AU
B168600

DTC B168600 indicates the SRS (Supplemental Restraint System/airbag) control module detects an abnormal configuration status in "Circuit 2" (typically the front passenger-side airbag deployment circuit) — Atto 8

Safety System

DTC B168600 indicates the SRS (Supplemental Restraint System/airbag) control module detects an abnormal configuration status in "Circuit 2" (typically the front passenger-side airbag deployment circuit).

In the BYD Qin PRO airbag architecture, the control module determines system status by monitoring circuit resistance (standard value 2.0–3.0 Ω) and configuration data. "Invalid configuration" means the control module reads a circuit resistance outside the threshold (open circuit >10 Ω or short circuit <1 Ω), or detects circuit configuration data that does not match the vehicle VIN or lacks correct coding.

This fault may prevent the passenger-side airbag from deploying properly during a collision.

The system also illuminates the instrument cluster airbag warning light and may disable the entire airbag system to enter fail-safe mode.

The B168600 fault code on the Atto 8 indicates an invalid configuration in the front passenger airbag circuit, meaning resistance is outside normal range or coding doesn't match the vehicle. Severity is medium. Common causes include a damaged airbag igniter or loose/corroded yellow connector behind the glove box. Visit an authorised dealer for repair. Typical repair cost data is available from 4 recorded cases.
4
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Resistance drift or damage in the front passenger airbag module internal igniter, causing abnormal circuit resistance.
  • 2Yellow connector between the floor wiring harness and the airbag module (usually behind the glove box or on the right side of the center console) is loose, or has backed-out pins, oxidation, or corrosion from water ingress.
  • 3Internal open or short circuit in the spiral cable (clock spring) affecting the circuit 2 signal transmission path.
  • 4Outdated SRS control unit (ACU) software or a hardware fault causes incorrect monitoring of Circuit 2.
  • 5Airbag wiring harness connector terminal corrosion due to prior vehicle wading, interior water ingress, or high-humidity environments.
What To Do
  • 1
    Use the BYD dedicated diagnostic tool (VDS2000/VDS3000) to read all DTCs. Verify B168600 is a current fault, not a history fault, and record the circuit resistance value from the freeze frame data.
  • 2
    Disconnect the battery negative cable and wait at least 3 minutes to allow the SRS capacitor to fully discharge, preventing accidental airbag deployment.
  • 3
    Remove the glove box or center console right trim panel. Check the passenger-side airbag wiring harness connector (yellow marking) for looseness, water ingress, or oxidized pins. Clean and reconnect if necessary.
  • 4
    Disconnect the airbag module connector and use a multimeter to measure the resistance of circuit 2 on the wiring harness side. The normal resistance is 2.0-3.0 Ω. Measure the insulation resistance to ground and to the power supply. The resistance must be greater than 1 MΩ.
  • 5
    Check clock spring (spiral cable) continuity, specifically the 2-pin circuit connecting to the passenger-side airbag. Inspect for internal open or short circuits.
  • 6
    If wiring harness measurements are normal, check the SRS control module software version against the BYD Technical Service Bulletin (TSB) and update to the latest software version if necessary.
  • 7
    After replacing the faulty component (airbag module, wiring harness, or ACU), use the diagnostic tool to perform the 'SRS System Configuration' or 'Airbag Coding' function to ensure the new component matches the vehicle.
  • 8
    Clear the fault code and reconnect the battery. Turn the ignition switch ON and observe if the airbag warning light turns off after the self-check. Perform a system self-check cycle to verify.
Real-World Cases
BYD DTC AI Analysis

BYD Qin Pro DM passenger-side airbag connector pin backed out

✓
A 2019 BYD Qin Pro DM with 30,000 km displayed 'Check Airbag System' on the dash. The scan tool read active DTC B168600. Disassembling the passenger side airbag harness revealed the female terminal inside the yellow connector had backed out, driving contact resistance to 15 Ω. After reseating the terminal and applying conductive paste, circuit resistance returned to 2.3 Ω, clearing the fault.
BYD DTC AI Analysis

Qin PRO petrol SRS control module software fault

✓
2018 BYD Qin Pro petrol, no accident history, intermittent B168600 DTC. Inspection found SRS control module had an early software version with a known defect that falsely reports Circuit 2 faults. Updated ACU software to latest version (downloaded from BYD after-sales system), performed configuration write. Fault has not returned.
BYD DTC AI Analysis

Airbag wiring harness corrosion on water-wading vehicle

✓
A Qin Pro DM had previously waded through water up to carpet height. After repair work, DTC B168600 appeared. Inspection found the floor harness waterproof plug under the front passenger seat damaged, allowing moisture ingress that oxidised and blackened the airbag circuit 2 connector terminals. Replaced the floor wiring harness assembly and repaired the waterproofing to resolve the fault.
BYD DTC AI Analysis

Replaced passenger airbag without configuration, causing fault.

✓
After the front passenger airbag was replaced on a Qin Pro, the technician cleared the fault codes without using a diagnostic tool to configure the SRS system. DTC B168600 returned after two days of driving. The technician then performed the 'SRS module configuration' function using VDS2000 and entered the correct vehicle configuration code. The system recognised the new airbag module, completely resolving the fault.
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.