Blinking light between Drive and 4th gear on a 986 Tiptronic

[ikkaro]

Hi,

The below issue is for an 2002 tiptronic.

I recently fixed the secondary air injection system (it had the following codes: p0446, p0410, p1410 and p1130).

This is the second time I fix this problem, and the second time the following happens:

The gear indicator blinks/alternates between "D" and 4th gear. It only does this once the car reaches the normal operating temperature (I tad above 180). The fault code says that it is the "coolant shut off valve." The mechanic had not seen this before, any clues as to what this might be?

Thanks for any input.

IK

[ClaudeJS]

Dear Ik,
Same phenomena happened to me last week: I left the battery disconnected for almost 2 months, until last week, reconnected, start the car => everything OK.
After a few miles I discovered that blinking light between 4th ear and Drive.
The car is running fine, no problem with the auto gearbox, except the manual mode is not working. I cannot shift gears from the steering wheel.

Any idea?
I read in the forum, maybe the multi-function switch is the culprit?

Help welcome!
JC

[Lil bastard]

The lights flashing as you describe indicate a fault in the tranny. The coolant shut-off valve is operated electrically, so your fault may be as simple as a blown fuse - check the fuse panel for the appropriate fuse. It could also of course be a faulty shut-off valve. This can be checked by jumping the pins appropriately in the trunk control box - this procedure must be done in order to flush the cooling system. If the valve opens when jumped, it's working properly.

Another somewhat common cause of this fault is a dirty switch at the tranny. This gets exposed to mud, water, dirt and can become inoperable - usually accompanied by an inability to operate the tranny in manual mode. You can pull the switch and clean it up, fairly simple DIY.

Cheers!

[ikkaro]

Originally Posted by Lil bastard

The lights flashing as you describe indicate a fault in the tranny. The coolant shut-off valve is operated electrically, so your fault may be as simple as a blown fuse - check the fuse panel for the appropriate fuse. It could also of course be a faulty shut-off valve. This can be checked by jumping the pins appropriately in the trunk control box - this procedure must be done in order to flush the cooling system. If the valve opens when jumped, it's working properly.

Another somewhat common cause of this fault is a dirty switch at the tranny. This gets exposed to mud, water, dirt and can become inoperable - usually accompanied by an inability to operate the tranny in manual mode. You can pull the switch and clean it up, fairly simple DIY.

Cheers!

Thank you so much for the advise. I am going to the blown fuse first, as the car just had the cooling system flushed (so I assume the shut-off valve should be ok). Will post back with results.

Cheers,

Raul

[ClaudeJS]

Maybe useful for all:
With an OBD code reader, I found the code P0740 "Torque Converter Clutch Circuit/Open"
I erased the fault and problem is gone, solved : no more light blinking, everything works perfectly!

So simple as that!

Lesson learnt: OBD code reader is mandaotry!

Thanks to all for the support,

JC

[Dale_K]

Simply erasing the code may not have corrected the underlying problem. My car is in the shop right now and one of the items is the 0740 code. I am hopeful that a Tiptronic service with fluid and filter replacement will have a positive effect on my car but I really won't know until I drive the car for a while. I hope your car doesn't need any additional work but simply clearing the code might not be enough. My mechanic thinks the Tip fluid gets contaminated with diff fluid and then the torque converter clutch slips. Personally I doubt it. I told him to go ahead and take a fluid sample for lab analysis but I don't know if they can really detect cross contamination or not.

I'm supposed to get my car back early this week and I'll post an update. It would be good news if the Tip service decisively fixed it because that's fairly easy and cheap. Stay tuned, as George Bush the elder used to say.

[bcorcoran]

Hi, I've just joined this forum - grate source of info.

My 2001 Boxster S tiptronic has similar symptoms: some gearbox slip & alternating fault lamp indications.

I'll have to look up the fault code provided from my dealer but their suggested fix was a gearbox overhaul as they claimed the torque converter was worn and residue evident in pan. I took the car to a transmission specialist who had trouble identifying any problems but we agreed to an oil & filter change and some further fault diagnosis. The specialist indicated no one had removed the pan previously and no evidence of residue from torque converter.

