paulcrema
New member
I have a 2016 fiat 500x . The warning light : service keyless entry system has activated. Does anyone have experience with this warning? What service is required? What is the problem or fix? Any input would be appreciated.
Technical Warning light : service keyless entry
- Thread starter paulcrema
- Start date
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Technical Warning light : service keyless entry
Well today I now have this issue myself.
I was hoping it would never come my way but alas I guess my luck just ran out.
Not look yet or plugged in the diagnostics yet.
I think I'll just go straight to the RFH module first and take it from there.
I was hoping it would never come my way but alas I guess my luck just ran out.
Not look yet or plugged in the diagnostics yet.
I think I'll just go straight to the RFH module first and take it from there.
A small update.
I decided to connect diagnostics first and found RFH Error.
MaxiECU Had: B1035-01 : Button Pressed - General Electric Failure
MultiECUScan Had: B1035-01 : External handle input for Passive Entry - General Electrical Failure
Interestingly the Fiat eLearn diagnostics have: Button Pressed - General Electrical Failure B1035-01
So we have two different descriptions of the problem. Now the door handle sensor connect to the RFH as does the Start/Stop button.
I also found that the error once cleared reappears when the Start/Stop button is pressed.
I gained access to the RFH module and noticed small drops of water on one of the seams facing the rear. The module also slopes backward to rear and right end down.
The cables themselves felt dry.
I need to inspect in greater detail tomorrow (weather permitting) before removing the module and connectors. The purpose of doing this is to see where the water is coming in. Based on what I have seen so far I think it may be from where the boot seal goes round the top of the hatch back/roof line to wrap down the C post upper wing lip. Right in that top left corner the roof and upper C post join with basically on overlap this creating a ridge. Also as it is on the bend then the usual rubber seal profile will probably be bending/bulging a little.
If what I suspect is the water ingress method is correct then I think the fix will be fairly simple.
1) create a shield / shroud over the top of the RFH module
2) lift the tailgate hate rubber seal, clean any rubbish out, reform the bend area and then put back with loads of Waxoil
Fingers crossed the module / connectors when cleaned will be be back up and running OK.
Will keep you all posted.
Nick
I decided to connect diagnostics first and found RFH Error.
MaxiECU Had: B1035-01 : Button Pressed - General Electric Failure
MultiECUScan Had: B1035-01 : External handle input for Passive Entry - General Electrical Failure
Interestingly the Fiat eLearn diagnostics have: Button Pressed - General Electrical Failure B1035-01
So we have two different descriptions of the problem. Now the door handle sensor connect to the RFH as does the Start/Stop button.
I also found that the error once cleared reappears when the Start/Stop button is pressed.
I gained access to the RFH module and noticed small drops of water on one of the seams facing the rear. The module also slopes backward to rear and right end down.
The cables themselves felt dry.
I need to inspect in greater detail tomorrow (weather permitting) before removing the module and connectors. The purpose of doing this is to see where the water is coming in. Based on what I have seen so far I think it may be from where the boot seal goes round the top of the hatch back/roof line to wrap down the C post upper wing lip. Right in that top left corner the roof and upper C post join with basically on overlap this creating a ridge. Also as it is on the bend then the usual rubber seal profile will probably be bending/bulging a little.
If what I suspect is the water ingress method is correct then I think the fix will be fairly simple.
1) create a shield / shroud over the top of the RFH module
2) lift the tailgate hate rubber seal, clean any rubbish out, reform the bend area and then put back with loads of Waxoil
Fingers crossed the module / connectors when cleaned will be be back up and running OK.
Will keep you all posted.
Nick
Fixed! and hopefully for a long time to come.
Firstly I found some light film of water in the lower wing cavity. We have had a reasonable amount of rain over the last few days so any water that is getting in is minimal. That said continued damp on connectors / electronics is not good.
I could not really find as such by feel where the water was coming in. That said when I lifted the tail gate rubber it was quite damp and droplets of water on the inner channel. Pretty sure the water is getting in on the top corners where the seal bends around and downwards over the ridged seam where the upper C panel meets the roofline. I've pulled and cleaned both corners and down to lights. Refitted with lots of waxoil also ensuring the really gave the top corner ridge seam most attention.
Now for the RFH module (RFHM).
The best way to get this out is to removed the carrier frame from its three post fixings. One up on the inner wing to the left, one down on the wheel arch to the right, and one further up on the top of the wheel arch.
Now one can unplug the two connectors (slide the grey tab backwards) and fully remove the frame and dismount the RFHM.
On inspection I was expecting the larger right side connector to be troubled / corroded but actually it was left side one. Only mild stuff and nothing on the circuit board (unlike some previous post pictures.
Looking at the wiring runs and "angles of dangles" I decide to dispense with the carrier frame and mount the module twisted 90 degrees clockwise using just the one mounting. Also put 5mm neoprene mat underneath the module secure with tie wrap.
With the module in this position the larger connector and cable are facing down. The upper connector cable has a nice cable drip loop.
