When the battery warning light comes on but the vehicle is charging as it should, you need to figure out what could cause that issue. SureTrack community member Richard_C had a Honda Pilot in their shop where the battery warning light is always on but no issues are found immediately. They posed the question to the community, and with the help of fellow community member ericsautomotive and others, they were able to resolve the issue.
The following Real Fix summarizes the interaction between them in the community that led to the solution.
2012 Honda Pilot EX 3.5L
Battery warning light on, replaced alternator.
Customer complains that battery warning light is on but battery is being charged.
Diagnostic Steps Performed/Parts Replaced
Checked customer’s complaint and the battery warning light turns on when the car is on. It stays on as long as the car is running and is always solid. Voltage sits at 14.0V and never moves more than 13.9-14.2V when turning accessories on and off along with revving the engine. Scanned vehicle. Found some Control Motor Circuit codes but in the BCM. I assume those are for the airflaps and shouldn’t be the issue. Any hot tips to diagnose? I get the feeling that the alternator com line is bad or the alternator itself. Had a 2007 CRV in with the same issue. Tried an ELD, but didn’t fix it. My understanding is that when the ELD goes bad, voltages get a bit erratic. Never resolved it as the CRV runs fine. Customer just lived with the light.
Followed troubleshooting guide in ProDemand. When we unplugged the alternator, the warning light went off temporarily. We commanded the diagnostic test on the IC which showed all warnings would blink indicating proper operation of the cluster. We changed the alternator and the light turned off. The alternator was charging correctly but the L output was faulty.
Replaced alternator, battery warning light no longer comes on.
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