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 U

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 U indicates an open circuit in the Passenger Airbag Cutoff Switch or its wiring, causing the SRS module to detect an invalid resistance signal. This medium severity issue may disable the front passenger airbag. Common causes include switch damage or connector corrosion. Visit an authorised dealer for repair. Typical repair cost data is available from 5 recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Front passenger airbag deactivation switch physically damaged or internal contacts oxidized, causing signal interruption.
  • 2Pin back-out, looseness, or corrosion between the switch and wiring harness connector, especially due to moisture in the front passenger footwell.
  • 3Open circuit, crush damage, or short to ground/power in the wiring harness from the switch to the SRS ECU, commonly resulting from improper harness routing after dashboard removal and installation.
  • 4SRS control module internal sampling circuit fault causing incorrect switch status detection.
  • 5Switch connector loosened after a minor vehicle collision or jolt that 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 other SRS-related fault codes.
  • 2
    Locate the front passenger airbag deactivation switch (typically located 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 battery negative terminal and wait at least 3 minutes to discharge residual power from the SRS system. Unplug the switch connector and use a multimeter to measure switch resistance in different positions (ON/OFF). Resistance must fall within the specified range (usually 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 to check for an open circuit (infinite resistance) or a short to ground/power. Focus on instrument panel frame pinch points 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 voltage waveform of the switch signal 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 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.