Lastly I covered the whole assembly and cables with a thick polythene sheets. This slide up behind the seat belt reel and goes over the module and wires down into the inner wing. The sheet is secured using the un-used frame mounting studs.
I'm hopeful that this fix remains permanent even if water finds it's way in again.
Firstly I found some light film of water in the lower wing cavity. We have had a reasonable amount of rain over the last few days so any water that is getting in is minimal. That said continued damp on connectors / electronics is not good.
I could not really find as such by feel where the water was coming in. That said when I lifted the tail gate rubber it was quite damp and droplets of water on the inner channel. Pretty sure the water is getting in on the top corners where the seal bends around and downwards over the ridged seam where the upper C panel meets the roofline. I've pulled and cleaned both corners and down to lights. Refitted with lots of waxoil also ensuring the really gave the top corner ridge seam most attention.
Now for the RFH module (RFHM).
The best way to get this out is to removed the carrier frame from its three post fixings. One up on the inner wing to the left, one down on the wheel arch to the right, and one further up on the top of the wheel arch.
Now one can unplug the two connectors (slide the grey tab backwards) and fully remove the frame and dismount the RFHM.
On inspection I was expecting the larger right side connector to be troubled / corroded but actually it was left side one. Only mild stuff and nothing on the circuit board (unlike some previous post pictures.
Looking at the wiring runs and "angles of dangles" I decide to dispense with the carrier frame and mount the module twisted 90 degrees clockwise using just the one mounting. Also put 5mm neoprene mat underneath the module secure with tie wrap.
With the module in this position the larger connector and cable are facing down. The upper connector cable has a nice cable drip loop.
Lastly I covered the whole assembly and cables with a thick polythene sheets. This slide up behind the seat belt reel and goes over the module and wires down into the inner wing. The sheet is secured using the un-used frame mounting studs.
I'm hopeful that this fix remains permanent even if water finds it's way in again.
damomca
Member
I posted in March about the check keyless entry error I was getting and then the car stopped recognising both keys.
I located the RFHM unit from the boot and could see a little corrosion on the connector and on the PCB itself.
I took the RFHM unit to a local auto electrician who said it was quite badly damaged, but he re-soldered some of the connectors and gave it back to me to try, with no warranty.
I put it back on the car and the keys were recognised again and I could use them, but was still getting the check keyless entry error.
I could see from looking at the RFHM installation that it could allow water to follow down wires into it. I re-routed the wire into it a little so it created a loop back up into the RFHM, so water in theory couldn't track back up into it.
So, I'm still getting the check keyless entry error, but the keys are still recognised and work, so I haven't bothered getting it resolved any further. I guess I'm nervous or paying £800 getting a new module just for it to get water damaged again.
I located the RFHM unit from the boot and could see a little corrosion on the connector and on the PCB itself.
I took the RFHM unit to a local auto electrician who said it was quite badly damaged, but he re-soldered some of the connectors and gave it back to me to try, with no warranty.
I put it back on the car and the keys were recognised again and I could use them, but was still getting the check keyless entry error.
I could see from looking at the RFHM installation that it could allow water to follow down wires into it. I re-routed the wire into it a little so it created a loop back up into the RFHM, so water in theory couldn't track back up into it.
So, I'm still getting the check keyless entry error, but the keys are still recognised and work, so I haven't bothered getting it resolved any further. I guess I'm nervous or paying £800 getting a new module just for it to get water damaged again.
Last edited:
You need to tend to the actual cable end connectors as well. Cleaning the circuit board and circuit board connectors is OK but the cable end connectors will be corroded / tarnished a as well.
I thought in my post that I mentioned in detail how I cleaned and lubricated the circuit board connectors and the cable end connectors. Anyway here is the info again:
12/09/25 - Fault - "Check Keyless Entry System" error on dashboard.
0032,298
MaxiECU Had: B1035-01 : Button Pressed - General Electric Failure
MultiECUScan Had: B1035-01 : External handle input for Passive Entry - General Electrical Failure
Fiat 500X eLearn diagnostics has: Button Pressed - General Electrical Failure B1035-01
o Stripped down boot rear end cover and LHS boot trip and carpet wall
o Notice water on the module case
o Removed RFHM complete with carrier frame
o Removed connectors - slide grey tab backwards and depress latch head/button
o Removed module from frame, opened module case and removed circuit board
o Smaller LHS connector has mild corrosion on lower end pins
o Larger RHS connector looks dry and clean
o Used alcohol and small wire brush to clean pins
o Repeated with switch cleaner and lubricator
o Gently scrapped all pin side with small file
o Re-lubricated with switch cleaner and lubricator
o For both connectors applied alcohol and blew through with compressed air
o For both connectors applied switch cleaner and lubricator
o For both connectors inserted/removed flat electrical matching connector pin several times
o For both connectors applied switch cleaner and lubricator again
o For both connectors connected / removed from RHFM module
o Checked with MaxiECU that fault was fixed
o Replace RFRM *without* frame and rotated through 90 degrees using only lower mounting stud but
with neoprene pad tie wrapped to underside of the RFHM
o With the module in this position the larger connector and cable are facing down. The upper
connector cable has a nice cable drip loop
o Covered the whole assembly and cables with a thick polythene sheets. These slide up behind the
seat belt reel and goes over the module and wires down into the inner wing. The sheet are secured
using the un-used frame mounting studs.
o Test again
o Put all trim back
valerioFiat500X
New member
Hi,
Thanks for all the information. Yesterday, after the heavy rain in Kent, my car went completely crazy. It started with a “keyless entry” warning, then random alerts about the airbag, start & stop system, and other things. The engine stopped running, but the electronics kept switching on by themselves.
