AU
B160B-00

DTC B160B-00 indicates the SRS (Supplemental Restraint System) ECU detects the driver's front airbag (steering wheel airbag) igniter circuit resistance is below the calibrated threshold (usually <1 — Atto 8

Safety System

DTC B160B-00 indicates the SRS (Supplemental Restraint System) ECU detects the driver's front airbag (steering wheel airbag) igniter circuit resistance is below the calibrated threshold (usually <1.0Ω).

Normal airbag igniter resistance is 2.0-3.0Ω.

Low resistance usually indicates a circuit short to ground, an internal short in the airbag module, or abnormal connector continuity.

This fault causes the SRS ECU to register an abnormal airbag circuit.

The airbag may fail to deploy during a collision or deploy unintentionally while driving.

Consequently, the system illuminates the airbag warning lamp and disables the airbag function.

5
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Clock spring (spiral cable) internal short circuit: Frequent steering wheel rotation wears the internal flat cable insulation, causing a short circuit between the core wires or between a core wire and the housing. This is the most common cause.
  • 2Airbag connector short circuit: Water ingress, bent pins, terminal corrosion, or foreign objects entering the yellow dedicated connector (usually located under the steering wheel or on the side of the steering column) cause abnormal continuity.
  • 3Airbag module internal fault: Igniter bridge wire short circuit or moisture in the pyrotechnic charge causing abnormally low resistance.
  • 4Wiring harness chafed and shorted: Wiring harness near the steering column rubs against the metal bracket or steering wheel frame, causing insulation damage or shorting to body ground.
  • 5SRS ECU internal sampling circuit fault: Damaged ECU internal A/D converter or reference resistor causes distorted resistance sampling (less common).
What To Do
  • 1
    Safety Preparation: Turn off the ignition, disconnect the 12V battery negative terminal, and wait at least 90 seconds to fully discharge the SRS capacitor. Wear an anti-static wrist strap.
  • 2
    Visual inspection: Check the yellow airbag connector under the steering wheel for looseness, water ingress, or obvious corrosion; check the clock spring for visible damage or burn marks; check the steering column wiring harness for wear.
  • 3
    Disconnect the airbag: Carefully remove the driver airbag module (use a special tool or screwdriver to release the spring clips on both sides) and disconnect the airbag connector (short-circuit first to prevent static electricity).
  • 4
    Measure the clock spring: Use a digital multimeter (high-impedance setting; do not use the buzzer setting) to measure the resistance across both ends of the clock spring. Normal resistance is 0–1 Ω (continuity with extremely low resistance). If the measured resistance is <0.5 Ω and both ends have continuity to ground, replace the clock spring.
  • 5
    Measure the wiring harness: Disconnect the SRS ECU connector and measure the resistance to ground of the circuit from the ECU to the airbag. The resistance must be infinite. If continuity exists, locate the damaged point in the wiring harness.
  • 6
    Replacement verification: Connect a 2-3Ω dummy load (special airbag test resistor) to the clock spring. Clear the fault code. If the code does not return, the airbag module is faulty. If the code persists, the wiring harness or ECU is faulty.
  • 7
    Repair and verification: Repair the short circuit or replace the faulty component (clock spring, airbag module, or wiring harness). Reconnect the battery. Use VDS2000 or a BYD dedicated diagnostic tool to clear the fault code. Perform an SRS system self-check. Confirm the fault code does not reappear and the airbag warning light turns off.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Qin EV300 clock spring internally shorted, causing lower than normal resistance

✓
The airbag light was on steady when the vehicle arrived. Pulled DTC B160B-00. Inspected and found the steering wheel felt notchy when turned. Disconnected the airbag connector and measured only 0.2 ohms across the clock spring, with both terminals showing continuity to ground. Disassembled the clock spring and found the ribbon cable insulation damaged, causing a short. Replaced with a genuine clock spring (part number: KJ-3479010). Resistance returned to 2.3 ohms and the fault cleared.
BYD DTC AI AnalysisFrom Chinese market (translated)

Qin 80: Airbag connector shorted due to water ingress after wading

✓
The vehicle drove through water approximately 40cm deep. Afterwards, the airbag warning light illuminated. The scan tool showed DTC B160B-00. Inspection found visible water traces and copper corrosion inside the yellow connector beneath the steering column; insulation resistance between pins had dropped to 0.8Ω. Cleaned the connector with electrical contact cleaner, dried it thoroughly, then applied special conductive grease. After repair, insulation resistance recovered to 2.1Ω. Cleared the fault code; it has not returned. Recommend checking the vehicle's sealing, especially whether the drain holes are blocked.
BYD DTC AI AnalysisFrom Chinese market (translated)

Modified steering wheel caused abnormal circuit impedance

✓
Owner fitted an aftermarket racing steering wheel and third-party airbag harness adapter. DTC B160B-00 appeared intermittently. Inspection found the modified harness used a resistor with too-low resistance (0.5Ω) to simulate the airbag load, causing the SRS ECU to detect insufficient resistance. Removed the modified components and refitted the original steering wheel and airbag assembly; the fault cleared. Advised the owner that any future modifications must use an equivalent resistor meeting BYD SRS system specifications (2.0±0.3Ω).
BYD DTC AI AnalysisFrom Chinese market (translated)

Worn steering column wiring harness caused short to ground

✓
At 80,000 km, the airbag warning light illuminated intermittently, particularly on rough roads. Measuring during the fault showed the airbag circuit resistance to ground was 0.3Ω. Inspection found a sharp edge on the mounting bracket below the steering column. The edge had chafed through the airbag wiring harness insulation due to prolonged vibration, causing the copper conductors to short against the bracket. Repaired the damaged harness by re-wrapping with insulation tape and fitting protective sleeving, then rerouted the wiring to avoid contact with the metal edge. Completely resolved the fault.
BYD DTC AI AnalysisFrom Chinese market (translated)

Airbag module internal igniter short circuit

✓
No collision history, but the airbag warning light suddenly illuminated with DTC B160B-00 that could not be cleared. Disconnected the airbag module connector and measured resistance between the module terminals: 0.6 Ω (normal: 2–3 Ω). Determined an internal igniter bridge wire short in the airbag. Replaced the driver airbag assembly, also replacing the mounting bolts and tightening them to 7.5 N·m. Performed coding and configuration with the special tool, and the system returned to normal.
Other Atto 8 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.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
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. Sources: [1]