Ever heard of a Smart Alternator Charging System? On Fords equipped with this system, it is used to make sure the alternator only charges when needed to reduce emissions and conserve fuel. But when this system fails, you may not be charging at all. Follow this Real Fix to see how to diagnose a code P1632 on this Ford Transit Connect.
Vehicle
2005 Ford Transit Connect 1.8L
Title
Check Engine Light Is On, Battery Light On, Replaced Alternator Wiring Harness
Complaint
The customer states that both the battery light and the check engine light are on.
Cause
Connected a scan tool and found code P1632 – Smart Alternator Faults Sensor / Circuit. Visually inspected the alternator and accessory drive belt and found there was no obvious damage. With the engine at idle and all electrical loads off, viewed live scan tool data and found the battery voltage was dropping steadily. Used a multi-meter across the battery terminals to measure the battery voltage and found the measured voltage matched the live scan tool data. Ran the engine, raised the engine speed to 2,000 RPM, used an inductive ammeter to measure the alternator maximum output and found the measured amperage did not increase. Visually inspected the alternator wiring harness for any obvious faults and found no obvious damage. Used the multi-meter to check the continuity of the alternator wiring harness and found there were excess resistances which increased as it was wiggled to simulate road shock. These test results verified the alternator wiring harness was faulty.
Correction
Replaced the alternator wiring harness, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.
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