Can anyone help me. For some reason my park assist has stopped working. Nothing shows on screen, no parking sensors and no reversing lights. Fuse ok so I’m thinking maybe it’s a switch on the reverse. 

2017 Fabia SE L 

I'd try a reboot on the infotainment unit first, I had this happen once to me. Push in the power/volume knob for 10 seconds, you'll see it restart. See if that makes it work again. It doesn't wipe any settings or anything.

It didn't work

If there's no reverse lights its not the infotainment system. There will be a switch somewhere for reverse but I don't know where. Could be that switch that is the problem, or the wiring to it.

 

I would expect the system looks quite different between DSG and manual. I'm not at all familiar with the layout on Fabia 3 but I'd expect for the DSG the gearbox computer (probably what's called the mechatronic) sends a CAN or FR message, and then the BCM (maybe BCM2 if there are two) reads the signal and puts on the lights. On a manual, some other computer will read the switch and put the information on CAN. In all cases if the switch isn't working, none of the systems will know the car is in reverse and none of the assosciated system will work.

 

EDIT: looking at photos on ebay, there is a separate reverse switch (or at least what lloks like one) by the selector mechanism.

Edited 28 January, 20206 yr by lowedb

Thanks. I thought it might be the switch. I’ll have a look on eBay 

That sounds like semi blind firing of the parts cannon, you must be feeling lucky, I have a feeling that DSG boxes do not have simple external mounted switches, even 5 and 6 speed manual gearboxes have an switch/indicator for every gear, so all a bit trickier than it used to be.

On 28/01/2020 at 21:18, rum4mo said:

... even 5 and 6 speed manual gearboxes have an switch/indicator for every gear, so all a bit trickier than it used to be.

Are you sure? If you are thinking that because of the gear shift indicator in the instrument pack, then it's not done with a switch. Notice that the indication goes out when you press the clutch. When the clutch isn't pressed it can use the relative speed of the input and output shafts to work out what gear it is in. And no there aren't neccesarily sensors for that either, as the input shaft turns at the same speed as the engine (so long as the clutch is engaged), the output shaft turns at a speed fixed by the speed of the wheels and the ratio of the diff. My 12 plate Superb 6 speed certainly did this because selecting N and releasing the clutch while moving would flash up different gears as I slowed and the speeds briefly matched the window.

 

You are probably right about DSGs though. It's almost certainly the ECU (mechatronic) that sends a CAN (or FR) signal.

Edited 30 January, 20206 yr by lowedb

13 minutes ago, lowedb said:

Are you sure? If you are thinking that because of the gear shift indicator in the instrument pack, then it's not done with a switch. Notice that the indication goes out when you press the clutch. When the clutch isn't pressed it can use the relative speed of the input and output shafts to work out what gear it is in. And no there aren't neccesarily sensors for that either, as the input shaft turns at the same speed as the engine, the output shaft turns at a speed fixed by the speed of the wheels and the ratio of the diff. My 12 plate Superb 6 speed certainly did this because selecting N and releasing the clutch while moving would flash up different gears as I slowed and the speeds briefly matched the window.

 

That was an assumption and based on some parts I noticed in the gearbox parts listing, so maybe 1+1 does not necessarily make 11!

 

So, something else to try out on our cars!

I’ve bought a new reverse switch from Eurocarparts and gonna fit it at the weekend. I hope that works.

On 30/01/2020 at 18:46, lowedb said:

Are you sure? If you are thinking that because of the gear shift indicator in the instrument pack, then it's not done with a switch. Notice that the indication goes out when you press the clutch. When the clutch isn't pressed it can use the relative speed of the input and output shafts to work out what gear it is in. And no there aren't neccesarily sensors for that either, as the input shaft turns at the same speed as the engine (so long as the clutch is engaged), the output shaft turns at a speed fixed by the speed of the wheels and the ratio of the diff. My 12 plate Superb 6 speed certainly did this because selecting N and releasing the clutch while moving would flash up different gears as I slowed and the speeds briefly matched the window.

 

You are probably right about DSGs though. It's almost certainly the ECU (mechatronic) that sends a CAN (or FR) signal.

 

Well, I've tried knocking my wife's August 2015 VW Polo out of 4th gear then taking my foot of the pedal, and dropped the revs to simulate changing up to 5th gear while moving at 40MPH, no gears indicated, tried increasing the revs to simulate changing down a gear to 3rd, no gear indicated. So that theory was not correct for the 6C VW Polo 6MT!

Sorted. It wasn't the gearbox switch. It was the wires going to the switch. It's a common fault. The wires only just reach. VW do a repair kit with extended wires. Took the switch back to Euro car parts £23.49 refund, replacement VW part £15

Good outcome, easy when you discover this sort of thing.

 

I bought a front wheel drive Ford Escort 1.6Ghia new years ago, it came with a very simple "reversing switch extension cable" - I didn't like the look of that one bit, a large plug, short length of wire and a large socket - I removed that bit, found a better way to route that cable and that sorted things for me! 

 

Maybe I need to check the reverse switch wiring on my wife's 2015 VW Polo 6MT!

 

Edit:- was that car not still within warranty? Though maybe you didn't want to be messing about with dealerships.

Edited 5 February, 20206 yr by rum4mo

If you have the part number, maybe pop it in here? Might help someone else down the line 😎

Reverse light repair loom

Part numbers...

CONNECTOR   1J0 973 702

WIRES               000 979 038 E

I bought it off Ebay

On 05/02/2020 at 06:05, Stuart8 said:

Sorted. It wasn't the gearbox switch. It was the wires going to the switch. It's a common fault. The wires only just reach. VW do a repair kit with extended wires. Took the switch back to Euro car parts £23.49 refund, replacement VW part £15

 

Good news in a way. Had a similar issue with a 1.9tdi roomy where the alternator charge warning wire wore through on a bracket.

Hi, @Stuart8 can you tell me where the switch is located please, can it be accessed with a ramp?