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 — Atto 3

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.

3
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1Short circuit to ground due to worn and damaged SRS wiring harness insulation under the right rear seat: During seat sliding or height adjustment, the yellow SRS wiring harness under the seat rubs against the metal slide rails or springs. Damaged insulation exposes the copper wire, causing direct contact with the body ground.
  • 2Airbag connector water ingress or bent pin short circuit: The right rear side airbag connector is located on the side of the seat backrest or inside the C-pillar trim panel. Water easily enters the connector during vehicle wading, improper car washing, or the rainy season, causing a short circuit between 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: Internal short circuit in the airbag igniter bridge wire, or damp propellant causing abnormally low resistance. This condition is rare but requires replacing the entire airbag module.
  • 4SRS control module internal detection circuit fault: A damaged resistance detection circuit inside the control module falsely reports a 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 clip the SRS wiring harness properly 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 dedicated diagnostic tool VDS or Launch X431 to confirm DTC B175A. Check the resistance value in the freeze frame data (must display 0.0Ω). Check for accompanying SRS fault codes (e.g., 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 or 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 (vehicle body side) and body ground. The reading must show infinite resistance (OL). A reading of 0Ω or close to 0Ω 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 a high-impedance multimeter) to measure the resistance of the airbag assembly (gas generator). The normal range is 1.5-3.5 Ω. If the reading is 0 Ω or near 0 Ω, it indicates an internal short circuit in the airbag module. Replace the right rear side airbag module. (Note: Verify the airbag is powered off during measurement and use the dedicated resistance measurement mode to prevent accidental deployment.)
  • 6
    SRS control module verification: If the wiring harness and airbag module are normal, suspect an SRS control module fault. Inspect the control module connector (usually located under the center console or behind the center armrest) for looseness. Use an oscilloscope to check the diagnostic signal output waveform from the control module. If necessary, replace and recode the SRS control module.
  • 7
    System reset and verification: After completing the repair, reconnect all connectors (listen for a locking click), connect the battery, and clear the fault code. Turn the ignition switch to the ON position and observe the instrument cluster airbag warning light: it should turn off after 6 seconds. Read the data stream with a diagnostic tool to confirm the right rear side airbag resistance displays within the normal range (1.5-3.5Ω). Finally, perform a seat fore-and-aft sliding test to verify 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 Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.
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.