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. This is what happened to one technician and a SureTrack community member when their customer came in complaining their 2005 Ford Transit Connect 1.8L had both a battery and check engine light on. Let’s see how the technician solved this puzzle.
Diagnosis
Of course the technician started his diagnosis process with a quick scan. He found code P1632 – Smart Alternator Faults Sensor / Circuit. He inspected the alternator and accessory drive belt and found there was no noticeable damage. Then, with the engine at idle and all electrical loads off, he viewed live scan tool data and found the battery voltage was dropping steadily. With a multi-meter across the battery terminals to measure the battery voltage, he found the measured voltage matched the live scan tool data.
Continuing the search, he ran the engine, raised the speed to 2,000 RPM, used an inductive ammeter to measure the alternator maximum output and found the measured amperage did not increase. He even inspected the alternator wiring harness for any obvious flaws, but he still found nothing. Finally getting closer, he 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. At last, he found the problem!
Fix
This test proved the alternator wiring harness was the culprit. After replacing the harness and clearing the codes, he performed the road test and was able to verify it was fixed, giving the keys back to another satisfied customer.
Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read the Real Fix in the Mitchell 1 ShopConnection Blog.
