AU
B1750-00

This DTC indicates the SRS (Supplemental Restraint System) ECU cannot establish valid communication with the right rear side airbag module and detects an open circuit in the airbag circuit (resistance exceeds the normal 2-3Ω range, typically reading as infinite or >10Ω) — Seal U

Safety System

This DTC indicates the SRS (Supplemental Restraint System) ECU cannot establish valid communication with the right rear side airbag module and detects an open circuit in the airbag circuit (resistance exceeds the normal 2-3Ω range, typically reading as infinite or >10Ω).

This failure disables protection for the right rear occupant during a side impact and may trigger an SRS downgrade mode, affecting the coordinated deployment strategy of other airbags.

On certain vehicle configurations, incorrect vehicle coding (flashing high-spec software to a low-spec vehicle) can cause a false DTC.

4
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Loose or disconnected right rear seat side airbag connector, or oxidized terminals (common after frequent fore/aft seat adjustment or failure to reconnect after cleaning)
  • 2Internal open circuit or abnormal resistance in the airbag module (module aging, moisture, or electrostatic damage)
  • 3Wiring harness open circuit or chafing causing a short to ground or power (due to long-term harness bending and wear inside the seat slide rail, B-pillar, or door sill trim panel).
  • 4Vehicle hardware configuration does not match software (low-spec model lacks this airbag, but SRS ECU uses high-spec configuration).
  • 5Internal SRS ECU fault or software version defect (intermittent loss of communication or false warning)
What To Do
  • 1
    Safe power-down: Turn the power switch to OFF, disconnect the battery negative terminal, and wait at least 90 seconds to fully discharge the SRS system capacitors and prevent accidental airbag deployment during repair.
  • 2
    Visual inspection: Remove the right rear seat and side trim panel. Locate the airbag module connector (usually on the side of the seat backrest or below the B-pillar). Check for looseness, disconnection, water ingress, or terminal oxidation. Disconnect and reconnect the connector, confirming the locking tab fully engages.
  • 3
    Circuit measurement: Disconnect the airbag module connector. Use a multimeter to measure the harness terminal voltage to ground (must be <1V to rule out a short to power) and circuit continuity (resistance between the ECU and connector must be <2Ω). Measure the insulation resistance to ground (must be >10MΩ).
  • 4
    Replacement verification: Connect a known-good right rear side airbag module (or dedicated simulator). Restore power to ON, clear the fault code using the diagnostic tool, and wait 20 seconds to perform a self-test. If the fault code disappears, the original module has an internal fault.
  • 5
    Wiring harness repair: If the wiring harness has an open circuit, short circuit, or wear, repair the damaged wire (solder and insulate with heat-shrink tubing) or replace the wiring harness assembly. Install protective sleeves at the seat slide rail and B-pillar to prevent recurring wear.
  • 6
    System reset: Restore all connections, reconnect the battery, perform SRS system configuration coding (if replacing the ECU or module), clear fault codes, and perform a crash simulation test (using the diagnostic tool to execute the active test function). Confirm the warning light turns off and the system has no fault codes.
Real-World Cases
BYD DTC AI Analysis

Qin EV450 right rear seat adjustment caused connector to come loose

✓
2018 BYD Qin EV450. Owner reported the airbag warning light stayed on after large forward/backward movements of the right rear seat. Scanned with VDS2000 and retrieved DTC B1750-00. Removed the right rear seat side trim panel and found the airbag module connector (beneath the seat backrest) not fully latched, causing it to come loose from seat track movement. Reconnected firmly, verified the latch engaged, then secured the harness with cable ties so it wouldn’t move with the seat. Cleared the fault code – issue resolved.
Original source ↗
BYD DTC AI Analysis

Qin 100: Internal open circuit in right rear side airbag module

✓
2017 BYD Qin 100. After collision repair to the right rear door and replacement of the door panel, DTC B1750-00 appeared and could not be cleared. Inspected connectors: connections normal. Measured airbag module resistance: infinite (normal: 2–3 Ω), determined an internal open circuit in the module (likely caused by static electricity or improper handling during repair). Replaced the right rear seat side airbag module, performed SRS system configuration and coding matching with the diagnostic scanner. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Qin EV300 seat rail wear chafed through wiring harness, causing intermittent fault

✓
2017 BYD Qin EV300. SRS warning light illuminates intermittently. DTC B1750-00 sets intermittently. Rough roads easily trigger the fault. Found that at certain seat positions, the right rear seat rail pressed against and chafed the wiring harness, damaging the airbag circuit wire insulation and causing a short to earth. Repaired the damaged harness (rewrapped and fitted protective sleeving), rerouted the harness away from the seat rail movement range, and fitted a rubber sleeve at the interference point. Fault fully resolved.
BYD DTC AI Analysis

Incorrect software configuration on Qin 80 base model triggers false alarm.

✓
A 2017 BYD Qin 80 Comfort trim (no rear side airbags from factory) set DTC B1750-00 right after an SRS software update at the dealership. A configuration check revealed that the right rear side airbag was not physically installed; however, the SRS ECU had been incorrectly flashed with the high-spec software. The technician reflashed the ECU with the base model configuration codes using the dedicated diagnostic tool (VIN rematching and parameter configuration). The code cleared and the system returned to normal.
Other Seal U 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.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.
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.