AU
B175A

DTC B175A indicates the Right Rear Side Airbag ignition circuit resistance measures 0Ω, indicating a short to ground in the airbag circuit or an internal short circuit in the airbag module — Seal 6 EV

Safety System

DTC B175A indicates the Right Rear Side Airbag ignition circuit resistance measures 0Ω, indicating a short to ground in the airbag circuit or an internal short circuit in the airbag module.

Normal airbag inflator resistance ranges between 1.5 and 3.5 ohms (typically 2.0-2.8Ω).

When the SRS control module detects a resistance of 0Ω, it identifies a circuit short fault, immediately disables airbag deployment, and illuminates the instrument panel airbag fault warning lamp.

Due to this fault, the Right Rear Side Airbag may fail to inflate and deploy during a side impact, severely compromising occupant protection.

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

The B175A fault code on the Seal 6 EV indicates a short to ground in the right rear side airbag ignition circuit, with resistance measured at 0Ω. This is a medium-severity SRS fault because the airbag may not deploy in a side impact. Common causes include chafed wiring under the right rear seat or water ingress in the airbag connector. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
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Cases Logged
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Causes
Likely Causes — Seal 6 EV
  • 1Short to ground caused by chafed SRS wiring harness under the right rear seat: Seat sliding or height adjustments cause the yellow SRS wiring harness under the seat to rub against the metal slide rail or spring. Damaged insulation allows the exposed copper wire to directly contact the vehicle body ground.
  • 2Water ingress into the airbag connector or short circuit from bent pins: The right rear side airbag connector mounts on the side of the seat backrest or inside the C-pillar trim panel. Driving through water, improper car washing, or rainy weather easily causes water ingress, shorting the pins. Disconnecting and reconnecting the connector during seat repairs can also bend the pins, causing them to make contact.
  • 3Airbag module (gas generator) internal short circuit: A short circuit in the airbag igniter bridge wire or moisture in the pyrotechnic charge causes an abnormal drop in resistance. This condition is rare but requires replacing the entire airbag module.
  • 4SRS control module internal detection circuit fault: A damaged internal resistance detection circuit in the control module triggers a false short circuit fault, while the actual wiring and airbag are normal.
  • 5Wiring harness incorrectly secured after seat removal and installation: After repairing the seat trim or heating pad, failing to properly clip the SRS wiring harness into the retaining slot allows the seat frame to pinch the harness, causing a short circuit.
What To Do
  • 1
    Safety Preparation and Fault Confirmation: Disconnect the 12V battery negative terminal and wait at least 3 minutes. Use the BYD VDS dedicated diagnostic tool or Launch X431 to confirm DTC B175A. Check the resistance value in the freeze frame data (should display 0.0Ω). Check for accompanying SRS fault codes (such as B175B left rear side airbag fault).
  • 2
    Visually inspect the connector: Remove the right rear seat backrest side trim panel or lower C-pillar trim panel. Locate the yellow SRS wiring harness connector (usually with a double-locking mechanism). Inspect the inside of the connector for water stains, oxidation, corrosion, or bent/deformed pins. Clean with electrical contact cleaner and blow dry.
  • 3
    Harness continuity test: Disconnect the airbag connector and use a multimeter to measure the resistance between the harness side (body side) and body ground. The reading should be infinity (OL). A reading of 0 Ω or close to 0 Ω indicates a short to ground in the harness; continue troubleshooting.
  • 4
    Detailed under-seat wiring harness inspection: Remove the right rear seat assembly and fully open the under-seat wiring harness protective sleeve. Inspect the contact points between the wiring harness and the seat slide rails, springs, and metal brackets for insulation wear, cuts, or indentations. Repair any damage using heat-shrink tubing and waterproof tape. Reroute the wiring harness and secure it with cable ties to prevent interference with moving parts.
  • 5
    Airbag module resistance measurement: Use a dedicated airbag resistance measuring tool (or high-impedance multimeter) to measure the resistance of the airbag assembly (gas generator). The normal range is 1.5-3.5Ω. A reading of 0Ω or near 0Ω indicates an internal short circuit in the airbag module. Replace the right rear side airbag module. (Note: Disconnect the airbag power supply before measuring and use the dedicated resistance measurement mode to prevent accidental deployment.)
  • 6
    SRS control module verification: If the wiring harness and airbag module test normal, suspect a faulty SRS control module. Inspect the control module connector (usually located under the centre console or behind the centre armrest box) for looseness. Use an oscilloscope to check the diagnostic signal waveform output from the control module. If necessary, replace and recode the SRS control module.
  • 7
    System reset and verification: After completing repairs, reconnect all connectors (ensure an audible locking click), connect the battery, and clear the fault codes. Turn the ignition switch to the ON position and observe the airbag warning light on the instrument cluster: it should turn off after 6 seconds. Use a diagnostic tool to read the data stream and confirm the right rear side airbag resistance is within the normal range (1.5-3.5Ω). Finally, perform a seat fore-and-aft sliding test to verify there is no wiring harness interference.
Real-World Cases
BYD DTC AI Analysis

Worn right rear seat wiring harness caused B175A in BYD Tang DM

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Vehicle: 2021 Tang DM. Symptom: Instrument panel airbag warning light stayed on constantly. Read DTC B175A (right rear side airbag resistance: 0Ω). Diagnosis: Removed the right rear seat and found the yellow SRS wiring harness sheath underneath had been cut by the seat slide rail edge, with two internal wires exposed and touching the metal rail to create a short to ground. This line supplies the right rear side airbag. Repair: Cut out the damaged harness section, re-soldered the wires and insulated them with heat-shrink tubing. Rerouted the harness, added protective sleeving and securing clips at wear-prone points, and ensured the harness maintains at least 10mm clearance from the rail. After clearing the DTC, the airbag light went out and the data stream showed resistance had returned to 2.3Ω.
Original source ↗
BYD DTC AI Analysis

BYD Song MAX B175A Fault Code Repair After Water Ingress

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Vehicle: 2019 BYD Song MAX. Symptom: After driving through water, the instrument cluster displayed an airbag fault. The scanner read DTC B175A (right rear side airbag short circuit). Diagnosis: Inspected the airbag connector behind the right rear C-pillar trim and found obvious water staining and green corrosion inside, with a micro-short between pins caused by electrolytic corrosion. The C-pillar seal had degraded, letting water soak the connector during the water crossing. Repair: Cleaned the connector pins with electrical contact cleaner and fine sandpaper, dried them with compressed air, and applied contact protectant. Replaced the C-pillar seal to prevent recurrence. The airbag module was undamaged; cleaning the connector fixed the fault and restored normal resistance.
Original source ↗
BYD DTC AI Analysis

B175A false positive after seat removal and refitting on BYD Qin Pro

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Vehicle: 2020 BYD Qin Pro. Symptom: DTC B175A appeared after replacing the right rear seat leather cover. Diagnosis: Inspected the wiring harness beneath the seat. The SRS harness was not clipped into its retaining slot; the seat frame pinched it instead. This compressed and deformed the insulation without breaking it, causing resistance to drop to 0Ω at specific seat positions. Repair: Rerouted the harness, reinforced the insulation with specialized harness tape, and clipped the SRS harness into the factory retaining clip to ensure adequate clearance from the seat frame. Cleared the DTC and tested by repeatedly adjusting the seat position; the fault did not recur.
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.