AU
B160A1A

DTC B160A1A indicates abnormally high resistance (open circuit or high-resistance condition) in the driver-side front airbag (stage 1) ignition circuit — Atto 3

Safety System

DTC B160A1A indicates abnormally high resistance (open circuit or high-resistance condition) in the driver-side front airbag (stage 1) ignition circuit.

This is a critical Supplemental Restraint System (SRS) safety fault.

Normal airbag igniter resistance is 1.5-3.5Ω.

If the system detects resistance continuously exceeding the threshold (typically >5Ω or open circuit), it identifies an ignition circuit integrity fault.

The SRS control unit then illuminates the instrument cluster airbag warning light and enters fail-safe mode.

This condition may prevent the driver-side airbag from deploying during a collision.

The fault indicates an electrical connection issue in the circuit, not an explosion risk from the airbag itself.

5
Cases Logged
5
Causes
Likely Causes — Atto 3
  • 1The flat cable inside the clock spring is broken, fatigue-damaged, or has poor contact. Internal open circuits easily occur, especially after frequently turning the steering wheel to full lock or prolonged left-to-right rotation.
  • 2The yellow airbag wiring harness connector below the steering wheel (usually with a double-locking mechanism) is not fully seated, pins are backed out, oxidized or corroded, or contact resistance is excessive.
  • 3Abnormally high resistance or open circuit in driver airbag module internal igniter, or damaged module (rare).
  • 4Airbag wiring harness cut, damaged, poorly connected, or with damaged insulation or failed waterproof sealing caused during accident repair or steering wheel modification.
  • 5In very rare cases, the cause is an internal sampling circuit fault in the SRS control unit, a software version defect, or a poor ground.
What To Do
  • 1
    Safety Preparation: Disconnect the negative battery cable and wait at least 3 minutes to discharge residual capacitor charge to prevent accidental airbag deployment during repair.
  • 2
    Fault Confirmation: Read SRS system fault codes using the BYD dedicated diagnostic tool. Confirm B160A1A is a current fault (Active) and does not clear. Record the freeze frame data.
  • 3
    Initial inspection: Verify the yellow airbag connector below the steering wheel (where the spiral cable connects to the body wiring harness) is fully seated. Inspect the locking tab for breakage and the wiring harness for obvious damage or crush marks.
  • 4
    Clock spring inspection: Remove the steering wheel and disconnect the airbag module connector. Measure the resistance between the terminals on both sides of the clock spring using a multimeter. Standard resistance: <1Ω. Slowly turn the steering wheel through its full range and verify the resistance remains stable without fluctuation.
  • 5
    Circuit continuity check: If the clock spring is normal, measure the continuity and insulation of the wiring harness from the clock spring to the SRS control unit. Carefully inspect the wiring harness passing through the steering column area for wear.
  • 6
    Airbag module inspection: If the wiring is normal, use a dedicated jumper wire or multimeter to directly measure the resistance between the two airbag module igniter terminals. The normal range is 1.5-3.5Ω. If the resistance is too high, replace the module.
  • 7
    Repair/Replace: Based on measurement results, replace with an OEM clock spring (70% probability), repair poor wiring harness contact (20% probability), or replace the airbag module (10% probability). Never use aftermarket resistors to bypass the module.
  • 8
    System reset verification: Reconnect all connectors and the battery. Clear the fault code and perform the SRS system self-check cycle (cycle the ignition ON-OFF three times or perform a driving self-check). Verify the warning light turns off and the fault code does not return.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Qin Pro DM clock spring internal open circuit

✓
Symptoms: The airbag warning light stayed on suddenly during normal driving. Previously, the steering wheel made abnormal noise at full lock. Diagnosis: A diagnostic tool read DTC B160A1A. Removed and inspected the clock spring, revealing wear at the base. Static resistance measured 3.5Ω by multimeter (abnormal). Resistance intermittently went to infinite (open circuit) when turning the steering wheel. Confirmed the internal ribbon cable was broken. Resolution: Replaced the OEM clock spring assembly, cleared the fault codes, and the system returned to normal. Cost: about 300–600 yuan.
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Song Pro: Airbag connector loose, poor contact

✓
Symptoms: Airbag warning light stays on after accident repair. DTCs reappear after clearing. Diagnosis: Yellow airbag connector under steering wheel not fully seated. Terminal retraction caused contact resistance 5.8 Ω (excessive). Resolution: Repaired terminal using extraction tool. Reconnected and confirmed locking click. Secured wiring loom with cable ties to prevent loosening. Cleared DTCs; fault resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD e5 commercial vehicle: clock spring ribbon cable fatigue wear

✓
Symptoms: 180,000 km rideshare vehicle. Airbag warning light flashes intermittently then stays on, worse in damp weather. Diagnosis: Prolonged full-lock steering caused the clock spring to exceed its fatigue life. Resistance unstable (fluctuating 1.2–6.8 Ω), jumping when the housing was tapped. Fix: Replaced with a compatible clock spring, greased rotating parts, advised avoiding prolonged full-lock steering. Fault resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Tang DM airbag module internal fault

✓
Symptoms: Airbag warning light on with no accident history. Fault returned one month after clock spring replacement. Diagnosis: Confirmed the replacement clock spring was normal (0.8Ω). Disconnected the connector and installed a 2.5Ω dummy resistor at the circuit end; the fault could be cleared, indicating a module issue. Removed and tested the airbag igniter — measured 8.2Ω resistance, severely out of specification. Resolution: Replaced the driver-side airbag module and checked the SRS control unit version at the same time. Fault fully resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

Steering wheel modification on a BYD Yuan EV damaged the wiring harness.

✓
Symptoms: After reverting from an aftermarket racing steering wheel to the factory unit, the airbag warning light stayed on with DTC B160A1A. A previous attempt to bypass with a resistor had no effect. Diagnosis: Found the wiring harness between the clock spring and airbag module cut and joined with electrical tape. Temperature changes and vibration loosened the tape, causing copper oxidation and a contact resistance of 4.2Ω. Insulation damage was also present. Resolution: Removed the splice point and repaired using a sealed waterproof connector or a soldered splice with heat-shrink tubing, achieving a stable resistance of 2.0Ω. Recommend avoiding modifications that damage the factory wiring harness.
Other Atto 3 Fault Codes
P0A0DBattery Energy Control Module Requested MIL IlluminationP0AA6Hybrid Battery Voltage System Isolation FaultP1A00Drive Motor "A" Performance — BYD proprietaryB1108For 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.
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]