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 — Atto 8

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 Atto 8 indicates an open circuit in the passenger airbag cutoff switch or its wiring, causing the SRS module to lose the resistance signal and potentially disable the front passenger airbag or trigger the warning light. Severity is medium. Common causes include physical switch damage, oxidized contacts, or wiring connector corrosion. An authorised dealer must diagnose and repair the fault. Typical repair cost data is available based on 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Physical damage to the front passenger airbag deactivation switch or oxidized internal contacts, causing signal interruption.
  • 2Pin back-out, looseness, or corrosion between the switch and wiring harness connector, especially under damp conditions in the front passenger footwell.
  • 3Open circuit, crushed or damaged wires, or short circuit to ground or power in the wiring harness from the switch to the SRS ECU. Improper harness routing after dashboard removal and installation commonly causes this.
  • 4SRS control module internal sampling circuit fault causing incorrect switch status detection.
  • 5Switch connector loose or disconnected after a minor collision or bump 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 current (Active). Record the freeze frame data and check for 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 inserted, 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. Unplug the switch connector. Use a multimeter to measure the switch resistance in different positions (ON/OFF). The resistance should fall within the specified range (usually 2-5kΩ or continuity). Replace the switch if the resistance is infinite.
  • 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 the wiring pinch points on 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 measure the switch signal voltage waveform from the ECU 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 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 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.