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2018 NSX Hybrid System Warning and Engine Light - Intermittent

0

Mark S. · rep 0 · May 22, 4:55 AM · 1 replies · solved · Question

Vehicle: 2018 Acura NSX

Hello everyone,

I'm reaching out about an issue with my 2018 Acura NSX, which has about 25,000 miles. For the past few weeks, I've been getting an intermittent 'Hybrid System Warning' message on the dash, and sometimes the check engine light comes on along with it. The car seems to drive perfectly fine – no noticeable loss of power, no strange noises, and the hybrid system appears to be assisting as usual.

The warnings usually clear themselves after a few drive cycles or after the car sits for a while, only to reappear randomly. I haven't been able to pull any specific OBD codes related to the hybrid system, just generic engine codes when the CEL is on. Has anyone with an NSX experienced this? What should I be looking for?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:55 AM

0

ClearTheCode admin answer:

Intermittent 'Hybrid System Warning' and Check Engine Light on a 2018 Acura NSX can be tricky to diagnose without specific codes, but here are the most common culprits in hybrid vehicles, especially high-performance ones like the NSX:

  1. 12V Battery Health: This is surprisingly common. A weak or failing 12V auxiliary battery (which powers the car's conventional electrical systems and starts the engine) can cause a cascade of electronic issues, including false hybrid system warnings. The NSX's complex electronics are very sensitive to voltage fluctuations.
  2. Hybrid Battery Pack Issues: While less likely at 25,000 miles, individual cells or modules within the high-voltage hybrid battery pack could be experiencing an imbalance or degradation. The system monitors cell voltage closely, and any deviation can trigger a warning. This would typically require specialized diagnostic tools.
  3. Motor Generator Unit (MGU) or Inverter Issues: The NSX uses multiple MGUs (front and rear) and inverters to manage power flow. A fault in one of these components, even if intermittent, could trigger the warning. This might not immediately affect performance if other MGUs compensate.
  4. Wiring or Sensor Faults: Given the complexity, a loose connection, corroded wire, or a faulty sensor within the hybrid system (e.g., temperature, current, or position sensors) could cause intermittent warnings.
  5. Software Glitch: As with any modern, highly computerized vehicle, a software bug or calibration issue in the hybrid control module could be responsible for false warnings.

When to see a shop:

  • Immediately: Due to the complexity and high-voltage nature of the NSX's hybrid system, it is critical to take it to an authorized Acura dealership or a specialist shop with NSX-specific diagnostic equipment. Generic OBD-II scanners often cannot read the detailed hybrid system codes.
  • Do not attempt to diagnose or repair high-voltage components yourself, as there is a significant risk of electric shock.
  • Even if performance seems normal, these warnings indicate an underlying issue that could worsen and potentially lead to more costly repairs or even system shutdown if ignored. The dealership can perform a comprehensive hybrid system health check.
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