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

[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

[tonythetiger]

Originally Posted by vrishnizzles

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

had this on a 2002 986 S...problem was resolved by replacing the transmission harness. this harness was sourced for about 150 dollars and was pretty simple to swap. A little tedious, but what isnt? (gotta look for the right one and not get it from the dealership) and its important to note that the car was NOT going into limp mode, just sending the flashing lights. Also, Make sure the tranny isnt getting hot because the coolant system isn't working. You can use an infrared thermometer for this.
I surmise that the thermistor on the original harness was cooked.
Hope this helps.