If you are getting a
“Fuel Cut off Unavailable”
or
“ABS Unavailable”
“See Handbook” message on the instrument panel, or if you are trying to read error codes off the ECU (aka PCM on some forums) using Multiecuscan or other scanning tool and are getting a message
“Connection Failed ELM327 ->ECU Connection Failed Canbus error. Check if interface is properly connected to the vehicle and correct vehicle/module selected” from Multiecuscan
or just not able to connect to your ECU with your diagnostic tool,
or Your Fiat 500 just will not start (dash lights up when you turn the key but no crank, no click, nothing) and that yellow car and padlock warning symbol is lit on the dash when you turn the key (usually indicating the car is not recognizing the key fob)
then please read on, because I am hoping by sharing my experience with you that it will save you hundreds of Euro, Pounds or Dollars! For me, the actual fix cost 8 euro, but I wasted 300 euro getting to the actual problem.
So, here goes. I bought our Fiat 500 1.2 Petrol 8V for my wife’s Christmas present back in Dec 2007 and eventually took delivery of it from new in Feb 2008. She already had a 1968 Fiat 500, and wanted a new one as they were only being launched then. Anyhow, nearly 14 years later, and 225km later the car is still going strong with only minor problems, well minor problems until recently! I’ve done all the maintenance on it myself since new.
A few weeks back I got a call from my wife, outside work, Fiat 500 won’t start. I went down, thinking maybe a battery issue, put a battery pack on it, but nothing. No Crank, no click, nothing, but all lights were on the dash, headlights, interior light, etc. all working. After a while fiddling with it without getting it going, decided to push start it, and it started!! That’s what threw me for a good bit of my diagnosis afterwards – it started on a push. Read on…
I checked the battery when we got home, no issue. So decided this was a starter motor issue. Also, before I took delivery of the new starter motor I push started the car a further two times for minor family emergencies (as my wife had our other car with her in work). Anyhow, third time I went to push start it, it would not start - all a bit strange. So, put new starting motor in. Delighted with myself as it was about a 30 minute job, so easy on these 1.2 500s (first time doing the starting motor so would be even quicker next time!) Hopped in the car, it would not start!! This was not a starter motor issue. And now I was getting Fuel cut off unavailable, ABS unavailable, see handbook messages on the instrument panel, and that dreaded car and padlock symbol down in the bottom right. So I got my Foxwell scanner tool out, it’s a decent enough one, and it could scan the Body Control Module (BCM), ABS module, etc. but it could not connect to the ECU. Now I was getting worried. So took out the laptop and tried scanning with Multiecuscan (if you want to maintain your Fiat you need this software and cable). I got this message
“Connection Failed ELM327 ->ECU Connection Failed Canbus error. Check if interface is properly connected to the vehicle and correct vehicle/module selected”
Now I was worried, had I somehow fried the ECU? Had I crossed wires somewhere along the way when disconnecting the battery to put the starter motor in, what had I done? I spent a lot of time at this stage checking things like wiring, the T09 relay that sits in the under bonnet fuse box which supplies power to the ECU, I took every fuse out both under bonnet and inside the car to check them, they were all fine. I read a lot on this and other forums but could not figure out what was wrong. So I decided, I need a new ECU. Now those of you that know their stuff will know you cannot just buy a second hand ECU, it won’t work. You need to programme it to recognize your BCM or you can buy a virginised plug and play ECU on ebay. So 200 euro later, I had a plug and play ECU winging its way to my house. Eventually the ECU arrived, 5 mins later, battery had been disconnected for a couple of days before this (important you don’t disconnect the battery straight after opening/driving the car – wait 15 mins to ensure car has fully shut down), four M10 nuts and the 2 block connectors later the new ECU was in – again so easy to do. Delighted but apprehensive, I jumped into the car and dash fully lit up like before, turned the key and nothing, not a crank, not a click, and there was the dreaded message “fuel cut off unavailable, ABS unavail………… “ AAAAgggggghhhhhh!