The filter & oil change improved the situation for low speed driving but at higher speeds I still get fault lamps, but not always and no slip, no noises, no fluid loss, in fact no change in performance ie can manual shift as normal.

From this forum & others it seems possible causes include wheel speed sensors, transmission plug/sensor or transmission control unit on boot (trunk) wall.

I hope others out there can sort this one!

[Malty123]

Originally Posted by Lil bastard

The lights flashing as you describe indicate a fault in the tranny. The coolant shut-off valve is operated electrically, so your fault may be as simple as a blown fuse - check the fuse panel for the appropriate fuse. It could also of course be a faulty shut-off valve. This can be checked by jumping the pins appropriately in the trunk control box - this procedure must be done in order to flush the cooling system. If the valve opens when jumped, it's working properly.

Another somewhat common cause of this fault is a dirty switch at the tranny. This gets exposed to mud, water, dirt and can become inoperable - usually accompanied by an inability to operate the tranny in manual mode. You can pull the switch and clean it up, fairly simple DIY.

Cheers!

Ive got the same flashing D and 4 lights, Where is this tranny switch located to check it?

And which pins need shorting to operate the coolant valve to check that?

Thanks

[tonythetiger]

I will revive this thread rather then start a new one.
2002 tip, 986 S with 80K

Flashing 4th and D after warm up, however transmission works fine and the normal lights come back in a minute or so, go to 4th and D again, etc as I drive. Automatic and manual function fine, just dont get the feedback in the dash lights when its out.

I have heard this could be the transmission’s coolant vacuum valve. Does this circulate coolant through the transmission? That seems to be the simple fix and makes sense.

I had the transmission serviced, new fluid, filter etc about 6 months ago, but the problem didn't completely resolve. Now with the warmer weather, I'm thinking I should iron out this issue.
I have a durametric scanner, but it only shows alarm fault codes (historic, none present now) to be honest, I am not sure I'm using the durametric to its potential, it seems pretty lame when I do the short test on all modules, so I would welcome advice on this as well.

[tonythetiger]

to add to my question...would a faulty coolant vacuum valve potentially lead to heat issues with the tiptronic, manifesting in the 4th and D flashing?

[snottas]

Had the same problem with the 'D' and 4th blinking lights once the engine and transmission was at operating temperature, and this was after I changed the coolant valve due to leakage. The problem continued until I started to have gear shifts without any reason, so as a precaution i changed the transmission oil and filter. The lights continued to blink after the oil change. What I did eventually find thorough some troubleshooting was that the transmission selector switch was faulty. I replaced the switch
and have not had a problem since. I have driven several thousand kms since the switch replacement, Blinking lights gone, transmission operating normal.
Note you will need an OBD reader to clear the blinking lights once you have changed the switch.

[tonythetiger]

Originally Posted by snottas

Had the same problem with the 'D' and 4th blinking lights once the engine and transmission was at operating temperature, and this was after I changed the coolant valve due to leakage. The problem continued until I started to have gear shifts without any reason, so as a precaution i changed the transmission oil and filter. The lights continued to blink after the oil change. What I did eventually find thorough some troubleshooting was that the transmission selector switch was faulty. I replaced the switch
and have not had a problem since. I have driven several thousand kms since the switch replacement, Blinking lights gone, transmission operating normal.
Note you will need an OBD reader to clear the blinking lights once you have changed the switch.

the switch is 400 bucks...how did you determine it was a bad switch?
My tranny is shifting fine, BTW, but the fans run and it is acting as if it is slightly overheating. I am trying the coolant valve first, but honestly, I would be surprised if the coolant flowing makes this big of a difference. Still leaning towards faulty thermistor in internal harness as I heard the tranny ran dry for a short period of time with previous owner. (he had the tranny serviced and they forgot to put in fluid afterwards.

[snottas]

I was able to stop the lights from blinking (4th to D) and the irregular gear changes by minor adjustment of the cable at the switch or at the gear lever. This only temporarily fixed the problem as the next time I went to drive I had the same problem which again could be temporarily fixed by adjustment but with the same outcome until I changed the switch.
Note:- the original problem was the lights blinking which occurred each time I drove the vehicle.

