[Bob.W]

Hi All,

Recently I came across a terrific buy on a brand new official Hyundai Towbar and wiring kit for the PD. The part numbers are G3A35APH00 + G3A04APH00 (apparently these were superceded by the current part numbers but confirmed by Hyundai Australia as correct for my vehicle (PD MY18)).  Bought from a dealership in Orange.

Haha not sure really why I bought it but is handy for the occasional Bunnings courtesy trailer load of large items or if I need to pull the skin off a custard!  700kg unbraked towing limit.  :-/

Install all seemed to go fine - but upon starting the car for the first time the display shows a CHECK SYSTEM error message. And the usual Rear Park Assist (beeping and visual on display of how close objects at rear are) didn't come up.

I assumed I'd inadvertantly not connected up some of the multiple rear sensors on the bumper fascia.  But I know I was extra careful to double check this, through a good design by Hyundai it's impossible to connect things incorrectly (as different plugs for different types of connections back there) and I just checked under the car with a light and mirror and can see the two rear centre sensors are definitely connected properly.

Making it more confusing the rear corner sensors are working correctly when driving (blindspot warning goes off as normal and cross traffic rear alert).  But just the rear park assist doesn't?

Making this more confusing the Hyundai Install Guide has odd information as at Step 24 it states,"When trailer test board is connected Rear Park Assist will be disabled and a warning will show on the dashboard. This will disappear when trailer test board is disconnected."   

Now I have NOT used a test board yet (as do not have one nor felt need to test, was 99% sure it was wired correctly and also was going to check when via a neighrbours trailer when I needed to use it rather than purchase a $25 tester I'd use once and never again) but with nothing connected to rear connection this error & disabling still occurs.  So why am I getting the Park Assist off and the error message without any tester connected (as the instructions state)....?

Thanks in advance for any thoughts or feedback .
BoB

[The Gonz]

I replied to a similar problem here:

Towing hook problem with rear radar

My suggestion of subtle selective blocking of the towbar's line of sight to the ultrasonic sensors was proven to work.

If you're interested in a custom 3D printed solution as mentioned in the above thread, let me know.

[The Gonz]

OK, so here's a softer design I knocked up just now, kinder to your carwash sponge.
A couple of these on the sides of your rear facing sensors adjacent to your towbar and you'll be all sorted.

[Bob.W]

The Gonz,

Much thanks for your reply - though from reading the linked post I don't think thats the issue for me. 

From what i read the chap from Finland had his sensors going off when he had a towhook (perhaps this what they refer to a towball as) whenever it was fitted and he selected reverse.  I can see how this could occur and the solution.

But my problem is different - the towball & tongue mount is actually not fitted at all - as I'm not using it, it's in the boot and just the towbar is fitted. So it's not that the rear assist sensors are going off detecting something, rather they're no longer sensing anything at all.

Determining why they're doing this - as they very much seem properly connected is my conundrum.

I have written and asked Hyundai Australia but they're usually incredibly crap at responding hence I had a lot more confidence in the good folks here - so I don't think your solution would assist - but it's incredibly innovative, well done.

[The Gonz]

Oops, sorry, Bob. It seems my excitement got ahead of my comprehension. It’s certainly odd behaviour. I guess you have warranty cover on both the car and the tow bar kit so there’s no escaping Hyundai’s responsibility.

I can only add that the old chestnut of disconnecting the battery for 30 minutes might help.

[Pnut]

Perhaps they have tapped into the feed to the sensors to power the trailer, or maybe have tapped into something causing feedback into the light system or even trans ecu depending on what they have done. They may have disconnected something?

[Bob.W]

Oops, sorry, Bob. It seems my excitement got ahead of my comprehension. It’s certainly odd behaviour. I guess you have warranty cover on both the car and the tow bar kit so there’s no escaping Hyundai’s responsibility.

I can only add that the old chestnut of disconnecting the battery for 30 minutes might help.

