Hi all,
I may have a the beginnings of low cost fix route for some power steering failures that relate to the motor.
There are a lot of threads on this topic and I have read the EPAS stickied guide before posting.
Here's my story - sorry for the long post:
About a week ago, I turned over the ignition to start my X-reg 1242 Mia. I didn't crank it for long enough to start it, so I turned the key back and cranked it again. STUPIDLY, while doing this, I turned the steering wheel for some reason.
When the car started, the EPAS warning light was on - no problem, I thought, probably a brownout on the EPAS ECU, I'll just turn the ignition off then back on.... Light was still on
I disconnected the battery overnight, just in case it was a fault that could be cleared in this manner. Connected it back the next day - still on. The only other thing I could think of was that the EPAS ECU was possibly confused as to where the steering wheel was and that it may need proxy aligned...
Went to Arnold Clark FIAT in Aberdeen and got the fault read. Turned out to be :
Electric motor: O.C., S.C. to Ground or S.C. to +VBatt
At this stage I was hugely confused as to why this might be the case, the car has covered only 30k miles and had provided faultless service without the merest hint of impending failure; it seemed massively coincidental that the motor chose that precise moment to fail!
Fiat recommended replacing the entire column, but the fix cost seems an uneconomical repair given the market value of the car and, being a tinkerer, coupled with the fact that the fault was allegedly associated with a semi-serviceable component, I decided to have a look inside and see if I could at least diagnose the problem more specifically.....:yum:
Following disconnecting the battery again over night, I removed removing the lower steering-column shroud (via 4 Allen bolts) and was faced with the motor:
The motor wiring consists of two multiplugs, one which I assume is the supply with 3 hefty wires and a second connector which I am guessing is the drive signals for the (stepper?) motor. I unplugged both connectors from the EPAS ECU.
The motor is held in place with 3 Torx bolts (there is another one out of view at the top/back of motor photo - I used the height adjust to set the column to it's lowest position to get it more easily). I do not own a Torx bit this small, but I found an 8mm regular socket fitted perfectly.
After the last bolt was free, I removed the motor by pulling gently, taking extreme care not to rotate it as I did so.
I immediately took a photo of the motor shaft and noted that there was yellow paint on the splined shaft - I used this as a reference for refitting later:
Notice there are other things in here that one may not expect! Relays!
Running a Google search on these Siemens part numbers revealed an Italian site with a thread devoted to this and magnificent pictures of these relays. Not being fluent in anything other than ropey-at-best Scottish, I translated the page using Yahoo Babel translator. It's not great, but you can get the gist, besides the photos are the important bit:
http://66.196.80.202/babelfish/translate_url_content?.intl=us&lp=it_en&trurl=http%3a%2f%2fwww.pctuner.net%2fforum%2f1246844-post56.html
The first picture describes where you shouldn't see a short circuit. Being that these are hefty-looking power wires and that my fault is related to a short, this was my first series of tests. Sure enough, indicated by the continuity check beep on my multimeter, I had a short between pins 1 & 3 on my relay nearest the closest together pair of bolt holes.
I needed to get the PCB out the motor to test it properly so I desoldered the 6 power connections from the PCB and removed it:
Wasting no time, I then desoldered the relay (8 pins) and the add-on legs (worst design ever) :
...A super-careful dissection of the offending device then took place - first I used a scalpel to very, very carefully cut the base from the relay:
After doing that, I slid out the innards and found the contact arm to be melted in place on one side only, the right as you look at the picture. I gently freed it and noticed that, interestingly, the plastic had melted, not the contacts themselves:
Finally......
This was giving rise to the “short”! I carefully removed all of the melted plastic and rebuilt the relay, tested it extensively before rebuilding and re-installing the motor. I was satisfied that both were operating as good as new.
I made certain +/- 1 tooth that the splined shaft was reinstalled in the correct position then I checked and double checked the motor to EPAS ECU connections and then re-connected the battery. I started the car to be faced again with the warning light :bang:
Turned the ignition off then back on and the light was GONE!:slayer: I slowly moved the wheel from lock to lock, the power steering was a little jittery, but I am not 100% that it wasn't me being excited. However, when I got to the right-hand lock, the wheel seemed to “jump” to back to the left before the EPAS died again; several re-starts and back to square one. Tested the motor again, relays are still fine all fuses ok
Questions/comments:
1. I speculate that, since it failed at the extreme position of movement, the EPAS ECU has somehow lost where the wheel position is, how can this be the case when I was so careful when taking out the motor and putting it back?
Surely only de-synchronising the TDC sensor in the upper steering assembly with respect to the encoders in the column could cause this? The motor shaft position is surely irrelevant being that it has no (evident) encoders.
2. Does anyone know this motor inside-out? Does it indeed have encoders?!
3. Does this fault give rise to a logged error that would explain why the light is on?
4. Does anyone know how this relay, multi-supply setup works? Is it like a DC windscreen wiper motor where, by powering a brush closer to the oppositely-poled one, the motor speed is increased, perhaps effecting “City mode”?
5. Any other factors I am overlooking?
Options:
1. Take it back to Fiat to be re-scanned and, if applicable, pay to have it calibrated and the fault cleared. I am reluctant to give Fiat another £29+ for this as it's a total gamble.
2. Take it to an independent garage and ask them if they can scan it and clear the code if it is stored - also a gamble, but it may be more justifiable seeing as this SC problem is now rectified.
3. Buy the complete column from Fiat (virtually unjustifiable when weighed against the value of the car).
4. a)Still very expensive - buy a BBA Reman 2-year warranted unit http://www.bba-reman.com/content.aspx?content=fiat_punto_brava_bravo_electric_power_steering_failure
b) I have read that this doesn't need calibrated since it is a complete system. Can anyone confirm or refute this? How can this be true, given that the rack position is integral to getting the steering position straight both physically and from the EPAS system standpoint?!
5. I have heard reports of diode failure as a common problem with the system, being that my EPAS suffered immediate failure with no preceding loss in performance and that a diode failure could be an effect or contributor of the relay failure. If anyone knows where this diode actually is, I'd love to know!
5. Continue investigations with the motor, perhaps replacing the relays with new units (the part now obsolete - ooh, I wonder why?!). That said though, to the best of my ability to test them, they are 100%.
Again, sorry for the long post, but if this route costs only the price of 1, or 2 at the most, diagnostics and a couple of relays, it sure as hell beats the several hundred pound “new column and that’s that” route and may help other people in the similar circumstance of weighing up getting rid of their pride and joy on the strength of this poorly designed subsystem failure.
Any and all questions and comments welcomed.
I may have a the beginnings of low cost fix route for some power steering failures that relate to the motor.
There are a lot of threads on this topic and I have read the EPAS stickied guide before posting.
Here's my story - sorry for the long post:
About a week ago, I turned over the ignition to start my X-reg 1242 Mia. I didn't crank it for long enough to start it, so I turned the key back and cranked it again. STUPIDLY, while doing this, I turned the steering wheel for some reason.
When the car started, the EPAS warning light was on - no problem, I thought, probably a brownout on the EPAS ECU, I'll just turn the ignition off then back on.... Light was still on
I disconnected the battery overnight, just in case it was a fault that could be cleared in this manner. Connected it back the next day - still on. The only other thing I could think of was that the EPAS ECU was possibly confused as to where the steering wheel was and that it may need proxy aligned...
Went to Arnold Clark FIAT in Aberdeen and got the fault read. Turned out to be :
Electric motor: O.C., S.C. to Ground or S.C. to +VBatt
At this stage I was hugely confused as to why this might be the case, the car has covered only 30k miles and had provided faultless service without the merest hint of impending failure; it seemed massively coincidental that the motor chose that precise moment to fail!
Fiat recommended replacing the entire column, but the fix cost seems an uneconomical repair given the market value of the car and, being a tinkerer, coupled with the fact that the fault was allegedly associated with a semi-serviceable component, I decided to have a look inside and see if I could at least diagnose the problem more specifically.....:yum:
Following disconnecting the battery again over night, I removed removing the lower steering-column shroud (via 4 Allen bolts) and was faced with the motor:
The motor wiring consists of two multiplugs, one which I assume is the supply with 3 hefty wires and a second connector which I am guessing is the drive signals for the (stepper?) motor. I unplugged both connectors from the EPAS ECU.
The motor is held in place with 3 Torx bolts (there is another one out of view at the top/back of motor photo - I used the height adjust to set the column to it's lowest position to get it more easily). I do not own a Torx bit this small, but I found an 8mm regular socket fitted perfectly.
After the last bolt was free, I removed the motor by pulling gently, taking extreme care not to rotate it as I did so.
I immediately took a photo of the motor shaft and noted that there was yellow paint on the splined shaft - I used this as a reference for refitting later:
Notice there are other things in here that one may not expect! Relays!
Running a Google search on these Siemens part numbers revealed an Italian site with a thread devoted to this and magnificent pictures of these relays. Not being fluent in anything other than ropey-at-best Scottish, I translated the page using Yahoo Babel translator. It's not great, but you can get the gist, besides the photos are the important bit:
http://66.196.80.202/babelfish/translate_url_content?.intl=us&lp=it_en&trurl=http%3a%2f%2fwww.pctuner.net%2fforum%2f1246844-post56.html
The first picture describes where you shouldn't see a short circuit. Being that these are hefty-looking power wires and that my fault is related to a short, this was my first series of tests. Sure enough, indicated by the continuity check beep on my multimeter, I had a short between pins 1 & 3 on my relay nearest the closest together pair of bolt holes.
I needed to get the PCB out the motor to test it properly so I desoldered the 6 power connections from the PCB and removed it:
Wasting no time, I then desoldered the relay (8 pins) and the add-on legs (worst design ever) :
...A super-careful dissection of the offending device then took place - first I used a scalpel to very, very carefully cut the base from the relay:
After doing that, I slid out the innards and found the contact arm to be melted in place on one side only, the right as you look at the picture. I gently freed it and noticed that, interestingly, the plastic had melted, not the contacts themselves:
Finally......
This was giving rise to the “short”! I carefully removed all of the melted plastic and rebuilt the relay, tested it extensively before rebuilding and re-installing the motor. I was satisfied that both were operating as good as new.
I made certain +/- 1 tooth that the splined shaft was reinstalled in the correct position then I checked and double checked the motor to EPAS ECU connections and then re-connected the battery. I started the car to be faced again with the warning light :bang:
Turned the ignition off then back on and the light was GONE!:slayer: I slowly moved the wheel from lock to lock, the power steering was a little jittery, but I am not 100% that it wasn't me being excited. However, when I got to the right-hand lock, the wheel seemed to “jump” to back to the left before the EPAS died again; several re-starts and back to square one. Tested the motor again, relays are still fine all fuses ok
Questions/comments:
1. I speculate that, since it failed at the extreme position of movement, the EPAS ECU has somehow lost where the wheel position is, how can this be the case when I was so careful when taking out the motor and putting it back?
Surely only de-synchronising the TDC sensor in the upper steering assembly with respect to the encoders in the column could cause this? The motor shaft position is surely irrelevant being that it has no (evident) encoders.
2. Does anyone know this motor inside-out? Does it indeed have encoders?!
3. Does this fault give rise to a logged error that would explain why the light is on?
4. Does anyone know how this relay, multi-supply setup works? Is it like a DC windscreen wiper motor where, by powering a brush closer to the oppositely-poled one, the motor speed is increased, perhaps effecting “City mode”?
5. Any other factors I am overlooking?
Options:
1. Take it back to Fiat to be re-scanned and, if applicable, pay to have it calibrated and the fault cleared. I am reluctant to give Fiat another £29+ for this as it's a total gamble.
2. Take it to an independent garage and ask them if they can scan it and clear the code if it is stored - also a gamble, but it may be more justifiable seeing as this SC problem is now rectified.
3. Buy the complete column from Fiat (virtually unjustifiable when weighed against the value of the car).
4. a)Still very expensive - buy a BBA Reman 2-year warranted unit http://www.bba-reman.com/content.aspx?content=fiat_punto_brava_bravo_electric_power_steering_failure
b) I have read that this doesn't need calibrated since it is a complete system. Can anyone confirm or refute this? How can this be true, given that the rack position is integral to getting the steering position straight both physically and from the EPAS system standpoint?!
5. I have heard reports of diode failure as a common problem with the system, being that my EPAS suffered immediate failure with no preceding loss in performance and that a diode failure could be an effect or contributor of the relay failure. If anyone knows where this diode actually is, I'd love to know!
5. Continue investigations with the motor, perhaps replacing the relays with new units (the part now obsolete - ooh, I wonder why?!). That said though, to the best of my ability to test them, they are 100%.
Again, sorry for the long post, but if this route costs only the price of 1, or 2 at the most, diagnostics and a couple of relays, it sure as hell beats the several hundred pound “new column and that’s that” route and may help other people in the similar circumstance of weighing up getting rid of their pride and joy on the strength of this poorly designed subsystem failure.
Any and all questions and comments welcomed.
Last edited:
