AU
B1719-00

DTC B1719-00 indicates the SRS (Supplemental Restraint System) control unit detects an abnormally low-resistance connection (short circuit) between the Driver Knee Airbag squib circuit and the vehicle power supply (B+) — Seal U

Safety System

DTC B1719-00 indicates the SRS (Supplemental Restraint System) control unit detects an abnormally low-resistance connection (short circuit) between the Driver Knee Airbag squib circuit and the vehicle power supply (B+).

Under normal operating conditions, the airbag squib circuit exhibits high resistance (2-5 Ω) and lacks continuity to power or ground.

A short to power causes the SRS ECU to detect an abnormally high circuit voltage (close to 12 V) and register a severe fault.

This condition may prevent the airbag from deploying correctly during a collision (as the short circuit bypasses the current) or, in extreme cases, cause unintended deployment (though a short circuit typically prevents rather than triggers ignition).

Repair this critical safety fault immediately.

The B1719-00 fault code on the Seal U indicates a high-severity SRS fault where the driver knee airbag circuit is shorted to vehicle power. This can stop the airbag working correctly and may create a safety risk. Common causes include damaged wiring insulation or water/terminal problems in the yellow airbag connector under the driver’s dash. Do not attempt DIY repairs; visit an authorised dealer immediately. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Worn or aged knee airbag wiring harness insulation contacts the dashboard metal frame or power wiring harness, causing a short circuit. This commonly occurs after driving through water, scraping the chassis, or prolonged driving on rough roads.
  • 2Internal terminal misalignment, backed-out terminals, or water ingress due to poor sealing in the yellow airbag connector (usually located under the driver's side dashboard or left of the steering column), causing a short circuit between the power terminal and the airbag signal wire.
  • 3Vehicle modifications (such as installing a dash cam, floor mat retaining clips, or modifying the audio system) pierce or crush the knee airbag wiring harness, damaging the insulation and causing a short circuit to power.
  • 4Insulation failure of the knee airbag module internal squib causes an internal short circuit to the power supply terminal.
  • 5SRS control unit internal monitoring circuit fault or false software report (less common, but rule out)
What To Do
  • 1
    Safe power down: Turn off the ignition switch, disconnect the 12V battery negative terminal, and wait at least 90 seconds (to ensure the SRS backup capacitor fully discharges). Do not connect or disconnect the airbag connector while powered on.
  • 2
    Inspection procedure: Remove the driver-side knee trim panel (Lower Panel). Locate the left knee airbag module (below the left side of the steering column) and the dedicated yellow connector. Visually inspect the wiring harness for abrasion, crushing, or modifications, and check the connector for water ingress, corrosion, or exposed pins.
  • 3
    Circuit measurement: With the airbag connector disconnected, use a high-impedance digital multimeter to measure the resistance between the wiring harness side (not the airbag side) and the power supply (B+). Normal resistance is infinite (OL). Continuity (low resistance) indicates the wiring harness is shorted to the power supply.
  • 4
    Section-by-section inspection: If the wiring harness is shorted, progressively open the corrugated conduit along the harness routing (typically through the instrument panel frame and body harness channel) to locate the damage. Closely inspect interference points at the steering column, clutch pedal (manual transmission), and instrument panel bracket.
  • 5
    Isolation check: If the wiring harness is normal, measure the resistance between the airbag module pins and from the pins to the housing to check for an internal short circuit within the module. If a short circuit exists, replace the airbag module.
  • 6
    Repair or replace: Repair the damaged wiring harness (using heat-shrink tubing and waterproof tape) or replace the damaged connector or airbag module. Never simply wrap the harness with tape; use the specified automotive wiring harness repair procedure.
  • 7
    System verification: Restore all connections and connect the battery. Clear the fault code using a dedicated diagnostic tool (such as BYD ED-400 or Launch X-431). Execute the SRS system self-check (verify the airbag warning light turns off after the 6-second self-check) and perform a road test to verify.
Real-World Cases
BYD DTC AI Analysis

Qin EV450: Aftermarket floor mats pierced the wiring harness, causing a short circuit.

