AU
B170D-00

This DTC indicates the SRS (Supplemental Restraint System) control module detects a disconnected right side curtain airbag or interrupted communication — Atto 8

Safety System

This DTC indicates the SRS (Supplemental Restraint System) control module detects a disconnected right side curtain airbag or interrupted communication.

When the ignition switch is ON, the SRS module monitors the airbag inflator circuit resistance (normal range: 2.0-4.0 Ω) to verify the airbag module's presence.

If the SRS module detects an open circuit (infinite resistance), a resistance value exceeding the threshold (>10 Ω), or a loss of communication, it flags the airbag as "not connected".

Potential causes include an open airbag wiring harness, a loose connector, oxidized or corroded terminals, an internal open circuit in the airbag module, or a failed internal diagnostic circuit in the SRS control module.

This fault eliminates right-side head protection during a side impact or rollover.

As a critical passive safety system fault, it requires immediate repair.

The B170D-00 fault code on the Atto 8 indicates the SRS control module detects the right side curtain airbag is disconnected or not communicating. Severity is medium, but it affects crash protection and should be repaired promptly. Common causes include a loose or unseated curtain airbag connector near the C-pillar/headliner, or damaged wiring in the A-pillar, C-pillar, or headliner. Visit an authorised dealer for diagnosis and repair. Typical repair cost data is available from recorded cases.
5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Right C-pillar and headliner curtain airbag wiring harness connector loose, not fully seated, or locking mechanism failed (common due to improper reassembly after headliner repair or windshield replacement).
  • 2Airbag wiring harness chafed or broken inside the A-pillar, C-pillar, or headliner trim (repeated door operation or vibration causes harness bending fatigue and insulation damage).
  • 3Open circuit in right curtain airbag module internal igniter (airbag aging, moisture, or previous impact disconnected the internal circuit)
  • 4Oxidation, corrosion, or poor contact at the connector terminals between the SRS control module and the airbag (especially common in water-damaged vehicles or high-humidity environments).
  • 5Failure to install genuine parts after a previous accident triggered airbag deployment, or use of aftermarket parts or simulators with mismatched resistance.
What To Do
  • 1
    Safety preparation: Turn the vehicle OFF. Disconnect the low-voltage battery negative terminal and wait at least 90 seconds to fully discharge the SRS energy storage capacitor. Wear an anti-static wrist strap to prevent airbag deployment.
  • 2
    Visual inspection: Remove the right A-pillar upper trim, C-pillar trim, and right edge of the headliner. Verify the yellow dedicated curtain airbag connector (usually located at the junction of the C-pillar and headliner) is fully seated, the locking tab is fully engaged, and the wiring harness shows no obvious damage.
  • 3
    Resistance measurement: Disconnect the SRS control module connector, locate the right curtain airbag circuit pins, and measure the circuit resistance. Normal resistance is 2.0-4.0 Ω. Infinite resistance indicates an open circuit in the wiring harness or airbag. A 0 Ω reading indicates a possible short circuit.
  • 4
    Sectional wiring harness continuity check: If resistance is abnormal, measure wiring harness continuity in sections. Check specifically for internal breaks at the C-pillar to headliner transition area and wiring harness retaining clips (outer insulation intact but internal copper strands broken).
  • 5
    Airbag module test: After verifying the wiring harness is normal, perform a bridge test using a dedicated airbag substitute resistor (2Ω). If the fault code clears, the airbag module has an internal fault.
  • 6
    Repair and Verification: Repair the wiring harness (soldering + heat-shrink tubing) or replace the airbag module. Reconnect all connectors (listen for the locking 'click'). Reconnect the battery. Use the VDS diagnostic tool to clear the fault code and perform the 'SRS system self-check'. Confirm B170D-00 does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI Analysis

BYD Qin EV right side curtain airbag connector loose

✓
After starting the vehicle, the airbag warning light on the instrument panel stayed on. Read fault code B170D-00. Removed the right C-pillar trim and headliner edge to inspect. Found the curtain airbag harness yellow connector not fully seated in the socket and the locking clip not engaged. Suspected improper installation during a previous headliner replacement at a repair shop. Re-seated the connector firmly and confirmed the locking mechanism fully engaged. Cleared the fault code; the SRS system self-test passed. Fault resolved.
Original source ↗
BYD DTC AI Analysis

BYD Song PLUS intermittent open circuit in curtain airbag wiring harness

✓
When driving on rough roads, the airbag warning light illuminated intermittently. DTC B170D-00 appeared intermittently, with no faults when stationary. Inspection revealed an improperly secured wiring harness inside the right C-pillar. During door operation or body flex, the harness experienced repeated tension, causing fatigue fractures in the internal copper wires while the outer insulation remained intact. Stripping back the harness revealed multiple broken copper wires. Repaired the harness by soldering and sealing with heat shrink tubing, then re-routed and secured it with cable ties to a rigid body bracket to prevent interference with the door mechanism. A one-week follow-up confirmed the fault did not recur.
Original source ↗
BYD DTC AI Analysis

BYD Tang DM: Internal open circuit in right side curtain airbag module

✓
After powering on the vehicle, the instrument cluster continuously displayed 'Please Check Airbag System'. Read DTC B170D-00 but could not clear it. Disconnected the SRS module and measured infinite resistance in the right curtain airbag circuit, confirming an open circuit fault. Removed the right headlining trim, disconnected the airbag connector, and measured resistance directly across the airbag module terminals – again infinite (normal value 2-3Ω). Diagnosed an internal igniter open circuit in the curtain airbag module. Replaced the right curtain airbag module with a genuine unit. Used VDS to perform ECU configuration and coding. After clearing the fault codes, the system returned to normal.
Original source ↗
BYD DTC AI Analysis

BYD e5 right-side airbag connector water ingress and oxidation

✓
Ride-hailing commercial vehicle, airbag warning light stays on, DTC B170D-00. The vehicle had previously waded through water up to sill height. Removed and inspected the right C-pillar airbag connector, found green copper rust and white oxide crystals on the terminal surfaces, causing excessive contact resistance (measured 15Ω). Cleaned the terminals with electronic contact cleaner, applied special conductive grease to enhance contact, and fitted waterproof tape and a dust boot around the connector. Cleared the DTC; the airbag light went out. A three-month follow-up confirmed the fault had not returned.
Original source ↗
BYD DTC AI Analysis

BYD Han EV: Airbag connector unsecured on new vehicle

✓
One week after taking delivery of the new vehicle, the instrument cluster intermittently displayed ‘Airbag System Fault’. DTC B170D-00 was logged as an intermittent history code. Inspection revealed that although the right-hand curtain airbag connector had been correctly inserted at the factory, the locking tab was not fully pressed down. On rough roads, slight movement could occur, causing signal interruption. Removed and reconnected the connector, ensuring the locking tab fully engaged (audible secondary lock click), applied a small amount of conductive grease to the terminals to prevent fretting corrosion, cleared the DTC, and monitored for one week with no recurrence.
Original source ↗
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.