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 8

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 8 indicates a high-severity SRS fault where the driver knee airbag squib circuit may be shorted to battery power. This can stop the airbag from working correctly in a crash and needs immediate attention. Common causes include damaged wiring insulation or water ingress/misaligned pins in the yellow airbag connector. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 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 underbody, or prolonged driving on rough roads.
  • 2Misaligned pins, backed-out pins, or water ingress due to poor sealing inside the yellow airbag connector (usually located under the driver 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, floor mat retaining clips, or audio system upgrades) pierce or crush the knee airbag wiring harness, causing insulation damage and a short 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 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 completely discharge the SRS backup capacitor). Do not connect or disconnect the airbag connector while powered on.
  • 2
    Inspection procedure: 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 signs of abrasion, crushing, or modification, and 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 a wiring harness short to the power supply.
  • 4
    Section-by-section inspection: If the harness is shorted, progressively peel back the corrugated conduit along the routing path (typically through the dashboard frame and body harness channels) to locate the damage. Focus on interference points at the steering column, clutch pedal (manual transmission), and dashboard 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, 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. 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-check (verify the airbag warning lamp turns off after the 6-second self-check). Conduct 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 8 Fault Codes
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.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.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.