Discovery 3 Alternator Question

[alicedisco]

I had a friend who has a Bearmach Landrover OBD reader plug it into my 2006 V6 Disco 3, as my battery light comes on for a couple of minutes over a 20km drive to or from work.
It produced this fault message : P063D IDM Pulsewidth Not Defined.
Anyone have any idea what this means?

[sierrafery]

there might be some glitch with that code reader then or with the car's ECU cos the P063D is specific for Peugeot(as the engine is made by them it might be relevant) = P063D OBD-II Fault Code, Generator Voltage - Peugeot (http://upkeep.us/OBDII/OBD2/Peugeot/piart.php?art=755) and the description fits with Ford fault code P1357 cos IDM = ignition diagnostic monitor P1357 Ford Ignition Diagnostic Monitor Pulsewidth Not Defined OBDII Engine Light Trouble Code | Engine-Codes.com (http://engine-codes.com/p1357_ford.html)

so corroborated with the fact that your battery charging warning comes on i'd say that it might be a problem with the alternator's regulator or the circuit to ECU

can't you try with a different tester too?