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 — Seal 6 EV

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 Seal 6 EV indicates an open circuit in the Passenger Airbag Cutoff Switch or its wiring, detected by the SRS control module. This medium-severity fault may disable the front passenger airbag and illuminate the SRS warning light. Common causes include physical damage to the switch, oxidized contacts, or connector corrosion. Visiting an authorised dealer is recommended. Typical repair cost data is available based on 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Physical damage to the front passenger airbag deactivation switch or oxidized internal contacts causing a signal interruption.
  • 2Pin back-out, looseness, or corrosion between the switch and wiring harness connector, especially after moisture exposure in the front passenger footwell.
  • 3Wiring harness from the switch to the SRS ECU has an open circuit, crush damage, or short to ground/power, commonly resulting from improper harness routing after dashboard removal and installation.
  • 4Internal fault in the SRS control module sampling circuit causes incorrect switch status detection.
  • 5Switch connector loosened after a minor collision or jolt without triggering 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 other accompanying SRS-related fault codes.
  • 2
    Locate the front passenger airbag deactivation switch (typically on the right side of the center console or inside the glove box on Qin series models). Visually inspect the switch exterior for damage. Verify the connector is fully seated and confirm the locking tab is intact.
  • 3
    Disconnect the 12V battery negative terminal and wait at least 3 minutes to discharge residual power in the SRS system. Unplug the switch connector. Use a multimeter to measure switch resistance in the ON and OFF positions. 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 harness connector and the SRS ECU. Check for an open circuit (infinite resistance) or a short to ground or 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, inspect the SRS ECU connector pins for oxidation or deformation. If necessary, use an oscilloscope to test the ECU switch signal voltage waveform to verify 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. Perform the SRS system self-check procedure and confirm B1680-00 becomes a history fault or clears. Perform a front passenger airbag simulated deployment test (using the dedicated 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 Seal 6 EV 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.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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.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 Seal 6 EV →Seal 6 EV 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.