No harm done - great solution to that other issue though - very impressive.  Hmmm I dunno about the battery disconnect - perhaps I will try this weekend, but I already had the battery disconnected when doing all the install.  Anyway appreciate the suggestion.

Perhaps they have tapped into the feed to the sensors to power the trailer, or maybe have tapped into something causing feedback into the light system or even trans ecu depending on what they have done. They may have disconnected something?

Yes, this is my thoughts EXACTLY though it'd be incredibly stupid of them and also downright rude given they've at no time alluded to this occurring or being a potential issue in the instructions.  So I tend to think it's unlikely as there'd atleast be a 'BE AWARE' type caution there - especially given as I alluded that step 24 states that while a tester is connected the RPA will not work.

It doesn't seem logical to me that you MUST test the connection using a trailer plug tester or somehow the system isn't cleared and this error shows?   That seems too odd to make sense.

ANyway Hyundai Australia claims 3 business days for a response which in my experience is complete and utter bollocks......but worst case perhaps they have some type of insight.

[Bob.W]

Well heard back from Hyundai - they simply gave a generic "Go to the dealer" response _ I will press them on simply asking IF having the towbar fitted means the RPA won't work but again they've shown me that they are completely useless even when it comes to asnwering very generic basic questions.

I took the fascia off the rear bumper and confirmed that the wiring and plugs are all properly connected. Not really sure what more I can check, the only thing I can think of is to buy or borrow a trailer plug tester as perhaps that somehow is involved in the issue as the instructions do say to test the wiring - but again I don't think it'd disable a park of the car unless you simply tested the trailer wiring, seems very odd way to do things.

Kind of out of ideas.

PS. After googling - it seems there is a known issue for the Reverse Park Assist when the towbar is fitted to vehicles that have it - apparently there's two different wiring looms/kits one for the one with RPA and one for the one without.  I can't find any more info on it than that at this stage. PITA

[Bob.W]

Ok finally got issue sorted - beforehand I must say SHAME on Hyundai Australia for being more useless than tits on a bull.  Making any effort to get assistance from them in the years I've had this car has been a complete waste of time.  They NEVER show any effort whatsoever and only seem interested in funneling owners to their dealer network to fleece (sorry but my experience with Hyundai dealers is they're shoddy as can be but charge like they're top of market!).     Hyundai made no effort to assist - even replying back with blank replies to my queries.  Honestly they're so crap it's beyond words.

Through googling and some assistance from the original seller that put me on the path to finding what to search for I found the issue.

When installing I noticed that the harness came with 9 wires on it - yet the standard flat pin socket only has space for 7.  When I tried to find diagrams of this to see where these two wires went (one pink and the other purple) I had no luck at all.  So when I installed at first I just taped these down back on the cable run.

The original seller (a Ford dealership in Orange who were excellent! - advised that their install team said it was likely a wire not in the right place - but they had no more info.  So found that the pink and lilac wires were auxiliary cables often used for reversing sensors.  Sounded like a lead!

So in looking into this I found others who had the same issue. Turns out they're wired into either end of the socket (I don't know how I missed the inputs for these but they're very small).  They work with the magnet in the lid of the socket to tell when there's a trailer plugged in and deactivate the sensors.

Pulled off the socket, rewired it. Tested all working.  Anyway hope this assists someone, just know that Hyundai's Customer Care is ironically named and will not assist you in any meaningful way.

[Pnut]

Interesting! Thanks for putting the results up!

[The Gonz]

Nice work, Bob. This will save someone else no end of grief in future, I'm sure.
If you have a diagram or photograph that illustrates the wiring going to the right place, it would make a fine piece of forum knowledge for the members.

[Ratmick]

I have a factory fitted manual PD.4 with a tow-bar fitted by Essendon Hyundai from new if anyone wants factory wiring details in the future.

...I agree with the sentiments on Hyundai Australia (and Essendon Hyundai) as I have requested assistance with the abysmal LED headlights and the they have flat-out refused to engage except tell me anything I do will invalidate my warranty.

...took three goes to fit the tow-bar correctly too