2011 Intermittent Electrical Issue

[tsteves5]

2011 Journey, 3.6 V6, ~150,000 miles

 

I’ve been looking through some older threads on this site and have struggled to find a solution.  My 2011 has started randomly showing the battery light instrument cluster.  Sometimes it will happen twice per day, the next time it might take weeks to show up again.  It’s happened when the car is idling, and when the car is moving.  Sometimes only the battery light shows up, sometimes other warning lights come with it (AWD, ABS, etc…).  Stopping and re-starting the vehicle always clears the battery light and any other lights.  The vehicle has not died while driving yet.

 

So far, I’ve done the following.  Nothing has fixed the issue yet.

 

-Load tested the 1 year old battery, it still tests strong.

-Cleaned and inspected the battery cables and terminals.

-Tested the voltage of the system with the battery light on, ~14.3 volts.  If the alternator is failing, it’s only a very short hiccup/failure.

-Cleaned and inspected the engine compartment grounds.

-Removed, cleaned and inspected the PCM/ECU connectors.

-Cleaned and tightened the alternator cable connections.

-Cleaned the battery current sensor connector (on the battery terminal).

 

It is possible that the alternator fails and then quickly recovers?  I’ve never seen this before.  It seems that the most likely culprit is the PCM/ECU, but other threads with similar issues on this site seem to indicate that a PCM/ECU replacement rarely fixed the issue.

 

I appreciate any thoughts that anyone might have.

Edited May 2, 2022 by tsteves5

[John/Horace]

Weird issue. The small wire going to alternator is linked to pcm/ecm so it could trigger battery light coming on.

But measuring 14.3 when light is on I think means light should not be on at all. What is the gauge cluster showing for voltage when light is on.  Bad drive pulley coupler could also trigger battery light, but again voltage would be low.

 

When my wife’s alt failed it was intermittently at 10-11 volts charging, then completely failed. Voltage on small wire at alt when the light is on would be useful. It has to be a good strong full battery voltage signal.

[tsteves5]

Thanks for the suggestions.  I'll try to get the voltage on the small alternator control wire next time it fails.  It seems to latch the battery light, so in the event of a quick failure and recovery the battery light will stay on until the vehicle is stopped and re-started again.  It might make it tricky to catch.

 

I didn't realize those alternators have decoupler pulleys on them.  That might be part of the problem too iif the pulley fails (decoupled) incorrectly but quickly recouples.

[John/Horace]

Decoupler can be changed by itself, awkward with alt in place.  Our alt failed at 100k miles; very strong burning smell, decoupler was still working fine. The alternator It is a Denso factory unit; a very good brand name.

 

I think 2015 they added a plastic top guard to prevent oil from valve cover leaking into alternator. The dealer Mopar  rebuild I used was good price, had a 2 year warranty and contained 2 new studs and the now standard plastic cover for top of alternator.