✓
A 2018 Qin EV450 logged DTC B1719-00. Inspection found the owner had fitted full-surround floor mats. The retaining pins had pierced the knee airbag wiring harness beneath the dashboard, causing a short between the harness positive wire and the airbag circuit. The airbag warning light stayed on continuously, and the vehicle could not engage the high-voltage system (SRS faults trigger HV interlock on some models). Removed the floor mats, repaired the damaged harness by replacing a 15 cm section, and rewrapped it with waterproof insulation tape. Fault resolved.
BYD DTC AI Analysis

Water ingress and corrosion in Qin 100 connectors after wading

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2017 BYD Qin 100 developed DTC B1719-00 after wading through floodwater. Inspection revealed the driver-side knee airbag connector (above the pedal) had a deteriorated seal; water ingress caused electrolytic corrosion between the pins, creating a short to power. The airbag warning light illuminated intermittently after water exposure, sometimes clearing once dry. Cleaned the connector thoroughly with electronic cleaner, replaced the damaged pins and seal, and applied conductive grease. Fault resolved.
BYD DTC AI Analysis

Internal short circuit in airbag module igniter

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A Qin EV300 with 80,000 km logged DTC B1719-00. Wiring checks revealed no faults. After disconnecting the airbag module connector, we measured the harness side and found no short to power. However, measuring the knee airbag module itself, we found continuity between both pins and the module's metal casing, indicating the internal igniter insulation had broken down. Replaced the left knee airbag module (part number: G5A-5820500 or superseded version). Programming and matching cleared the fault. Caution: Dispose of the old airbag as hazardous waste.
BYD DTC AI Analysis

Dashboard wiring harness chafing against bracket

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2017 BYD Qin 80: Airbag warning light intermittently illuminated when driving on rough roads. Scanner showed intermittent fault code B1719-00. Inspection found untreated burrs on the dashboard frame; long-term vibration had worn through the knee airbag wiring harness insulation where it contacted the metal bracket, causing intermittent shorts to ground or power. Repair: Repaired the wiring harness, installed rubber protective sleeves and corrugated tubing at the interference points, and ground down the frame burrs. The fault has not returned.
BYD DTC AI Analysis

SRS control unit software false positive

✓
After routine servicing at a dealership, a Qin 100 suddenly logged DTC B1719-00. Checks of the wiring and airbag module found no issues. A review of repair history showed the vehicle had previously received an SRS software update. The cause was a software version compatibility issue triggering a false DTC. Solution: Flashed the SRS control unit to the latest software version (or rolled back to a stable version) and performed configuration coding. The fault code cleared and the airbag system resumed normal self-check operation.
Other Seal U Fault Codes
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.B110A02DTC B110A02 indicates the thermal management master control unit (HVAC ECU) or body control module (BCM) failed to receive valid CAN data frames from the PM2.5 air quality sensor over consecutive communication cycles (typically 500ms per cycle). The sensor typically mounts at the HVAC unit air inlet or behind the glove box and transmits real-time particulate concentration data (unit: μg/m³) to the HVAC controller via the CAN bus. The fault is essentially a communication link layer timeout. Potential causes include physical layer wiring faults, sensor power supply failures, sensor internal MCU lockup, or CAN network topology damage. Although this non-critical fault does not directly affect driving safety, it disables the intelligent air purification strategy and the automatic fresh air/recirculation switching function. In extreme cases, it triggers a thermal management system degraded mode, limiting compressor power or fixing the air flap position.B110BDTC B110B indicates a fault in the internal air pump (sampling pump) of the PM2.5 air quality detector. This pump draws cabin or outside air into the PM2.5 sensor detection chamber, enabling the laser scattering sensor to measure real-time particulate matter concentration. The air conditioning controller (or BCM) sets this DTC upon detecting an open or short circuit in the pump drive circuit, or abnormal current caused by a seized pump motor. This fault disables the "Green Clean" system, causes the instrument cluster air quality display to read abnormally or disappear, and disables the automatic fresh air/recirculation switching function. It does not affect the vehicle powertrain or core thermal management functions.B173712DTC B173712 indicates a short to power in the firing circuit of the right second-row side airbag module in the Supplemental Restraint System (SRS). Specifically, the "right second-row side airbag" typically refers to the side impact airbag located in the right B-pillar or the side of the right seat. The "12" suffix indicates a circuit short to battery positive (B+). This fault causes the following conditions: 1) The airbag may fail to ignite and deploy during a collision, resulting in a loss of side impact protection. 2) In extreme cases, unintended triggering may cause accidental airbag deployment. 3) The SRS control unit detects abnormally high circuit voltage (typically above 4.5V) and enters fault protection mode. This may disable the entire airbag system and continuously illuminate the instrument cluster airbag warning light.
Common problems reported for Seal U →Seal U overview →
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.