Battery not charging

Hello,

It is testing good off the vehicle because it is good and the bench test machine sends the proper signals to the alternator to charge. The fault lies with the vehicle not sending those signals.

In this case the body control module receives information from the current sensor and the engine control module controls the voltage sent to the field circuit of the alternator to allow it to charge.

The charging system on this model looks at vehicle information to determine when to excite the field circuit. This was part of a fuel saving design to lessen engine load.

What needs to be done is the gray wire from alternator to ECM checked for continuity. If it's good a scan tool with live data and bidirectional control will be required to activate the charging system to see if it's a bad driver in the ECM or some other issue

I'll post the charging system diagram below.