P1105
NissanP1105 Nissan: Indicates that the Engine Control Module (ECM) has detected a malfunction in the charging system associated with the upper or primary alternator, specifically concerning its output or control circuit in a dual alternator setup.
High SeverityThis code signifies an issue with the upper alternator in a dual alternator setup, or the primary charging unit. If left unaddressed, it can lead to battery discharge, causing vehicle breakdown and loss of electrical functions.
⚠️ Before You Begin (Safety First)
Always disconnect the battery before working on electrical components. Be cautious of rotating belts and hot engine parts. If the vehicle loses power while driving, pull over safely immediately.
Common Symptoms
- Battery warning light on
- Dim headlights
- Slow or no crank condition
- Flickering interior lights
- Erratic accessory operation
- Possible stalling while driving
Common Causes
- Faulty upper alternator
- Defective voltage regulator (if external to alternator)
- Wiring harness damage or loose connections
- Blown fuse in charging circuit
- ECM malfunction (less common)
Frequently reported on: Nissan Titan (2004-2015), Nissan Armada (2005-2015), Nissan NV2500/3500 (2012-2020)
Diagnostic Steps
- Inspect the battery terminals for corrosion and ensure they are tight.
- Visually check the alternator belt for cracks, fraying, or looseness.
- With the engine off, use a multimeter to check the battery voltage.
- Start the engine and recheck the battery voltage; it should be higher (around 13.5-14.7V) if the alternators are charging correctly.
- Check accessible fuses related to the charging system in the under-hood fuse box.
- If possible, visually inspect the wiring harness leading to the upper alternator for damage or loose connections.
👨🔧 When to Call a Professional
If you observe persistent charging system warnings, dimming lights, or if you are uncomfortable diagnosing complex electrical systems, it is highly recommended to consult a certified professional to avoid further damage.
Commonly Asked Questions
What does 'Dual Alternator Upper Fault' mean?
It means the vehicle's computer has detected an issue with the primary or upper alternator's ability to charge the battery or operate correctly within the electrical system.
Can I drive my Nissan with a P1105 code?
It is not recommended to drive for long distances. A failing alternator can lead to a dead battery, leaving you stranded and potentially damaging other electrical components.
How can I confirm if the alternator is truly bad?
After checking basic connections and fuses, a professional can perform a load test on the alternator and battery to determine if the alternator is outputting sufficient voltage and current.
Is P1105 always about a physical alternator failure?
Not always. While a faulty alternator is common, the code can also be triggered by issues with the wiring harness, voltage regulator, or even a blown fuse in the charging circuit.
What is the typical cost to fix a P1105 code?
The cost varies significantly based on the root cause. If it's a simple wiring fix, it might be inexpensive. Replacing an alternator can range from $400 to $900 or more, including parts and labor, especially for dual alternator systems.