So, now, I started thinking was it a problem with the BCM, maybe it was not recognizing the key fob and hence it was not waking the ECU, which would explain why the scanning tools could not see the ECU. Spent a lot of time on Ebay looking at second hand BCMs, and second hand kits with BCM, ECU, Key fob, ignition barrel, door lock, petrol cap…….. Maybe I should just buy the lot and be done with it???
But before I made this next purchase, I decided to go a do a thorough check on what I had done, make sure I had not misplaced a wire, nicked a wire causing a short circuit, something.
I took the battery out, then the battery tray, checked the wiring to the fuse box, had a good root around and then I remember seeing on this forum, and this is the reason I am posting my lesson here, because some other people have mentioned it, and I dismissed it, but, I looked at the earth strap from the body to the Gearbox. It looked fine, there was what looked like a bit of rust on the gearbox side, nothing too bad, the structure looked good, but I gave it a light tug, and it started to separate, very easily actually, like pulling straw apart. It broke off completely on the gearbox end, with little effort. Could this be my problem, I was thinking could it be this simple, getting a little excited that I may have found the problem but afraid to believe it could be causing so much trouble. Surely a simple earth strap could not knock out the full ECU!! However, this strap, needed to be replaced as it was fully snapped now.
I already had a spare earth strap in the garage, don’t ask, I just have these things, I already had the battery and battery tray out, I disconnectedd the Clutch slave cylinder by removing the 2 x M10 bolts moved the slave cylinder out of the way, and replaced the earth strap. I hopped in the car and turned the key. I should probably say at this stage, that I have bought the spare earth strap in Halfords for something else I was going to do on a different car, it cost me 8 euro……
All that trouble, not starting, but starting on a push, ECU not being found by the scanners, all those error messages and warning symbols, it was all due to a really decent looking earth strap. Give yours a good tug soon, and see what happens!!!
I’ve spent a lot, and I mean a lot of hours researching Fiat 500 wiring, how the ECU & BCM modules work together, how to virginalise and ECU, how to programme keys, and much more, yet all I had to do was take the advice given out by one or two others, to check that earth strap. Hopefully this post will save one or two of you a lot of time too……
Enjoy your 500.
:bang:
“Fuel Cut off Unavailable”
or
“ABS Unavailable”
“See Handbook” message on the instrument panel, or if you are trying to read error codes off the ECU (aka PCM on some forums) using Multiecuscan or other scanning tool and are getting a message
“Connection Failed ELM327 ->ECU Connection Failed Canbus error. Check if interface is properly connected to the vehicle and correct vehicle/module selected” from Multiecuscan
or just not able to connect to your ECU with your diagnostic tool,
or Your Fiat 500 just will not start (dash lights up when you turn the key but no crank, no click, nothing) and that yellow car and padlock warning symbol is lit on the dash when you turn the key (usually indicating the car is not recognizing the key fob)
then please read on, because I am hoping by sharing my experience with you that it will save you hundreds of Euro, Pounds or Dollars! For me, the actual fix cost 8 euro, but I wasted 300 euro getting to the actual problem.
So, here goes. I bought our Fiat 500 1.2 Petrol 8V for my wife’s Christmas present back in Dec 2007 and eventually took delivery of it from new in Feb 2008. She already had a 1968 Fiat 500, and wanted a new one as they were only being launched then. Anyhow, nearly 14 years later, and 225km later the car is still going strong with only minor problems, well minor problems until recently! I’ve done all the maintenance on it myself since new.
