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B162A

DTC B162A indicates the airbag control module (SRS ECU) detects a driver airbag ignition circuit resistance of 0 Ω or below the 1 — Qin Plus

Safety System

DTC B162A indicates the airbag control module (SRS ECU) detects a driver airbag ignition circuit resistance of 0 Ω or below the 1.5 Ω threshold, identifying a short to ground or a shorted circuit.

In the BYD SRS system, this circuit includes the clock spring, spiral cable, connectors, and airbag inflator.

A 0 Ω resistance means current may flow directly to ground.

The ECU disables the airbag to prevent accidental deployment and illuminates the instrument cluster airbag warning lamp.

This fault constitutes a hard short circuit, unlike an open circuit (infinite resistance).

However, broken wires inside the clock spring contacting each other or grounding can also cause an intermittent short circuit.

This fault prevents the driver front airbag from deploying during a collision, severely compromising passive safety.

5
Cases Logged
5
Causes
Likely Causes — Qin Plus
  • 1Damaged insulation on the internal flat cable of the steering wheel clock spring (spiral cable) causes a wire short to ground or inter-turn short circuit. This commonly occurs in older vehicles or from frequent full-lock steering.
  • 2Driver's airbag connector (yellow plug) pins bent, backed out, or corroded by water ingress, causing a short between the positive and negative pins or a short to ground.
  • 3The airbag wiring harness chafes near the steering column. Damaged insulation allows the wire to contact the metal frame, causing a short to ground.
  • 4Airbag inflator internal squib short circuit (abnormally low resistance); typically indicates an airbag unit fault or incorrect replacement after an accident.
  • 5Internal fault in the SRS control module monitoring circuit, false short-circuit detection, or incorrect clock spring installation causing an internal short circuit during rotation.
What To Do
  • 1
    Safety Preparation: Disconnect the battery negative terminal and wait at least 3 minutes to discharge residual charge in the system capacitors. Wear an anti-static wrist strap. Do not use the resistance setting of a standard multimeter to measure directly in the airbag area (use a high-impedance digital multimeter or a dedicated diagnostic tool).
  • 2
    Visual inspection: Verify the yellow airbag connector below the steering wheel is fully locked. Inspect the inside of the connector for water stains, oxidation, or deformed pins. Inspect the clock spring exterior for damage or burn marks.
  • 3
    Sectional measurement: Remove the driver airbag. Measure the resistance to ground at the lower end of the clock spring (towards the SRS ECU). Resistance must be infinite. If the resistance is 0, inspect the floor wiring harness for chafing or short circuits. Measure the resistance at the upper end of the clock spring (airbag side). Normal resistance is 2-3 Ω. If the resistance is close to 0 Ω, replace the clock spring.
  • 4
    Component isolation: Disconnect the clock spring from the SRS ECU and measure the clock spring resistance separately. If normal, measure the airbag module resistance (should be 2-3 Ω). If the airbag resistance is 0, replace the airbag assembly.
  • 5
    Repair/Replacement: Replace the faulty clock spring or repair the damaged wiring harness. Use genuine parts. Set the new clock spring to the center position before installation to prevent snapping the internal cable when turning the steering wheel to full lock.
  • 6
    System verification: Connect the battery. Use a BYD dedicated diagnostic tool (such as VDS2000/VDS6000) to clear the fault code. Perform 'SRS system self-check' and 'Configuration settings' (e.g., after replacing the airbag or clock spring). Confirm the fault code does not return and the warning lamp turns off.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Qin Pro DM clock spring internal short circuit

✓
Symptoms: Dashboard airbag warning light constantly on; no accident history. Diagnosis: Read DTC B162A (driver airbag circuit resistance too low). Clock spring resistance fluctuated between 0.5–1.2 Ω (normal: 2–3 Ω). Disassembly found worn insulation on the internal flat cable, causing a local short circuit. Solution: Replaced the clock spring with genuine part KZ-541XXX, re-centred it during installation, then cleared fault codes. The system returned to normal.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Song Pro airbag connector short circuit due to water ingress

✓
Symptoms: Airbag warning light comes on after rain or car wash, and occasionally on rough roads. Diagnosis: B162A intermittent fault. Inspected the yellow connector under the steering wheel; the seal was missing and green copper corrosion was inside. Resistance measured between pins indicated occasional short circuits. Solution: Disconnected the battery, cleaned the connector with electronic contact cleaner, blew it dry, applied conductive grease, and replaced the locking clip with a new one to ensure a proper seal. Fault resolved.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Han EV combination switch assembly fault

✓
Symptoms: Airbag warning light flashes when turning the steering wheel; multifunction buttons not working. Diagnosis: Live data showed the driver airbag circuit resistance jumping between 0Ω and 5Ω as the steering wheel turned. This indicated an internal cable break in the clock spring (integrated in the combination switch) that caused a short to ground. Solution: Replaced the combination switch assembly (includes clock spring, HA-341XXX). Calibrated the steering angle sensor and wrote the airbag configuration using a diagnostic tool.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD Tang DM-i short circuit after accident repair

✓
Symptom: After a front collision and airbag replacement, the fault light stayed on. Diagnosis: Pulled DTC B162A. New airbag resistance measured normal, but the harness side showed 0 Ω to ground. Found the clockspring had been pinched during the impact, causing an internal short. An SRS ECU connector pin had also retracted and was contacting the housing. Solution: Replaced the clockspring, repaired the connector pin, performed the airbag reconfiguration procedure, and cleared the codes. System returned to normal.
Original source ↗
BYD DTC AI AnalysisFrom Chinese market (translated)

BYD e5 taxi wiring harness chafed and shorted

✓
Symptoms: High-mileage taxi (250,000 km) with airbag warning light on and horn not working. Diagnosis: DTCs B162A and B162B both present. Inspection found the wiring harness under the clock spring worn through from prolonged full-lock steering. Damaged insulation caused wires to contact steering column metal and short to ground. Repair: Replaced clock spring, fitted heat-resistant protective sleeving to harness at steering column wear point, and rerouted harness to prevent excessive flexing.
Original source ↗
Other Qin Plus 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]