AU
B1714

DTC B1714 indicates the SRS (Supplemental Restraint System) control unit detects the right curtain airbag (head protection curtain/side curtain) inflator circuit resistance remains above the calibrated threshold (normal range typically 1 — Seal U

Safety System

DTC B1714 indicates the SRS (Supplemental Restraint System) control unit detects the right curtain airbag (head protection curtain/side curtain) inflator circuit resistance remains above the calibrated threshold (normal range typically 1.5-3.5 Ω, depending on vehicle calibration).

The SRS ECU periodically monitors each airbag inflator's resistance via an internal Wheatstone bridge or constant-current source circuit.

Excessive resistance indicates a high-impedance point in the inflator circuit.

Potential causes include poor connector contact, a partial open circuit in the wiring harness, or an aging inflator.

This constitutes a hard or intermittent fault.

During a side impact, the right curtain airbag may fail to deploy within the specified time (delayed deployment) or fail to deploy entirely.

The system illuminates the airbag warning light, and the front side airbags and seat belt pretensioners may enter fail-safe mode.

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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Right curtain airbag connector (usually located inside the C-pillar trim or at the rear of the roof side rail) is loose, has backed-out terminals, or shows oxidation or corrosion, increasing contact resistance (common in vehicles exposed to deep water or high humidity).
  • 2Repeated removal and installation or pulling during seat adjustment partially breaks the internal copper wire of the airbag wiring harness in the A-pillar/C-pillar trim panel transition area, resulting in a high-resistance intermittent connection.
  • 3Aging or a batch defect in the right curtain airbag inflator internal squib causes internal resistance to increase abnormally as temperature rises.
  • 4Enlarged SRS control unit (ACU) connector pin cavities or oxidized terminal surfaces add sampling circuit contact resistance to the curtain airbag circuit.
  • 5Vehicle modifications (such as window tinting or routing dash cam wiring) inadvertently damaged or pinched the right curtain airbag wiring harness, causing hidden damage.
What To Do
  • 1
    Safety preparation: Disconnect the low-voltage battery negative terminal and wait at least 90 seconds (to fully discharge the SRS capacitor). Never measure the airbag circuit while energized.
  • 2
    Initial diagnosis: Use VDS or a dedicated diagnostic tool to read the complete DTC information and freeze frame data. Confirm whether B1714 is a current or history fault. Record the ambient temperature when the fault occurred (low temperatures may affect contact resistance).
  • 3
    Visual inspection: Remove the right C-pillar trim, rear edge of the headliner, and D-pillar trim (depending on model). Verify the curtain airbag module connector (usually marked R-CAB or R-SAB) is fully locked. Inspect the terminals for green oxidation, burning, or backed-out pins.
  • 4
    Harness continuity test: Disconnect the wiring harness from the SRS ECU connector. Measure the harness resistance from the ECU connector to the curtain airbag connector using a low-impedance multimeter (0.1 Ω resolution). Normal resistance is less than 0.5 Ω. If resistance exceeds 1 Ω, inspect the harness transition points at the A-pillar and C-pillar (typically equipped with yellow shorting clips or adapter connectors).
  • 5
    Curtain airbag unit test (professionals only): Fully power down the vehicle. Measure the curtain airbag inflator resistance using a dedicated airbag tester (or the equivalent resistance substitution method specified in the repair manual). If the resistance is greater than 3.8Ω or unstable, replace the right curtain airbag assembly.
  • 6
    Swap verification (if the vehicle model supports this): If the left and right curtain airbags are the same model, carefully swap the left and right connectors (for diagnosis only; verify there is no risk of airbag deployment). Observe if the fault code transfers to the left side to confirm whether the curtain airbag or the wiring harness is faulty.
  • 7
    Repair and verification: Clean the oxidized connector (use electrical contact cleaner; never use sandpaper on gold-plated terminals). Replace the connector or curtain airbag if necessary. Restore all connections, power on the vehicle, and clear the fault code. Execute the 'Collision Output Test' or use the diagnostic tool's 'SRS self-test' function. Confirm the current fault changes to a 'historical fault' and can be cleared. Perform a road test to confirm the fault does not recur.
Real-World Cases
BYD DTC AI Analysis

Corroded C-pillar connector causing intermittent high resistance

✓
A 2019 BYD Yuan EV came in with an intermittent SRS warning light on the instrument panel. DTC B1714 was intermittent. Inspection found the vehicle had been through water. The right C-pillar curtain airbag connector showed green copper corrosion inside. Since the connector sits at the bottom of the C-pillar, water can easily enter during wading. After cleaning the connector and applying conductive grease, the resistance returned to normal. Advised the owner to check the door seals to prevent further water entry.
BYD DTC AI Analysis

Loose wiring harness connection after accident repair caused fault

✓
2021 BYD Tang. DTC B1714 kept returning after right rear-side accident repairs. The accident required sheet metal repairs to the right B and C pillars; during the repairs, the curtain airbag harness was stretched. Inspection found 80% of the copper strands fractured at the B-pillar trim clip, with only a few strands left connected, causing high resistance. Replaced the damaged harness section using genuine OEM yellow airbag wire — never substitute standard wire. Fault resolved.
BYD DTC AI Analysis

Curtain airbag internal resistance aged beyond specification

✓
A 2020 Qin petrol variant with 80,000 km had a constant SRS light and current DTC B1714. Harness continuity was normal at 0.3Ω. The curtain airbag resistance measured 4.2Ω cold (out of spec) and 6.5Ω hot, indicating aged initiator resistance in the gas generator. Replaced the right curtain airbag assembly (requires headliner removal; note curtain roll direction), then coded the module and cleared the fault.
BYD DTC AI Analysis

Enlarged SRS ECU connector pin sockets causing poor contact

✓
2019 BYD Song MAX. Intermittent B1714 DTC, temporarily disappeared after reseating the connector. Further inspection found enlarged terminal sockets on the SRS control unit (beneath the centre console) for the curtain airbag circuit, causing insufficient contact pressure with the curtain airbag terminals. Restored terminal clamping force using a specialised terminal removal tool, or replaced the entire SRS ECU connector housing. Fault permanently resolved.
Other Seal U Fault Codes
B1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.