Nissan B2191
Difference of key
Quick answer
Nissan DTC B2191 means “Difference of key.” Verified Nissan service information links it to possible interference with NATS (Nissan Anti-Theft System) key signals.
This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.
Watch Videos
Relevant videos play here without leaving this diagnostic page.
Videos are supporting material and never override OEM or regulator evidence.
1. What does B2191 mean?
Nissan DTC B2191 means “Difference of key.” Verified Nissan service information links it to possible interference with NATS (Nissan Anti-Theft System) key signals.
2. Technical explanation
Nissan’s NTB13-107F manufacturer communication states that interference with NATS key signals can cause DTC B2191 (Difference of key) to be stored in the BCM. The same communication identifies P1615 (Difference of key) as a related ECM code. The documented condition may be intermittent and difficult to diagnose.
3. What system is affected?
The verified evidence identifies the BCM as the module where B2191 may be stored and refers to NATS key signals. A more specific system classification is not yet established by verified evidence.
4. How serious is this code?
Unknown. The supplied verified evidence does not assign a severity level.
5. Symptoms you may notice
- NATS key not detected.
- Vehicle may not start, described by Nissan as no response when the key is turned.
- Immobilizer warning light illumination.
- Intermittent operation of the door request switches.
- The condition may be intermittent and difficult to diagnose.
6. Possible causes
- Possible interference with NATS key signals. Further root causes are not yet established by verified evidence.
7. Can I still drive the vehicle?
Not yet established by verified evidence.
8. Can I charge the vehicle?
Not yet established by verified evidence.
9. What you can safely do
- If the vehicle does not start or the immobilizer warning light is illuminated, arrange Nissan service diagnosis.
- Document whether the issue is intermittent and whether door request switches are also operating intermittently.
- Use Nissan’s applicable diagnostic information; do not attempt anti-theft, BCM, or high-voltage repairs without qualified service support.
10. Step-by-step troubleshooting
- Nissan NTB13-107F directs technicians to its Supplemental Diagnosis / Information sections when the documented symptoms occur or are reported.
- Because the verified communication describes the concern as potentially intermittent and difficult to diagnose, provide the service facility with details of when the condition occurs.
11. When to contact service
Contact a Nissan dealer or qualified Nissan service facility if B2191 is stored, especially if the vehicle does not start, the immobilizer warning light illuminates, or the condition recurs.
12. What the service center may check
- Confirm whether B2191 is stored in the BCM.
- Assess the reported NATS key-detection concern and the symptoms documented in Nissan NTB13-107F.
- Follow the Supplemental Diagnosis / Information procedure referenced in Nissan NTB13-107F.
13. Possible repair or resolution
- A specific repair resolution is not yet established by the supplied verified evidence.
14. Affected vehicles
- Nissan ARIYA · 2001–2023 · US
- Nissan Hyper-Mini · 2001–2023 · US
- Nissan Leaf · 2001–2023 · US
15. Related TSBs / service bulletins
- Nissan NTB13-107F, published April 27, 2023, is an official NHTSA-hosted manufacturer communication. It documents that interference with NATS key signals may lead to intermittent key-detection concerns, immobilizer warning illumination, B2191 in the BCM, and P1615 in the ECM.
- Source: https://static.nhtsa.gov/odi/tsbs/2023/MC-10235707-0001.pdf
16. Recall information
- No recall information is established by the supplied verified evidence.
17. Official manufacturer information
Verified source: NHTSA-hosted Nissan manufacturer communication NTB13-107F (MC-10235707-0001), published April 27, 2023: https://static.nhtsa.gov/odi/tsbs/2023/MC-10235707-0001.pdf
19. Frequently asked questions
What does Nissan code B2191 mean?
It means “Difference of key.”
Where is B2191 stored?
The verified Nissan communication states that B2191 may be stored in the BCM.
Can B2191 prevent starting?
Nissan states that NATS key interference can cause the key not to be detected and may result in no response when the key is turned.
Is B2191 intermittent?
It can be. Nissan states that the documented symptoms are usually intermittent and can be difficult to diagnose.
Is P1615 related to B2191?
Yes. Nissan’s communication identifies P1615, also described as “Difference of key,” as an ECM code that may be stored when NATS key-signal interference occurs.