AU
B1717-00

This DTC indicates the SRS (Supplemental Restraint System) ECU detected an open circuit or disconnected condition in the left knee airbag module (Driver Knee Airbag Module) during self-diagnosis — Qin Plus

Safety System

This DTC indicates the SRS (Supplemental Restraint System) ECU detected an open circuit or disconnected condition in the left knee airbag module (Driver Knee Airbag Module) during self-diagnosis.

Specifically, when the SRS ECU sends a test signal to the left knee airbag igniter circuit, it fails to receive a normal circuit response or detects a circuit resistance exceeding the normal threshold (typically infinite or extremely high resistance).

Consequently, the left knee airbag may fail to deploy during a collision, resulting in a loss of lower limb protection for the driver.

Additionally, the SRS enters fail-safe mode and continuously illuminates the instrument cluster airbag warning light.

The system may also lock the deployment function of the entire airbag system, severely compromising passive safety performance.

The B1717-00 fault code on the Qin Plus indicates an open or disconnected circuit in the driver knee airbag module, which may stop the knee airbag from deploying and turn on the airbag warning light. This is a medium-severity safety issue. Common causes include a loose or damaged airbag connector or an open wiring harness between the SRS ECU and airbag. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
4
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Knee airbag module connector loose, not fully seated, or locking tab damaged, causing poor pin contact or complete disconnection.
  • 2Open circuit, short to ground, or short to power in the wiring harness between the SRS ECU and the left knee airbag module.
  • 3Left knee airbag module internal igniter open circuit or abnormal resistance (resistance too high or too low)
  • 4Oxidized, corroded, or backed-out connector pins causing increased contact resistance.
  • 5Improper airbag module installation or crushed and damaged wiring harness after vehicle accident repairs or instrument panel removal and installation.
What To Do
  • 1
    Safety preparation: Turn the power switch to OFF, disconnect the battery negative terminal, and wait at least 90 seconds to fully discharge the SRS capacitor.
  • 2
    Visual inspection: Remove the driver-side knee trim panel. Verify the left knee airbag module connector is fully seated. Confirm the retaining clip is intact and secure.
  • 3
    Circuit measurement: Use a multimeter to measure the harness resistance between the SRS ECU and the knee airbag module (should be less than 1Ω). Measure the harness resistance to ground (should be greater than 1MΩ) and voltage to ground (should be less than 1V).
  • 4
    Component replacement test: Disconnect the original airbag module, connect a known-good left knee airbag module (or simulated load), and read the fault code to determine if the module is faulty.
  • 5
    Connector handling: If pins are oxidized, clean them with electrical contact cleaner and apply conductive grease. If the locking tab is damaged, replace the connector or repair the wiring harness.
  • 6
    System reset: Reconnect all components, turn the power on, use the diagnostic tool to clear the fault code, wait 20 seconds, reread the codes, and verify B1717-00 does not return.
  • 7
    Function verification: Perform the SRS system self-check. Confirm the airbag warning lamp turns off after the self-check and the system returns to a normal state.
Real-World Cases
BYD DTC AI Analysis

Loose connector on left knee airbag causing 'not connected' fault

✓
A 2017 BYD Qin EV300's airbag warning light stayed on. Read DTC B1717-00. Found that during a cabin air filter replacement at an independent shop, removing and refitting the lower dash trim had loosened the left knee airbag connector. After firmly reconnecting the connector and confirming the retaining clip was fully seated, cleared the DTC and the system returned to normal.
Original source ↗
BYD DTC AI Analysis

Knee airbag module damaged after accident repair

✓
After front collision repair on a 2017 Qin 100, the SRS warning light stayed on. The diagnostic scanner showed DTC B1717-00. Inspection found the left knee airbag module had not deployed, but impact from the accident caused an open circuit in the internal igniter. The module showed infinite resistance. Replacing the left knee airbag module resolved the fault.
Original source ↗
BYD DTC AI Analysis

Wiring harness chafing caused intermittent open circuit

✓
A 2018 BYD Qin EV450 had an intermittent airbag warning light; fault code B1717-00 would come and go. I found the driver's side knee area wiring harness had chafed through from prolonged steering movement, damaging the insulation and partially breaking some internal copper wires. I repaired the harness and fitted an anti-chafe sleeve, which completely resolved the fault.
BYD DTC AI Analysis

Oxidised connector pins causing poor contact

✓
A high-mileage Qin 80 logged DTC B1717-00 after use in humid conditions. Disassembly inspection found green oxidation on the left knee airbag connector pins, increasing contact resistance (measured 15 Ω; normal: <1 Ω). Cleaned the pins and applied conductive grease. Resistance returned to normal, then cleared the fault code.
Original source ↗
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.