AU
B175B1A

DTC B175B1A indicates the right rear side airbag igniter circuit resistance falls below the normal ECU threshold (typically below 1 — Seal 6 EV

Safety System

DTC B175B1A indicates the right rear side airbag igniter circuit resistance falls below the normal ECU threshold (typically below 1.0 Ω).

In the BYD SRS (Supplemental Restraint System), standard airbag igniter resistance is generally 2.0–3.0 Ω.

If the ECU continuously detects abnormally low circuit resistance, it logs a short circuit fault (indicating a possible short to ground or internal igniter short circuit).

This fault causes the following: 1) The airbag may fail to deploy during a collision, resulting in a loss of side protection. 2) The airbag may deploy unexpectedly in extreme cases. 3) The SRS enters fail-safe mode and illuminates the airbag warning light.

Common causes include wiring harness wear, connector water ingress, or an internal airbag module short circuit.

The B175B1A fault code on the Seal 6 EV indicates the right rear side airbag igniter circuit has resistance below the ECU’s normal limit, suggesting a possible short circuit. This is a medium-severity SRS fault that may affect side airbag operation and turn on the airbag warning light. Common causes include an internal airbag module short or worn/pinched wiring. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
5
Causes
Likely Causes — Seal 6 EV
  • 1Right rear side airbag module internal igniter short circuit (internal bridge wire short circuit or moisture ingress)
  • 2Wiring harness wear causing a short to ground (commonly pinched or worn near the seat rail or inside the C-pillar trim)
  • 3Connector water ingress or terminal corrosion (vehicle wading, rear floor water ingress, or moisture entering the connector after a car wash)
  • 4SRS control unit internal detection circuit fault (abnormal ECU sampling resistor or detection chip)
  • 5Wiring harness damaged during modification or repair (e.g., piercing the harness when installing seat heating or retrofitting leather seats).
What To Do
  • 1
    Use the BYD VDS diagnostic tool to read fault codes, confirm B175B1A is a current fault, record freeze frame data, and check for accompanying SRS fault codes (e.g., B175C).
  • 2
    Perform the safe power-down procedure: disconnect the battery negative terminal and wait at least 3 minutes to ensure the SRS capacitor discharges completely to prevent accidental airbag deployment.
  • 3
    Inspect the right rear side airbag wiring harness connector (usually located below the C-pillar or on the side of the rear seat) for looseness, backed-out pins, water ingress, or white corrosion. Clean the connector and apply conductive grease if necessary.
  • 4
    Disconnect the SRS ECU connector (located under the center console or in the front compartment). Use a multimeter to measure the resistance at the right rear side airbag wiring harness terminal. Normal resistance is 2-3 Ω. A reading close to 0 Ω or <1 Ω confirms a short circuit in the wiring.
  • 5
    Inspect the wiring harness in sections: disconnect and measure the circuit from the ECU to the airbag. Focus the inspection on the wiring harness at the seat rail mounting points, inside the B-pillar trim, and inside the C-pillar trim for wear, damaged insulation, or crushing deformation.
  • 6
    Remove the right rear side airbag module (requires removing the C-pillar trim panel or seat backrest) and directly measure the resistance across the two terminals of the airbag module. If the resistance is <1Ω, replace the airbag module.
  • 7
    Repair the short circuit (tape the wiring harness, replace the connector) or replace the faulty airbag module. Ensure all connections are secure to prevent poor contact.
  • 8
    Reconnect the battery, clear the fault code, and perform the SRS system self-test (turn the ignition switch ON and observe if the airbag warning light turns off after 6 seconds). Perform a road test to verify.
Real-World Cases
BYD DTC AI Analysis

Steering wheel cruise control switch failure (B17 series reference)

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Symptoms: Steering wheel cruise control switch completely inoperative. Pressing the 'Set' button gets no response, and the instrument cluster shows no cruise setting information. Some owners reported abnormal instrument cluster warnings. Diagnosis: The owner replaced the steering wheel cruise control switch assembly, instrument panel relay assembly, and instrument cluster assembly one by one, but the fault remained. Technicians suspected either a faulty Set button or an internal break in the steering wheel clock spring wiring, blocking the switch signal from reaching the BCM. Solution: The forum post did not record a final confirmed solution. Follow-up posts suggested checking the steering wheel clock spring ribbon cable, multifunction switch connectors, and Body Control Module (BCM) software version. Note: Although this is not a direct B175B1A case, it demonstrates the wiring troubleshooting approach for B17-series fault codes.
Original source ↗
BYD DTC AI Analysis

VCU communication interrupted (pin backed out)

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**Symptoms:** Scan tool cannot communicate with the Vehicle Control Unit (VBU/VCU). Some electronic functions failed and the instrument cluster may display "Check Power System" or related warning lights. **Diagnosis:** Technician checked power, ground and CAN bus communication. Found pins G09-14/15 (GJK14 harness junction) backed out, breaking the communication signal. Confirmed fuse F4/9 had not blown, ruling out power supply problems. **Repair:** Fixed the backed-out pins in the wiring harness connector and re-secured the terminals for proper contact. Cleared DTCs with the scan tool. VCU communication returned to normal. **Note:** This case shows a system failure caused by wiring harness connector pin retraction in BYD vehicles. Useful reference for troubleshooting poor harness connections in SRS systems.
Original source ↗
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.