AU
B1719

DTC B1719 indicates a short to B+ in the Driver Side Knee Airbag squib circuit — Seal U

Safety System

DTC B1719 indicates a short to B+ in the Driver Side Knee Airbag squib circuit.

In the SRS (Supplemental Restraint System) architecture, the knee airbag squib is a low-value resistor (standard value 2.0 ± 0.3 Ω).

Under normal conditions, the airbag ECU triggers the squib by controlling the ground circuit.

When the diagnostic system detects the circuit voltage continuously exceeding the threshold (typically above 4.5V, approaching the 12V battery voltage), it identifies a short to power.

This fault results in the following: 1) The ECU actively disables the airbag circuit, preventing deployment during a collision and resulting in a loss of driver leg protection. 2) A potential safety risk exists; in extreme cases, circuit abnormalities may cause unintended airbag deployment. 3) The SRS enters fail-safe mode and continuously illuminates the instrument cluster airbag warning light.

Inspect for damaged wiring harness insulation, misaligned connector terminals, electrolytic short circuits caused by fluid ingress, and internal short circuits within the airbag module squib.

The B1719 fault code on the Seal U indicates a short to battery power in the driver side knee airbag squib circuit. This is a high-severity SRS fault that can disable the knee airbag and keep the airbag warning light on. Common causes include damaged or chafed wiring near the dashboard or steering column, or an internal squib fault from moisture or aging. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Prolonged chafing of the knee airbag wiring harness against the instrument panel metal frame or steering column edge damages the insulation, causing a short to the constant power supply wire.
  • 2Manufacturing defects, moisture ingress, or aging cause an internal short circuit in the knee airbag assembly igniter (squib), resulting in an abnormally low resistance value.
  • 3Terminals in the yellow dedicated SRS connector under the driver's dashboard are bent, backed out, or improperly seated, and contact an adjacent power pin (such as constant 12V).
  • 4Vehicle wading, interior deep cleaning, or air conditioning condensate leakage causes liquid to enter the connector, resulting in an electrolytic short circuit between terminals.
  • 5Improperly secured wiring harness after accident repairs or modifications, causing the steering column universal joint, pedal mechanism, or seat rail to pinch the harness, resulting in insulation damage and a short circuit.
What To Do
  • 1
    Safe power-down: Turn off the ignition, disconnect the negative battery cable, and wait at least 3 minutes to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 2
    Visual inspection: Remove the driver-side lower dashboard trim panel (knee bolster) and inspect the knee airbag yellow 2-pin connector and wiring harness for damage, burn marks, signs of water ingress, or modification pinch marks.
  • 3
    Resistance measurement: Disconnect the airbag connector. Use a digital multimeter to measure the resistance between the two terminals of the knee airbag inflator. The standard value is 2.0±0.3 Ω. If the resistance is below 1.0 Ω or reads 0, the airbag has an internal short circuit. Replace the assembly.
  • 4
    Voltage check: Reconnect the battery (leave the airbag connector disconnected). Back-probe the harness-side connector terminal to measure voltage. The normal reading is close to 0V (ECU internal pull-down resistor). A 12V battery voltage reading confirms a short to power.
  • 5
    Harness continuity check: Disconnect the airbag ECU connector. Check the wiring harness between the knee airbag connector and the ECU for a short to the power supply line (constant B+). Focus inspection on the dashboard harness tie points and pass-through holes.
  • 6
    Insulation repair: If the wiring harness is damaged, wrap the damaged area with double-layer heat-shrink tubing. Reroute the harness to avoid moving parts (such as the steering column, accelerator pedal, and seat rails).
  • 7
    Component replacement: If diagnostics confirm an internal short circuit in the airbag, replace the driver knee airbag assembly (Note: Do not measure resistance before installing the new part to prevent static current from triggering accidental deployment).
  • 8
    System reset: After installation, reconnect the battery. Use VDS or a dedicated diagnostic tool to clear the fault code. Perform the SRS system self-check (approximately 3-5 ignition cycles). Confirm B1719 does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI Analysis

