1.2 tdi 3l gearbox problems

[Rudolf]

Transmission problems. Any advice is welcomed! 

Hey guys, VW Lupo 1.2tdi 3L 2001. owner here.

I have run into some transmission problems. I was overtaking a car on the road and the Lupo performed kick down from gear 4 to gear 3, and seamed ir chuld not find the gear. The gears in the panel flashed between each other and the car went into SAFETY MODE?
I can turn on the engine but the accelerator pedal is unresponsive. And the lights by gears stick are flashing "+" "-" "D" "N" both when in tiptronic or automatic.
When turning ignition but not starting engine, switching gears in tiptronic mode shows in dashboard but i can hear that the car is not switching gears. 

My friend pulled me home from midle of road.

Assessments:

VCDS shows:
01605 Potentiometer 2 for gear recognition (G240)

Basic setting stops after the 28 step shifts and writes RTFM! with same error
(First time I have done basic settings for the car) 

Checked wiering from potentiometer 2 to gerbox ECU with beeping tester, all 3 wires test oky.

Gear selector rod has small movment in top ball head 

Prior to incident Pressure Accumulator made 6 gear changes before starting the pump. Oil level is good. 

History:
Before this incident, the car already had a faulty 5 gear, first 4 gears worked perfectly fine but when switched into 5th, the car in couple secs went into safety mode. Afrer switching ignition off and on chuld use first 4 gear perfectly fine again but not the 5th.

Mechanics in my area doesn't understand the 1.2 3l transmission, so i only used the first 4 gears but now the car doesn't work so I will try to figure the problem out myself.

Any advice on what else shuld i test or what chuld be the problem?

Faulty top potentiometer is the obvious answer but do they break and how can I test it befor paying the €€€

Whuld switching potentiometer 1 and 2 with places resort in the error code changing from g240 to g239?

[mk2]

@RAB knows the answer.

RAB this is asked a lot. Any chance you could be a hero and write a quick "how to" for everyone? I never ever hear of any 3L engine issues, but gearbox questions are always coming up. Usually loss of gear selection or just plain limp mode.

[RAB]

Already answered: https://www.a2oc.net/community/index.php?threads/1-2tdi-3l-transmission-problems.45281/

A "How To" on what? There are many causes of gearbox problems, a major one being lack of proactive maintenance! For this one, it's probably a sensor pot failure which is not very common.

RAB