Nissan C1B84
00 ? (DIST SEN MALFUNCTION) - C1A17-49 ? (CONTROL UNIT (INTERNAL ELECTRONIC ERROR)) ACTION 1. Install the new Distance Sensor. 2. Add a foa
Quick answer
For a 2018 Nissan Leaf in the US, DTC C1B84-00 is documented with C1A17-49 when the Malfunction and Automatic Emergency Braking (AEB) warning lights are on. Nissan’s referenced service action is to install a new Distance Sensor and add a foam-related item; the supplied evidence truncates the remainder of that instruction.
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.
No sufficiently relevant embeddable video has been accepted for this diagnostic yet.
Videos are supporting material and never override OEM or regulator evidence.
1. What does C1B84 mean?
For a 2018 Nissan Leaf in the US, DTC C1B84-00 is documented with C1A17-49 when the Malfunction and Automatic Emergency Braking (AEB) warning lights are on. Nissan’s referenced service action is to install a new Distance Sensor and add a foam-related item; the supplied evidence truncates the remainder of that instruction.
2. Technical explanation
Verified NHTSA-published Nissan communication NTB18-057 identifies the combination of C1B84-00, described as “DIST SEN MALFUNCTION,” and C1A17-49, described as “CONTROL UNIT (INTERNAL ELECTRONIC ERROR).” The communication applies when the Malfunction and AEB warning lights are illuminated. Its stated action begins: “1. Install the new Distance Sensor. 2. Add a foa…” The complete second action is not established by the supplied verified evidence.
3. What system is affected?
Distance Sensor / Automatic Emergency Braking (AEB) warning system. The diagnostic record does not provide a more specific system name.
4. How serious is this code?
Unknown. The supplied verified evidence confirms warning-light illumination and a Nissan service procedure, but does not assign a severity level.
5. Symptoms you may notice
- Malfunction warning light on.
- Automatic Emergency Braking (AEB) warning light on.
- DTC C1B84-00 (DIST SEN MALFUNCTION).
- DTC C1A17-49 (CONTROL UNIT (INTERNAL ELECTRONIC ERROR)).
6. Possible causes
- Distance Sensor malfunction is indicated by C1B84-00.
- An internal electronic error in the control unit is indicated by C1A17-49.
- A more specific root cause is 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
- Arrange diagnosis by a Nissan dealer or qualified service facility.
- Provide the stored DTCs C1B84-00 and C1A17-49 and reference Nissan communication NTB18-057.
- Do not attempt distance-sensor replacement or other repair based solely on this summary.
10. Step-by-step troubleshooting
- Confirm whether the Malfunction and AEB warning lights are on.
- Confirm whether both C1B84-00 and C1A17-49 are stored.
- Have a qualified service facility evaluate the vehicle using Nissan communication NTB18-057.
11. When to contact service
Service attention is supported by Nissan communication NTB18-057 because it specifies installation of a new Distance Sensor for the documented warning-light and DTC condition.
12. What the service center may check
- Verify the Malfunction and AEB warning-light condition.
- Verify DTCs C1B84-00 and C1A17-49.
- Review and follow Nissan communication NTB18-057 for the applicable 2018 US Nissan Leaf.
13. Possible repair or resolution
- Nissan communication NTB18-057 states: install the new Distance Sensor.
- The communication also states to “Add a foa…,” but the supplied evidence does not contain the complete instruction.
14. Affected vehicles
- Nissan Leaf · 2018 · US
15. Related TSBs / service bulletins
- Nissan NTB18-057; NHTSA Manufacturer Communication 10144520; published August 7, 2018. It applies to the documented Malfunction and AEB warning-light condition with C1B84-00 and C1A17-49.
16. Recall information
- No recall information is established by the supplied verified evidence.
17. Official manufacturer information
Official source: NHTSA Manufacturer Communication 10144520, Nissan NTB18-057: https://static.nhtsa.gov/odi/ffdd/tsbs/TSBS_RECEIVED_2015-2019.zip#nhtsa_id=10144520
- NHTSA: NHTSA Manufacturer Communication 10144520: NTB18-057 · official_tsb
19. Frequently asked questions
What does C1B84 mean on a 2018 Nissan Leaf?
The supplied Nissan evidence describes C1B84-00 as “DIST SEN MALFUNCTION.”
What warning lights are documented with C1B84-00?
Nissan communication NTB18-057 documents the Malfunction and AEB warning lights being on when C1B84-00 and C1A17-49 are present.
What repair does Nissan specify?
The supplied evidence states to install a new Distance Sensor and begins a second instruction, “Add a foa…”. The complete second instruction is not available in the supplied evidence.
Is this information applicable to every Nissan Leaf?
The supplied applicability evidence identifies a 2018 Nissan Leaf in the US only.