As Buckeye says check your entire charging system. Here at altitude we fight the same code on a daily basis and per Nissan the fix (at altitude ) is remove and clean battery and cables, charge battery as needed to perform load test. Results of load test must be obvious. And your battery must be strong. Install battery and start unit. Watch the amp draw as a weak starter can mimic the alternator. It must chargeat 14.10 volts or higher with an amp reading of at least 20 to not code out. Remember this is all at altitude but it shouldn't matter. If any reading is too low or if there is an anomaly fix and retest. Good luck and may the force be with you!we have seen this code happen as a result of jump starting a forklift so keep that in mind as well.