Ford Focus Mk2 TDCi 1.6 2007

I've hooked up my laptop and run some scans due to a permanent battery light on the dash.

Everything is pointing back to the alternator smart charge circuit/sensor. Has anyone fixed this before, if so / how much did it cost / how hard was it ?

Back on my 1.8tdci 2006 the wire had snapped near the ecu. Cost around £120 iirc from dealer to fix...i didnt have the tools to take body panel off to get to it....and i didnt trust myself lol

not quite that easy youre laptop wont tell you the actual fault start at the begining whats the battery voltage does it have a faulty cell is it the correct type of battery all these can send a signal back to the circuit to say theres an issue which will give a false reading to test the smart charge is not something you can do at home or with a laptop

Probably a wire broken between alternator and pcm

Are you having starting/battery issues or just the light on? Have you got a multimeter to check charging voltage?

brand new battery about 6 months ago.

Battery light on no issues starting

Checked voltage. Its what I am expecting no low output or too high.

Laptop diagnostics points issue at the circuit ..

Doesn't explain much is it a silver calcium battery? If not it'll send a signal back if it was a smart charge fault then the voltages wouldn't be as expected if its not too low the smart charge is working with engine running 14.4v a simple battery light can be the cluster doesn't matter what diagnostics say they point in the general direction if the circuit is getting a faulty signal due to incorrect battery over or under charging or a broken wire it will show up as a fault in the circuit but its not the circuit causing the issue

100% correct battery type.

I'm pretty sure its a sensor issue, but not sure about the process of replacing it ?

Kind of having the same problem.  would a smart charge fault also make the engine start making a whining noice between 1000 and 2000 revs? Car also had steering assistance failure come up and cut out a few times while mid corner. 

7 hours ago, Chedaz said:

Kind of having the same problem.  would a smart charge fault also make the engine start making a whining noice between 1000 and 2000 revs? Car also had steering assistance failure come up and cut out a few times while mid corner. 

Unfortunately that sounds more like the alternator itself (the whining & potentially the power dropping out/down so the PAS turns off).

Mine was doing that prior to the alternator & battery failing.

I'm having similar issues. New battery and alternator but still get battery light on occasionaly. Puts out 13.7 volts when light is on.

This is a common fault, the wiring loom flaps about at the front and over time the wire which goes into the alternator tends to snap. A good garage or auto electrician can splice it back together but you may need a replacement section of the loom.

just found out you can disconnect the smart charge system by unplugging at alternator and at battery ... this turns alternator into a standard alternator charging at 14v 

Disconnecting the Smart Charge connector should only be done for diagnostic/testing purposes.

When the Smart Charge connector is disconnected the regulator of the alternator will continuously work at its maximum capacity. This will overcharge and damage the battery

On 9/24/2020 at 10:21 AM, JW1982 said:

Disconnecting the Smart Charge connector should only be done for diagnostic/testing purposes.

When the Smart Charge connector is disconnected the regulator of the alternator will continuously work at its maximum capacity. This will overcharge and damage the battery

I have a similar issue. I like to test whether my smart charge fault, can I remove the smart battery charger fuse in the fuse box to test it?

22 hours ago, M Lam said:

I have a similar issue. I like to test whether my smart charge fault, can I remove the smart battery charger fuse in the fuse box to test it?

That won't test the wiring, which by far the most likely culprit.

11 hours ago, FatHead1979 said:

That won't test the wiring, which by far the most likely culprit.

How about remove the smart charge plug from alternator? Can I test it that with this method?