Audi A4 Cabriolet - Roof warning light flashing 10x

[wiffers]

Hi guys, I'm new here, and just bought my Audi, expect my welcome post soon :o

I have a 2006 A4 3.2 FSI Quattro S-line. - B7.

Anyway, the roof works perfectly. But when I turn the engine on I get 10 flashes of the warning light.

Had the faults read
02000 - Switch position inplausible
01986 - Convertible top frame position sensor (G356) - electrical fault in circuit
00532 - Supply voltage B+ lower limit exceeded
(top frame poition for G356 was 237)

I had them reset, put the roof on and off a few times, no light at all.

Drove for week or two (perhaps 5-7 roof cycles) - all OK

Now come back on again!

I've looked at the top frame position sensor (on one side at least - are there two?) and it looks to be plugged in and hasn't broken. The whole system looks pretty tidy.

Seems silly buying a sensor if it's not that.

've only used roof with engine on.

Any ideas?

Thx

[wiffers]

Streamlining posts

[wiffers]

bump

[Sam]

Have the codes also returned?

[wiffers]

That was my next step - to find that out. I'd imagine a code has returned, and I'm assuming the same, but need to check that out.

[Sam]

;)

There's a manual roof reset procedure which may clear the warning light, but I suspect there's something else amiss.

Reset procedure is detailed in this thread; How do you reset automatic roof? (http://www.vwaudiforum.co.uk/forum/showthread.php/73229-How-do-you-reset-automatic-roof)

[wiffers]

Yeah, I saw that, but thoiught it's stramge having to manually wind it when the roof actually works. Could be worth a pop I guess.

I did reset the light, but it came back.

I'll try a manual reset and read the codes again I guess. It's just weird getting an error when it all works.

[wiffers]

Have the codes also returned?

Hello mate, just had it read/reset with VCDS, and the codes were as follows:

02000 - Switch position - 008 - implausible signal - intermittent
01986 - Convertible top frame position sensor (G356) - 012 electrical fault in circuit
01988 - Convertible top operation switch (E137); Close 012 - electrical fault in circuit - intermittent

The roof works fine - not done manual reset yet.

Any ideas?

[wiffers]

Edit - manually reset roof - fingers crossed

[wiffers]

Warning light back , but took a few cycles to do so
getting this
01986 - Convertible top frame position sensor (G356) - 012 electrical fault in circuit

But sensor looks OK?

Time to replace it?

[wiffers]

SOLVED (I think):

As above the sensor in question was G356 (error code 01986), but as roof was working I assumed sensor couldn't be completely shot. Linked to VCDS and looked under section 26 (auto roof), cleared code, then plotted real time graph of output from G356. It went down lots, slightly up, then down (as it should) but didn't look smooth, and every cycle or so it spiked down to 0.

So I figured that as it's a variable resistor that doesn't get used much, and only moves a little, it could be dirty tracks giving bad connection.

So took it off (1 screw & 1 connector so 30 seconds), it felt a little rough, so squirted wd40 in the gap, and wiggled end to end about 200 times. Much smoother.

Reassembled, manually reset roof. And opened VCDS again.

Graph for G356 when roof opening and closing is perfectly smooth, with no spikes up or down.

Done 10 cycles so far, no error code.

Fingers crossed