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AU
B163B1A

DTC B163B1A indicates the squib circuit resistance of the front passenger side airbag (typically mounted on the outboard side of the front passenger seat or inside the right front door trim panel) falls below the minimum threshold set by the SRS control module (ACM) (typically below 1 — Atto 3

Safety System

DTC B163B1A indicates the squib circuit resistance of the front passenger side airbag (typically mounted on the outboard side of the front passenger seat or inside the right front door trim panel) falls below the minimum threshold set by the SRS control module (ACM) (typically below 1.0-1.5 Ω; normal range is 2.0-3.0 Ω).

This condition indicates a partial or complete short in the squib circuit.

Damaged wiring, water ingress at the connector, or an internal airbag fault can cause this issue.

This fault triggers the safety protection mechanism.

The SRS system disables the airbag circuit to prevent unintended deployment and illuminates the airbag warning light on the instrument cluster.

During a side impact, this airbag may fail to deploy normally, severely compromising occupant safety.

3
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Right front door hinge wiring harness wore through and shorted, causing low resistance.

✓
Symptoms: The airbag warning light on the dashboard stays on continuously. Scan tool shows DTC B163B1A (current). The vehicle has no collision history, but the right front door recently had body repair. Diagnosis: Disconnected the battery, then removed the passenger side airbag connector. The airbag itself measured 2.3Ω (normal). On the harness side, only 0.2Ω remained between the two wires – a short circuit. Removed and inspected the rubber boot at the right front door hinge. The harness inside had been crushed and damaged during the repair, shorting the positive and negative conductors. Resolution: Repaired the damaged harness (re-insulated and wrapped with tape). Rerouted the harness to prevent rubbing. Cleared the fault code, and the system returned to normal.
Original source ↗
BYD DTC AI Analysis

Passenger seat airbag connector shorted due to water ingress.

✓
Symptoms: After the vehicle waded through water (up to seat level), the airbag warning light flashed and then stayed on. DTC B163B1A appeared intermittently, with higher frequency in humid weather. Diagnosis: Inspected the airbag connector under the passenger seat. Found the connector seal aged and missing, with visible water stains and green copper corrosion inside. The airbag module itself tested normal, but resistance across the harness wires at the connector was 0.5Ω (short circuit). Water ingress during wading caused a short circuit, and the airbag may have sustained internal damage. Repair: Cleaned the connector pins thoroughly and replaced the seal. Replaced the passenger side airbag (due to potential internal short circuit from water ingress). Re-wrapped and waterproofed the wiring harness. Fault resolved.
Original source ↗
BYD DTC AI Analysis

Metal debris in the ACM connector caused a false short-circuit fault.

✓
Symptom: After starting the vehicle, the message "Please check SRS system" appears intermittently. DTC B163B1A sets as a current code and returns sporadically after clearing, with no specific pattern. Diagnosis: Measured the passenger side airbag and wiring harness resistance – both 2.1Ω (normal). Inspected the SRS control module connector (under the centre console) and found metal debris inside, likely from a previous repair, causing a short between the B163B circuit pins. Resolution: Thoroughly cleaned the ACM connector interior with precision instrument cleaner, blew out debris with an air gun, verified the pins were not deformed, and reconnected. The fault has not returned.
Original source ↗
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: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.