AU
B1680-00

DTC B1680-00 indicates the SRS (Supplemental Restraint System) control module detected an open circuit in the Passenger Airbag Cutoff Switch or its related wiring — Qin Plus

Safety System

DTC B1680-00 indicates the SRS (Supplemental Restraint System) control module detected an open circuit in the Passenger Airbag Cutoff Switch or its related wiring.

This switch, typically located in the center console or glovebox area, manually disables the airbag when a child seat occupies the front passenger seat.

The fault occurs because the SRS ECU fails to detect a valid resistance signal from the switch during the self-check cycle (normally a specific resistance range, such as 2-5kΩ, or a ground signal), triggering a level-two safety warning.

This condition may forcibly disable the front passenger airbag or place it in an uncertain state, severely compromising the occupant protection strategy during a collision.

The fault also illuminates the SRS warning light on the instrument cluster and prevents the vehicle from passing a safety inspection.

The B1680-00 fault code on the Qin Plus indicates an open circuit in the passenger airbag cutoff switch or its wiring, causing the SRS warning light to illuminate and potentially disabling the front passenger airbag. Severity is medium. Common causes include switch damage, corroded contacts, or loose connections. Visit an authorised dealer for inspection and repair. Typical repair cost data is available from 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Physical damage to the front passenger airbag deactivation switch or oxidized internal contacts interrupts the signal.
  • 2Pin back-out, loose connections, or corrosion between the switch and wiring harness connector, especially with moisture in the front passenger footwell.
  • 3Open circuit, crush damage, or short to ground/power in the wiring harness between the switch and the SRS ECU. Improper harness routing after dashboard removal and installation commonly causes this.
  • 4Internal fault in the SRS control module sampling circuit causing incorrect switch status detection.
  • 5A minor vehicle collision or jolt loosened the switch connector but did not trigger the crash sensor.
What To Do
  • 1
    Connect the BYD dedicated diagnostic tool (VDS or ED-400). Read all fault codes and confirm B1680-00 is a current fault (Active). Record the freeze frame data and check for accompanying SRS-related fault codes.
  • 2
    Locate the front passenger airbag deactivation switch (Qin series: usually located on the right side of the center console or inside the glovebox). Visually inspect the switch exterior for damage, verify full connector insertion, and confirm the locking tab is intact.
  • 3
    Disconnect the battery negative terminal and wait at least 3 minutes to discharge residual power in the SRS system. Disconnect the switch connector. Use a multimeter to measure switch resistance at different positions (ON/OFF). Resistance must be within the specified range (typically 2-5 kΩ or continuity). If resistance is infinite, replace the switch.
  • 4
    Measure wiring harness continuity between the switch-side connector and the SRS ECU. Check for an open circuit (infinite resistance) or a short to ground/power. Focus on wire pinch points at the instrument panel crossmember and the grommet where the floor harness passes through the firewall.
  • 5
    If the wiring harness is normal, check the SRS ECU connector pins for oxidation or deformation. If necessary, use an oscilloscope to test the switch signal voltage waveform sent by the ECU to confirm the ECU sampling circuit is normal. If abnormal, replace the SRS control module.
  • 6
    After repairing or replacing the faulty component, reconnect all connectors and the battery. Use the diagnostic tool to clear the fault code and perform the SRS system self-check procedure. Confirm B1680-00 becomes a history fault or clears. Perform a front passenger airbag simulated deployment test (using the special load tool) to verify switch function.
Real-World Cases
BYD DTC AI Analysis

Qin EV300 SRS light on after dashboard modification

✓
When the vehicle arrived, the instrument cluster displayed a constant airbag warning light. The customer reported the fault appeared after an external modification shop installed a centre infotainment screen. Using VDS, we read current fault code B1680-00. We found the passenger airbag switch wiring harness connector was not fully seated. During the retrofit, pulling when removing the dashboard caused the connector to loosen and the locking tab to break. We reconnected the connector and secured it with cable ties. After clearing the fault code, the SRS system returned to normal. We test drove the vehicle for 30 kilometres without the fault reoccurring.
BYD DTC AI Analysis

BYD Qin 100 passenger airbag switch failed after wading.

✓
A 2017 Qin 100's SRS warning light came on after driving through deep water during heavy rain. The scan tool showed codes B1680-00 and B167F-00 (passenger airbag circuit low resistance). Inspection found a poorly sealed wiring harness grommet on the passenger floor, allowing water to enter and corrode the switch connector pins. Disassembly revealed internal oxidation of the switch and green copper corrosion on the wiring terminals. Replaced the passenger airbag switch assembly, treated the corroded wiring sections, and re-sealed the waterproofing. Fault resolved. Recommend checking the vehicle's drain holes for blockages.
BYD DTC AI Analysis

Intermittent SRS fault on BYD Qin EV450

✓
The customer reported the SRS warning light occasionally illuminating, clearing after cycling the ignition. Scanned history DTCs and found multiple B1680-00 entries. Wiggling the passenger footwell wiring harness reproduced the fault. Close inspection revealed fretting wear on the switch connector pins, causing unstable contact resistance (normal <1Ω, faulty >10Ω). Replaced the wiring harness connector, adjusted pin tension, applied conductive grease to the contact surfaces, and conducted a continuous rough road test for 2 hours. The fault did not reappear; repair confirmed.
BYD DTC AI Analysis

Airbag control module false positive

✓
No accident history. SRS light suddenly illuminated, only DTC B1680-00 set. Measured switch and harness: both normal, resistance values meet workshop manual spec (3.2kΩ). Suspected internal sampling circuit fault in SRS ECU. Attempted software update (V1.2 to V1.4), fault persisted. Replaced SRS module with identical unit, performed coding. Fault code cleared and did not return. Testing found original ECU had damaged internal A/D converter chip.
BYD DTC AI Analysis

Passenger airbag switch internal mechanical sticking

✓
During routine servicing, found the SRS warning light on with fault code B1680-00. Inspection revealed the customer had left the passenger airbag disable switch (inside the glovebox) in the OFF position for an extended period and never toggled it. Disassembled the switch and found the contact points of the internal slider mechanism had oxidised and seized due to long-term inactivity, failing to produce a valid resistance signal. Cleaned and lubricated the internal switch contacts, demonstrated correct usage to the customer (advising periodic toggling to prevent oxidation), rectified the fault, and avoided unnecessary replacement.
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.