Modified seat rails crushed the knee airbag wiring harness on a Song Pro, causing a short circuit

✓
The SRS warning light stayed on. VDS read DTC B1719 (left knee airbag short to power). The owner told us they had recently retrofitted electric seats. We removed the lower dash panel and found the seat rail mounting bolt had punctured the knee airbag wiring harness, damaging the insulation and shorting it to constant power. We measured 12V at the knee airbag connector to ground, with only 0.5 Ω resistance. We repaired the damaged harness using double-layer heat shrink tubing, rerouted the wiring clear of the seat track travel path, replaced the damaged yellow SRS connector, and cleared the fault codes. After clearing the codes, the system passed self-diagnosis. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Water ingress during interior cleaning caused knee airbag connector oxidation and short circuit on Qin Plus DM-i

✓
After starting the vehicle, the dashboard displayed 'Check SRS System' and the airbag warning light came on. The scan tool read DTC B1719. The owner said they had done a deep interior cleaning the previous day, and a large amount of liquid flowed into the driver-side floor. Removed the knee airbag connector located under the instrument panel to the left of the steering column. Pins showed severe oxidation and green copper corrosion. Measured the resistance between the signal wire and power pin and found it abnormal. Repair: Cleaned the connector terminals thoroughly with electronic cleaner, applied conductive grease to prevent corrosion, replaced the waterproof connector retaining clip to ensure a proper seal, reconnected the connector, cleared the fault code, and the system returned to normal.
Original source ↗
BYD DTC AI Analysis

Tang DM: knee airbag harness root fatigue fracture, intermittent short to power

✓
The SRS light illuminated intermittently on rough roads but stayed off on smooth ones. The diagnostic tool displayed intermittent DTC B1719. A static measurement showed the knee airbag resistance was normal (2.1 Ω), but shaking the wiring harness below the dashboard caused the resistance to jump to infinity, and a 12V reading occasionally appeared. Disassembly revealed that the knee airbag harness had broken internal copper wires at the point where they exit the dashboard frame due to long-term vibration. The broken ends occasionally contacted adjacent power wires during vibration. Solution: Replaced the knee airbag wiring harness assembly (including the connector), re-secured the harness with enough slack to stay clear of the steering column travel range, and road tested 50 km with no fault recurrence.
Original source ↗
BYD DTC AI Analysis

Yuan Pro: After accident repair, knee airbag connector locking tab broken, poor contact

✓
Vehicle repaired after front collision (dashboard replaced). Post-repair, airbag warning light stayed on, storing DTC B1719. Inspected the newly replaced knee airbag and SRS ECU. Found the knee airbag connector appeared plugged in, but its internal locking tab had broken in the accident, causing the terminal to back out and contact the adjacent constant-power pin, creating a short circuit. Also found poor ground at the SRS ECU earth point due to residual paint. Repair: Sanded the ECU earth point to achieve ground resistance below 1 Ω. Replaced the knee airbag connector (repair kit). Re-performed SRS configuration write and 'collision output clear' procedures. Fault fully resolved.
Original source ↗
BYD DTC AI Analysis

Han EV knee airbag internal igniter short circuit caused abnormal resistance.

✓
The vehicle had no collision history, but the SRS light came on suddenly with DTC B1719. After disconnecting the knee airbag connector, we checked the harness side: no short to power (0V). The airbag assembly side (igniter) resistance measured 0.6 Ω, well below the standard 2.0 Ω, indicating an internal short in the knee airbag igniter. Further inspection found a tiny crack in the airbag housing sealant, likely allowing moisture to cause the short. We replaced the driver's side knee airbag assembly (confirmed the part number matched the vehicle configuration), then used VDS for ECU coding and matching, cleared the fault codes, and ran the system self-test. The airbag light went out.
Original source ↗
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.