[tonythetiger]

Originally Posted by snottas

I was able to stop the lights from blinking (4th to D) and the irregular gear changes by minor adjustment of the cable at the switch or at the gear lever. This only temporarily fixed the problem as the next time I went to drive I had the same problem which again could be temporarily fixed by adjustment but with the same outcome until I changed the switch.
Note:- the original problem was the lights blinking which occurred each time I drove the vehicle.

im pretty sure mine is related to heat...never does it cold, starts up after driving, happens quicker in hot weather and the fans run incessantly. I have a thermo to check the tranny temp ready for next time I drive the car and Im going to get into the engine bay this weekend to poke around, plus replace the coolant vacuum valve thingy. I expect my fix is the internal harness, but not sure yet.

[KuaiThunder]

Hi guys,

In stead of opening new thread I would just continue on this one. I have replaced my Gear Selection Switch about 5 years ago when first time I have the flashing “4” & “P” (Not “D”). Early last year I have a flashing “4” & “D” with code P0740 and I able to just clear the code and continue driving without issue until two days ago.

This time I have flashing “4” & “D” again and the code is 0035 “Multi-function Switch”. I believe this code is from TCU not ECU. Anyobe know what is “Multi-Function Switch” is? Or better yet have the part number for it?

Thx
2001 Boxster S Tip with 100K KM

[gazufo]

Originally Posted by snottas

Had the same problem with the 'D' and 4th blinking lights once the engine and transmission was at operating temperature, and this was after I changed the coolant valve due to leakage. The problem continued until I started to have gear shifts without any reason, so as a precaution i changed the transmission oil and filter. The lights continued to blink after the oil change. What I did eventually find thorough some troubleshooting was that the transmission selector switch was faulty. I replaced the switch
and have not had a problem since. I have driven several thousand kms since the switch replacement, Blinking lights gone, transmission operating normal.
Note you will need an OBD reader to clear the blinking lights once you have changed the switch.

hi and thanks for your info regarding the blinking lights etc. I have a 996 (98) and the same thing happened to me a couple of days ago. now I have a question, is it a matter of removing the centre console and simply swapping over the switch?

regards gaz

[Starter986]

Originally Posted by gazufo

hi and thanks for your info regarding the blinking lights etc. I have a 996 (98) and the same thing happened to me a couple of days ago. now I have a question, is it a matter of removing the centre console and simply swapping over the switch?

regards gaz

Do you own the repair manual?

[SC-986]

Originally Posted by Starter986

Do you own the repair manual?

Do you make these condescending comments to increase your post count?
Why not be a little more welcoming for the guys first post - or better yet don’t comment at all if you have nothing productive or informative to offer.

[tonythetiger]

Originally Posted by SC-986

Do you make these condescending comments to increase your post count?

Why not be a little more welcoming for the guys first post - or better yet don’t comment at all if you have nothing productive or informative to offer.

I don’t think this is condescending. Starter is pretty chill and always helpful. We all are.

I would look at the switch back by the tranny and make sure it’s well connected and clean. That could help and the manual can guide you.

Welcome


Sent from my iPhone using Tapatalk

[vrishnizzles]

Originally Posted by tonythetiger

I don’t think this is condescending. Starter is pretty chill and always helpful. We all are.

I would look at the switch back by the tranny and make sure it’s well connected and clean. That could help and the manual can guide you.

Welcome


Sent from my iPhone using Tapatalk

Hello (reviving this thread, maybe?),

New guy here! Recently rebuilt a 2003 Porsche Boxster Tiptronic (for my Dad as a retirement gift), tranny, engine, coolant, brakes, control arms, etc. The whole 9 yards. I have noticed after some time driving the car, the flashing lights blink (4 to Dri.) Now, it is important to note that the car has not been consistently driven for more than a thousand miles (could be due to that, but I'm not too sure.) Could this be linked to the aforementioned issues?

TYIA,

V