I decided to lock the car and go home, planning to check it again this morning. When I returned, the battery was completely flat (I replaced it just a month ago, so it’s almost new). All the doors were locked, and the handbrake was engaged. I had to call a tow truck to bring it home, and the driver somehow managed to release the handbrake.
This afternoon, I opened the boot from the inside and checked the RFHM, it was totally wet, especially around the smaller plug. The circuit board was damp but not moldy, and actually in better shape than some of the pictures others have shared.
I’m now recharging the battery and will try to reassemble everything tomorrow. I was wondering if you could share some pictures of how you repositioned or reinstalled everything, so I can try to replicate your setup.
Many thanks,
valerioFiat500X
New member
Hi everyone,
As mentioned before, I’ve been experiencing the same issue that many of you described. I’ve already tried all the suggested fixes - cleaned and dried the module, checked and dried all connectors and plugs - but the car still shows the same error and the engine won’t start.
Is there anything else I should try? I’m wondering if the system might need some kind of reset. Any advice would be really appreciated.
Thanks in advance,
As mentioned before, I’ve been experiencing the same issue that many of you described. I’ve already tried all the suggested fixes - cleaned and dried the module, checked and dried all connectors and plugs - but the car still shows the same error and the engine won’t start.
Is there anything else I should try? I’m wondering if the system might need some kind of reset. Any advice would be really appreciated.
Thanks in advance,
valerioFiat500X
New member
Hi, I'm having the same issue but after claning the module the car is still showing the same error. Did you do anything else after cleaning the module? thanksI've got the same issue on 500X CROSS, look what I funded in the boot , I've cleaned the pins and the issue has goneit's worth to try!
I'm sorry but I did not take any pictures other than those to my mind/memory/view and textually detailed in my post.
The RFHM getting wet over a period of time seems to be the cause of issues for many people. Getting it clean and dry along with all the connector contacts on the module circuit board pins and the cable connector sockets seems to be crucial.
Before worrying about re-orientating / positioning and protecting the module in the future you need to first get it all back working again.
Others have taken pictures of the module circuit board etc. showing obvious tarnishing (white corrosive residue stains) of the board and solder joints. You need to check that all is clean and there are no breaks in tracks or loose solder joints. The cable connectors are more difficult to deal with. Good flooding with alcohol and multiple connecting and disconnecting the connectors to the circuit board to effect insertion pin to socket self cleaning is ideally required. Close inspection of every contact (male/female) ideally with a magnifying glass should be done, also on the cable connector examining the back cable entrance into the connector shell itself.
Sadly we are talking some 20 to 30 connector contacts and any one could, if defective, cause issues.
As for a system reset I did all my work with the battery negative terminal (simple quick release post on ground strap terminal on the 500X). Suggest you disconnect this negative lead and let the system rest for say 30 minutes so all the cars modules and body computer can gracefully die. Re-connect and try again.
The RFHM getting wet over a period of time seems to be the cause of issues for many people. Getting it clean and dry along with all the connector contacts on the module circuit board pins and the cable connector sockets seems to be crucial.
Before worrying about re-orientating / positioning and protecting the module in the future you need to first get it all back working again.
Others have taken pictures of the module circuit board etc. showing obvious tarnishing (white corrosive residue stains) of the board and solder joints. You need to check that all is clean and there are no breaks in tracks or loose solder joints. The cable connectors are more difficult to deal with. Good flooding with alcohol and multiple connecting and disconnecting the connectors to the circuit board to effect insertion pin to socket self cleaning is ideally required. Close inspection of every contact (male/female) ideally with a magnifying glass should be done, also on the cable connector examining the back cable entrance into the connector shell itself.
Sadly we are talking some 20 to 30 connector contacts and any one could, if defective, cause issues.
As for a system reset I did all my work with the battery negative terminal (simple quick release post on ground strap terminal on the 500X). Suggest you disconnect this negative lead and let the system rest for say 30 minutes so all the cars modules and body computer can gracefully die. Re-connect and try again.
valerioFiat500X
New member
Thanks a lot for the advice!
I’ll give it another thorough clean and see how it goes. The module itself seems fine to be honest, but I might try cleaning the plug more thoroughly.
As for the battery, it’s been disconnected for two days — since this issue started, the system drained it completely overnight (not sure why, but it seems to keep running even with the doors closed). I’m keeping it disconnected for now, but I’ll reconnect it and test again.
Thanks!
