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+) — Qin Plus

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 Qin Plus indicates a high-severity SRS fault: a short to battery power in the driver knee airbag squib circuit. This can prevent correct airbag deployment and needs immediate attention. Common causes include damaged or worn wiring insulation, water ingress, or poor pin contact in the yellow airbag connector. Do not attempt DIY repairs; visit an authorised dealer. Typical repair cost data is available from recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 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 pin misalignment, backed-out pins, 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 pin 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 harness insulation and causing a short to power.
  • 4Internal squib insulation failure in the knee airbag module causes an internal short circuit to the power supply terminal.
  • 5SRS control unit internal monitoring circuit fault or software false positive (less common, but rule this 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 discharges fully). Do not connect or disconnect the airbag connector while powered on.
  • 2
    Location and inspection: 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 modification. 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 (non-airbag side) and the power supply (B+). Normal resistance is infinity (OL). Continuity (low resistance) indicates the wiring harness is shorted to the power supply.
  • 4
    Section-by-section troubleshooting: If a wiring harness short circuit occurs, peel back the corrugated conduit step-by-step along the wiring route (typically routed 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 module short circuit (replace the airbag module if shorted).
  • 6
    Repair or replace: Repair the damaged wiring harness (using heat-shrink tubing and waterproof tape) and replace damaged connectors or the airbag module. Never simply wrap wires with electrical tape; use dedicated automotive wiring harness repair procedures.
  • 7
    System verification: Restore all connections and connect the battery. Use a dedicated diagnostic tool (such as BYD ED-400 or Launch X-431) to clear the fault code. Perform the SRS system self-test (verify the airbag warning light turns off after the 6-second self-test). 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.

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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

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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 Qin Plus 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.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.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.B173A1ADTC B173A1A indicates the right middle-row side airbag (typically located on the side of the right second-row seat or inside the C-pillar trim panel) igniter circuit resistance measures 0 Ω. In the Supplemental Restraint System (SRS), normal airbag igniter resistance ranges between 2.0 and 5.0 Ω. A resistance of 0 Ω indicates a short to ground or a short between circuit wires, preventing the Airbag Control Unit (ACU) from establishing a normal monitoring circuit. This safety-critical fault prevents the airbag from deploying during a collision, continuously illuminates the instrument panel SRS warning lamp, and may force the entire airbag system into fail-safe mode.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Qin Plus →Qin Plus 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.