AU
B17351B

DTC B17351B indicates the SRS (Supplemental Restraint System) control unit detects a communication interruption or open electrical connection between the right second-row side airbag module (typically located on the right rear seat side or C-pillar) and the main control unit — Atto 8

Safety System

DTC B17351B indicates the SRS (Supplemental Restraint System) control unit detects a communication interruption or open electrical connection between the right second-row side airbag module (typically located on the right rear seat side or C-pillar) and the main control unit.

Specifically, this open circuit fault indicates the airbag ignition circuit resistance falls outside the normal range (typically >10Ω or reading infinite).

This fault prevents the affected side airbag from deploying normally during a collision.

It may also deactivate the entire airbag system (entering fail-safe mode) and retain only the driver airbag function, severely compromising occupant side-impact protection.

The B17351B fault code on the Atto 8 indicates a medium-severity open circuit or communication break between the SRS control unit and the right second-row side airbag. This may stop that airbag, or parts of the airbag system, from working correctly in a crash. Common causes include a loose seat or C-pillar wiring connector, or a failed airbag module igniter. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Atto 8
  • 1Airbag wiring harness connector under the seat or inside the C-pillar trim panel is loose, disconnected, or making poor contact, especially near the adjustable seat slide rail where frequent adjustment causes the connector to loosen.
  • 2Open circuit in the right middle-row side airbag assembly internal igniter or module failure. Airbag module aging or an internal open circuit usually causes this.
  • 3Physical damage to the wiring harness, especially in the harness between the seat frame and body, where long-term bending and compression fracture the copper core (common in vehicles with frequent fore-and-aft seat adjustment).
  • 4Corroded, oxidized, or backed-out connector terminals causing increased terminal contact resistance due to vehicle wading, high-humidity environments, or liquid ingress during cleaning.
  • 5SRS control unit internal detection circuit fault. Though rare, damage to the control unit detection port for the right-side airbag circuit also triggers this fault.
What To Do
  • 1
    Use the BYD dedicated diagnostic tool (VDS or ED-400) to read the fault code, confirm whether B17351B is a current fault (Active) or a history fault (History), and record freeze frame data.
  • 2
    Switch off the ignition, disconnect the negative battery terminal and wait at least 90 seconds (to fully discharge the SRS capacitor). Remove the right middle-row seat or C-pillar trim panel and locate the side airbag module connector (usually yellow or orange, with a shorting bar).
  • 3
    Visually check that the connector is fully seated and the shorting bar operates correctly. Inspect the terminals for corrosion, oxidation, or backed-out pins. Clean the terminals with electrical contact cleaner if necessary.
  • 4
    Disconnect the airbag module connector. Using a multimeter, measure continuity between the harness-side connector and the SRS control unit (<1Ω). Measure insulation resistance to ground and power (>10MΩ) to confirm the wiring harness has no open or short circuits.
  • 5
    Connect the airbag simulator (typically a dedicated 2-3Ω resistor) to the wiring harness connector. Reconnect the battery and turn the ignition switch ON. Use the diagnostic tool to clear the fault code and read the data stream. Verify the system displays a normal resistance value (2-5Ω) and the fault code does not reappear.
  • 6
    If the simulator test passes, replace the right middle-row side airbag module assembly. If the fault persists, inspect and repair the wiring harness between the SRS control unit and the airbag, or replace the SRS control unit.
  • 7
    After completing the repair, reinstall all components and perform an SRS system self-check (normally, after turning the ignition switch ON, the airbag warning lamp illuminates for 6 seconds and then turns off). Perform a road test to confirm complete fault resolution.
Real-World Cases
BYD DTC AI Analysis

Right rear side airbag connector detached on E2 rideshare vehicle

✓
2019 BYD E2 ride-hailing vehicle with 85,000 km. Airbag warning light on. Read DTC B17351B. Inspection found frequent removal of the right rear seat for cargo had completely detached the side airbag connector. Reconnected the connector and secured the wiring harness with cable ties. Cleared the fault code; system returned to normal.
BYD DTC AI Analysis

Flood-damaged Qin EV: corroded airbag terminals

✓
A 2019 Qin EV had water enter the cabin from a blocked sunroof drain tube, pooling in the right C-pillar. After repairs, DTC B17351B appeared. Disassembling the right second-row side airbag connector revealed severely oxidised, green terminals. Cleaned the terminals with electronic cleaner and applied conductive protectant. Resistance measurements returned to normal, clearing the fault.
BYD DTC AI Analysis

E3 seat wiring harness broke due to prolonged flexing

✓
The owner of a 2020 E3 with 120,000 km reported the airbag warning light illuminating intermittently. The diagnostic tool showed intermittent fault code B17351B. Inspection found the wiring harness beneath the right rear seat had fractured copper cores with intact insulation at the seat rail mounting point, caused by repeated seat adjustments over time (hidden fault). Stripping back the harness revealed the internal conductor was 80% broken. Resoldering the joint and reinforcing the protection resolved the fault.
BYD DTC AI Analysis

Did not clear fault after replacing airbag module.

✓
Replaced the right second-row side airbag module on an E2 during accident repair, but DTC B17351B persisted after installation. The new module connector seated properly, yet the scan tool showed infinite resistance. Found that pulling during removal of the old airbag had damaged the wiring harness, causing the terminals to back out inside the connector. Repairing the terminals cleared the fault. Avoid yanking the wiring harness when servicing airbag systems.
Other Atto 8 Fault Codes
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.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.B110B07This fault code indicates abnormal operation of the internal air pump (sampling pump) in the PM2.5 air quality detection module. The PM2.5 detector uses the laser scattering principle to measure particulate concentration and requires a built-in air pump to draw ambient air into the detection chamber at a constant flow rate. The ECU sets this code when it detects an open or short in the air pump drive circuit, abnormal current (stall or free-running), or abnormal speed feedback. This fault causes the automatic air conditioning system to lose air quality sensing capability, preventing automatic switching between fresh air and recirculation modes. The instrument cluster air quality display may show '--' or a fixed value, but the fault does not affect the vehicle powertrain or basic air conditioning cooling and heating functions.B173CDTC B173C indicates the Supplemental Restraint System (SRS) detects the Right Second Row Side Airbag squib circuit resistance exceeds the calibrated threshold (typically >4.5Ω). This fault is an active diagnostic result of the SRS system, indicating a high-resistance condition in the circuit between the Airbag Control Unit (ACU) and the airbag module. Causes for excessive resistance include increased contact resistance, a partially broken wiring harness, terminal oxidation, or an aging squib wire inside the airbag module. This fault causes the system to mark the airbag circuit as 'unreliable', meaning the airbag may fail to deploy during a collision. The fault typically illuminates the instrument cluster airbag warning light (SRS light) continuously, and some models also sound a warning buzzer.
Common problems reported for Atto 8 →Atto 8 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.