (or possibly just one side) you will have a problem but with resistors fitted you lose the whole point of having leds in the first place.

Steve B
 
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hdlo

New Member
Unfortunately you cannot use led bulbs in the rear tail/stop lamp without resistors.

The ABS system senses the bulbs coming on when you are braking. If your brake light switch or if both stop bulbs fail you will get the dash lights coming on such as the glow plug etc.
With LED bulbs the current drain is so small it thinks the bulbs have blown.

So unless you fit resistors to the brake side of each bulb (or possibly just one side) you will have a problem but with resistors fitted you lose the whole point of having leds in the first place.

Steve B
What is the issue with using a resistor? My 1.4 TDI has an alternator with 120 amps.. It couldn't care less whether that brake light draws 1W, 5W or 50W for that matter... Main benefits of LED brake lights are reaction time, visibility/brightness, longevity, low power draw. In that order :)
 

Birchall

Dick Chown Award 2016
No issue, but the main idea of LED bulbs is because they are very low drain. So I can’t see the advantage of adding resistors and so making them “normal drain”. Not only that but I have seen many examples of where the heat from the resistors has melted plastic surrounds. So if there is no advantage why bother with having to wire in resistors, especially when you run the risk of them getting hot. Just look how hot a normal car bulb gets (if you have ever tried taking one out that has been lit. Very hot. So why just transfer that heat to a resistor!

But each to their own. I am a strong fan of LED bulbs in a car, but I am not a fan of resistors..

Steve B
 

audifan

A2OC Donor
As the A2 predates LED lights the systems need to see a higher power draw. This is the reason that some LEDs need resistors. TBH brake lights are one application I would not fit LED and stick with the existing configuration. Steve B has already explained about the ABS, traction control, ESD and others that are linked. That is why the glow plug flashes when it detects a bulb or brake switch problem as it is critical for all the systems to work. I like LEDs just not for the brake lights on an A2.
 
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