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+) — Atto 3

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 Atto 3 indicates a high-severity SRS fault where the driver knee airbag circuit is shorted to battery power. This can stop the airbag from working correctly and needs urgent attention. Common causes include damaged wiring insulation near the dashboard or a faulty/wet yellow airbag connector. The recommended fix is to visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 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, underbody scraping, or prolonged driving on rough roads.
  • 2Misaligned pins, backed-out pins, or water ingress from poor sealing inside the yellow airbag connector (usually located under the driver's side dashboard or left of the steering column) cause a short circuit between the power pin and the airbag signal wire.
  • 3Vehicle modifications (such as installing a dash cam or floor mat retaining clips, or modifying the audio system) pierce or crush the knee airbag wiring harness, damaging the insulation and causing a short to power.
  • 4Knee airbag module internal squib insulation failure causes an internal short circuit to the power supply terminal.
  • 5Internal monitoring circuit fault in the SRS control unit, or software false positive (less common, but rule out)
What To Do
  • 1
    Safe power-off: Turn off the ignition switch, disconnect the 12V battery negative terminal, and wait at least 90 seconds (to ensure the SRS backup capacitor discharges completely). Do not connect or disconnect the airbag connector while powered on.
  • 2
    Location and inspection: Remove the driver-side knee trim panel (Lower Panel) and 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 wear, crushing, or modification, 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 infinity (OL). Continuity (low resistance) indicates the wiring harness is shorted to the power supply.
  • 4
    Section-by-section troubleshooting: If the wiring harness has a short circuit, progressively open the corrugated conduit along the routing path (typically through the instrument panel frame and body harness channel) to locate the damage. Focus on interference points with 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 terminals and from the terminals to the housing to check for an internal module short circuit (if shorted, replace the airbag module).
  • 6
    Repair/Replace: Repair damaged wiring harnesses using heat-shrink tubing and waterproof tape. Replace damaged connectors or the airbag module. Never simply wrap wires 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). Perform an SRS system self-check (verify the airbag warning light turns off after completing the 6-second self-check). 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 Atto 3 Fault Codes
P0AA6Hybrid Battery Voltage System Isolation FaultB1108For 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.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.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.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.
Common problems reported for Atto 3 →Atto 3 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.