A few weeks back I got a call from my wife, outside work, Fiat 500 won’t start. I went down, thinking maybe a battery issue, put a battery pack on it, but nothing. No Crank, no click, nothing, but all lights were on the dash, headlights, interior light, etc. all working. After a while fiddling with it without getting it going, decided to push start it, and it started!! That’s what threw me for a good bit of my diagnosis afterwards – it started on a push. Read on…
I checked the battery when we got home, no issue. So decided this was a starter motor issue. Also, before I took delivery of the new starter motor I push started the car a further two times for minor family emergencies (as my wife had our other car with her in work). Anyhow, third time I went to push start it, it would not start - all a bit strange. So, put new starting motor in. Delighted with myself as it was about a 30 minute job, so easy on these 1.2 500s (first time doing the starting motor so would be even quicker next time!) Hopped in the car, it would not start!! This was not a starter motor issue. And now I was getting Fuel cut off unavailable, ABS unavailable, see handbook messages on the instrument panel, and that dreaded car and padlock symbol down in the bottom right. So I got my Foxwell scanner tool out, it’s a decent enough one, and it could scan the Body Control Module (BCM), ABS module, etc. but it could not connect to the ECU. Now I was getting worried. So took out the laptop and tried scanning with Multiecuscan (if you want to maintain your Fiat you need this software and cable). I got this message
“Connection Failed ELM327 ->ECU Connection Failed Canbus error. Check if interface is properly connected to the vehicle and correct vehicle/module selected”
Now I was worried, had I somehow fried the ECU? Had I crossed wires somewhere along the way when disconnecting the battery to put the starter motor in, what had I done? I spent a lot of time at this stage checking things like wiring, the T09 relay that sits in the under bonnet fuse box which supplies power to the ECU, I took every fuse out both under bonnet and inside the car to check them, they were all fine. I read a lot on this and other forums but could not figure out what was wrong. So I decided, I need a new ECU. Now those of you that know their stuff will know you cannot just buy a second hand ECU, it won’t work. You need to programme it to recognize your BCM or you can buy a virginised plug and play ECU on ebay. So 200 euro later, I had a plug and play ECU winging its way to my house. Eventually the ECU arrived, 5 mins later, battery had been disconnected for a couple of days before this (important you don’t disconnect the battery straight after opening/driving the car – wait 15 mins to ensure car has fully shut down), four M10 nuts and the 2 block connectors later the new ECU was in – again so easy to do. Delighted but apprehensive, I jumped into the car and dash fully lit up like before, turned the key and nothing, not a crank, not a click, and there was the dreaded message “fuel cut off unavailable, ABS unavail………… “ AAAAgggggghhhhhh!
So, now, I started thinking was it a problem with the BCM, maybe it was not recognizing the key fob and hence it was not waking the ECU, which would explain why the scanning tools could not see the ECU. Spent a lot of time on Ebay looking at second hand BCMs, and second hand kits with BCM, ECU, Key fob, ignition barrel, door lock, petrol cap…….. Maybe I should just buy the lot and be done with it???
But before I made this next purchase, I decided to go a do a thorough check on what I had done, make sure I had not misplaced a wire, nicked a wire causing a short circuit, something.
I took the battery out, then the battery tray, checked the wiring to the fuse box, had a good root around and then I remember seeing on this forum, and this is the reason I am posting my lesson here, because some other people have mentioned it, and I dismissed it, but, I looked at the earth strap from the body to the Gearbox. It looked fine, there was what looked like a bit of rust on the gearbox side, nothing too bad, the structure looked good, but I gave it a light tug, and it started to separate, very easily actually, like pulling straw apart. It broke off completely on the gearbox end, with little effort. Could this be my problem, I was thinking could it be this simple, getting a little excited that I may have found the problem but afraid to believe it could be causing so much trouble. Surely a simple earth strap could not knock out the full ECU!! However, this strap, needed to be replaced as it was fully snapped now.
I already had a spare earth strap in the garage, don’t ask, I just have these things, I already had the battery and battery tray out, I disconnectedd the Clutch slave cylinder by removing the 2 x M10 bolts moved the slave cylinder out of the way, and replaced the earth strap. I hopped in the car and turned the key. I should probably say at this stage, that I have bought the spare earth strap in Halfords for something else I was going to do on a different car, it cost me 8 euro……
All that trouble, not starting, but starting on a push, ECU not being found by the scanners, all those error messages and warning symbols, it was all due to a really decent looking earth strap. Give yours a good tug soon, and see what happens!!!
I’ve spent a lot, and I mean a lot of hours researching Fiat 500 wiring, how the ECU & BCM modules work together, how to virginalise and ECU, how to programme keys, and much more, yet all I had to do was take the advice given out by one or two others, to check that earth strap. Hopefully this post will save one or two of you a lot of time too……
Enjoy your 500.
:bang:
