ferguson_tom Posted July 7, 2015 Report Share Posted July 7, 2015 Hi Everyone Another one for the PW motoring gurus, my mark 3 TDCI mondeo stripped its alternator belt the other day and when it did took out the 3 wires for the smart charge to the alternator. My mechanic has reconnect the wires and checked continuity between them and all looks good. Also the F30 fuse has been replaced as this blew. Last night i tried resetting the ECU by disconnecting the battery all night. On the diagnostics no fault code comes up. When you disconnect the smart charge the alternator kicks out 13.5ish volts and is stable when load is added or revs increase etc, when you reconnect the smart charge the voltage fluctuates between 12.5 and 13.5 volts however it doesnt shoot up when you rev it or drop too much when you put a load on it just continually fluctuates. I have a concern its the ECU at fault as we cant think of anything else it might be, anyone have any ideas? Thanks, Tom Quote Link to comment Share on other sites More sharing options...
yod dropper Posted July 7, 2015 Report Share Posted July 7, 2015 If you don't get any joy here check out the talkford forum, lots of really good past threads, helpful people, ford technicians and whatnot. Quote Link to comment Share on other sites More sharing options...
hawkfanz Posted July 7, 2015 Report Share Posted July 7, 2015 I,m on my forth mondeo,but never had anything like that happen,but as yd says go on talkford forum I,m sure you,ll find the answere there. Quote Link to comment Share on other sites More sharing options...
Andy 01 Posted July 8, 2015 Report Share Posted July 8, 2015 So whats your actual concern with the vehicle ?? Is the MIL or the charge light on ? The purpose of Smart Charge is to alter the charging rate to demand, based on a calculated battery temperature. Voltage going up and down is the purpose of the system. If you have a warning light on, or are not charging at all, thats a different matter, but you will need access to an oscilloscope for me to be able to talk you through the diagnostics. Does the vehicle have the correct battery fitted ? It must be a silver clacium, denoted by CA on the battery. Smart charge can not work correctly with a lead acid battery, denoted by PB on the battery. Quote Link to comment Share on other sites More sharing options...
ferguson_tom Posted July 8, 2015 Author Report Share Posted July 8, 2015 Hi Andy All was working perfectly before the auxillary belt went and broke the 3 cables to the alternator last week so battery and everything is the same only difference is the cables are now soldered together rather than joined by the quick release connector. When you first start the car the battery light is out, after about 20-30 seconds it comes back on again until engine is switched off. When you disconnect the smart charge the alternator goes to default mode and gives out 13.5 volts like it should, when you reconnect the smart charge the voltage fluctuates between 12.5 and 13.5volts. All readings taken at the battery. I am sure we have an oscilloscope at work but my boss is on holiday till next week so have to get it then. I am going to try and chase the cables back further closer to the ecu to see if they have been damage further up as well as where they broke. For time being I have disconnected the smart charge system as car still runs fine without it and this stops headlights flickering from the constant fluctuating voltage from the smart charge. Many thanks in advance. Tom Quote Link to comment Share on other sites More sharing options...
jonny thomas Posted July 8, 2015 Report Share Posted July 8, 2015 Don't know for sure but check it doesn't over charge if the smart charge is disconnected Quote Link to comment Share on other sites More sharing options...
HAYBURN Posted July 8, 2015 Report Share Posted July 8, 2015 HI, have a read through this it may help..read post 10 problem with wire at plug connector.. ATB Quote Link to comment Share on other sites More sharing options...
ferguson_tom Posted July 9, 2015 Author Report Share Posted July 9, 2015 Don't know for sure but check it doesn't over charge if the smart charge is disconnected Charges at 13.5 volts when disconnected HI, have a read through this it may help..read post 10 problem with wire at plug connector.. ATB Can you please try and reattach what ever it is...unless I am missing it. Cheers. Quote Link to comment Share on other sites More sharing options...
HAYBURN Posted July 9, 2015 Report Share Posted July 9, 2015 Charges at 13.5 volts when disconnected Can you please try and reattach what ever it is...unless I am missing it. Cheers. Sorry forgot to put link up There is two pages hope it helps http://www.rac.co.uk/forum/showthread.php?5813-Mondeo-Electrical-Fault Quote Link to comment Share on other sites More sharing options...
Andy 01 Posted July 9, 2015 Report Share Posted July 9, 2015 Right, I'm back. Pin 3 of the smart charge plug MUST mirror battery voltage ! The tollerance is no greater than a 0.2v difference. If you get 13.5v at the battery engine running, you MUST have the same at pin 3. You may have high resistance / volt drop through the repaired wire ? Pin 1 is the command line from the ECU to the alternator.This nees to be scoped via back probe. You should see a good square wave signal (with no noise or hash), which alters in frequency as the electrical load is altered. (Switch heated screen / headlights on, and the frequency should change). Iy you have a concern with this signal, disconnect plug from alternator and test again. If signal corrects its the alternator. If its still bad, its a wiring concern or the engine ECU. Pin 2 is the monitor line from the alternator back to the pcm. Test the same on a scope as above. But, this time the signal should always remain constant, regardless of the electrical demand. If you have a concern with this signal, its a wiring concern or a concern with the smart charge electronics in the alternator. Hope that helps. Andy Quote Link to comment Share on other sites More sharing options...
Andy 01 Posted July 9, 2015 Report Share Posted July 9, 2015 Bloody cheek !!! Post 6 in the RAC link above is what I wrote for another motoring forum ! Been copied and pasted and claimed as his own. I know its mine, as I put pins 1 and 2 the wrong way round (it was late at night), and corrected it later in another post the next day. The info I put above is the correct way round Quote Link to comment Share on other sites More sharing options...
ferguson_tom Posted July 9, 2015 Author Report Share Posted July 9, 2015 Andy your a diamond thankyou very much. I can try the first test this evening with voltmeter and the other two next week when i get my hands on the ocilloscope. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.