AU
B160A-00

This DTC indicates the Airbag Control Unit (ACU) detects the Driver Airbag (DAB) firing circuit resistance is below the calibrated threshold (close to 0 Ω), indicating a short circuit — Seal U

Safety System

This DTC indicates the Airbag Control Unit (ACU) detects the Driver Airbag (DAB) firing circuit resistance is below the calibrated threshold (close to 0 Ω), indicating a short circuit.

In the BYD SRS system, normal airbag circuit resistance ranges from 1.5 to 3.0 Ω.

A resistance of 0 Ω typically indicates a short between the positive and negative terminals in the airbag wiring harness, clock spring, or connector.

An internal driver circuit breakdown within the ACU can also cause this issue.

This fault triggers the safety system fail-safe mode, illuminates the instrument panel SRS warning light, and may prevent airbag deployment during a collision.

This severely compromises passive safety and requires immediate repair.

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Clock spring (airbag spiral cable) internal short circuit: Long-term steering wheel rotation wears and breaks the internal flexible ribbon cable insulation, causing direct wire contact and a short circuit.
  • 2Airbag wiring harness damaged and shorted to ground: A loose wiring harness retaining clip inside the instrument panel allows the harness to rub against the metal bracket, damaging the insulation and shorting the wire to the vehicle body ground.
  • 3Airbag connector water ingress and corrosion: Water enters the driver-side airbag connector (located under the steering wheel or on the airbag module) when driving through water or cleaning the interior, causing an electrolytic short circuit between the terminals.
  • 4ACU internal detection circuit breakdown: A damaged internal boost circuit or sampling resistor in the control unit causes the system to incorrectly read the airbag circuit resistance as 0.
  • 5Aftermarket modifications: Incorrect wiring when modifying the steering wheel or airbag, or installing an additional controller, causing a direct short in the airbag circuit.
What To Do
  • 1
    Safe power down: Disconnect the battery negative terminal and wait at least 3 minutes to dissipate residual system charge and fully discharge the SRS capacitor.
  • 2
    Fault confirmation: Connect the BYD dedicated diagnostic tool or a generic diagnostic tool. Read and confirm B160A-00 is a current fault (Active). Record the freeze frame data.
  • 3
    Visual inspection: Check if the yellow airbag connector under the steering wheel is loose, burnt, or has water ingress. Check the clock spring for visible damage or cracks.
  • 4
    Airbag unit isolation test: Remove the driver airbag module and connect a dedicated 2-3Ω airbag simulator resistor in place of the airbag. Power on the vehicle and check if the fault code changes to a history fault. If the fault code clears and does not return as a current fault, this indicates an internal short circuit in the airbag unit. Replace the airbag assembly.
  • 5
    Harness continuity check: Disconnect the ACU connector and the clock spring connector. Use a multimeter to measure the resistance between the two wires in the airbag circuit. The normal reading is infinite; if the resistance is 0, the harness has a short circuit. Measure the harness in sections (disconnect the intermediate connector) to determine whether the short circuit is in the steering wheel harness section or the instrument panel main harness section.
  • 6
    Clock spring inspection: Disconnect the connectors at both ends of the clock spring and directly measure its internal resistance. The resistance must be close to 0 Ω (continuity) and remain stable when turning the steering wheel. Replace the clock spring if the resistance fluctuates abnormally or a short circuit occurs while turning.
  • 7
    ACU internal fault determination: If the external wiring harness, clock spring, and airbag module are normal, measure the resistance from the ACU airbag drive pins to ground and to power. If a short circuit exists, the ACU has an internal breakdown. Replace the ACU and perform online programming and matching.
  • 8
    System verification: After repairing the short circuit, connect the airbag simulator, reconnect the battery, clear the fault code, and perform the SRS system self-check cycle. Confirm B160A-00 does not return and the airbag warning lamp turns off normally.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Internal short circuit in the clock spring of a BYD Qin Pro caused B160A-00.

✓
The vehicle has no collision history. The airbag warning light suddenly came on. Read DTC B160A-00 (driver airbag resistance: 0Ω). Removed the airbag and measured its resistance — normal at 2.1Ω. Disconnected the clock spring and measured the harness, finding a short circuit. Replaced the clock spring, clearing the fault. Root cause: prolonged use with the steering wheel at full lock wore through the internal wiring insulation, causing the positive and negative conductors to make direct contact.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

Airbag connector short circuit on BYD Song Pro after wading through water

✓
After driving through water, the airbag warning light stayed on. The scanner showed B160A-00. Found moisture inside the airbag connector under the steering wheel; electrolytic corrosion had caused a short circuit between the terminals. Cleaned and dried the connector, applied conductive protectant, and cleared the fault. Recommend checking the vehicle for water leaks to prevent further water ingress.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Tang DM: Wiring harness chafing caused intermittent short circuit

✓
Airbag light would illuminate intermittently; DTC B160A-00 would come and go. Found the dashboard wiring harness retaining clip had detached, letting the harness rub against the steering column bracket and wear through the insulation. On rough roads, the harness occasionally shorted to the body, giving zero resistance. Rewrapped and secured the harness. Fault resolved.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD e5 ACU internal fault falsely reporting zero resistance

✓
Taxi operator reported the airbag warning light on. Read DTC B160A-00. Inspected the airbag, clock spring and wiring harness – all normal. Measured the ACU output and found internal driver circuit damage, continuously outputting a low-resistance signal. Replaced the airbag control unit (ACU), performed online programming and matching, and resolved the fault.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Song MAX poor ground with abnormal resistance

✓
Airbag warning light on with DTC B160A-00. Inspection found a loose ACU ground wire bolt, causing abnormal voltage in the detection circuit and leading the system to falsely detect zero resistance. Also found the airbag connector loose. Serviced the ground point and tightened the airbag connector, then cleared the fault code. System returned to normal.
Original source ↗
Other Seal U 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]