UAE
AU
B167800

This DTC indicates the SRS electronic control unit detects a functional fault in the Left Rear Side Impact Sensor (mounted in the lower left B-pillar or inside the left rear quarter panel) — Atto 3

Safety System

This DTC indicates the SRS electronic control unit detects a functional fault in the Left Rear Side Impact Sensor (mounted in the lower left B-pillar or inside the left rear quarter panel).

Specifically, the ECU receives no valid acceleration signal, the signal exceeds the normal threshold (typically 0.5-4.5V), or the system detects an open or short circuit.

This sensor monitors side-impact acceleration on the left rear of the vehicle.

The ECU uses this signal to determine whether to deploy the left curtain airbag and rear side airbag.

When this fault occurs, the system enters fail-safe mode, illuminates the airbag warning light, and disables the related side airbags, significantly increasing the risk of occupant protection failure during a side collision.

3
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Left rear sensor intermittently reporting fault after wading

✓
2018 Qin Pro DM. Owner reported the airbag warning light would intermittently come on during rain or after washing. VDS scan showed active code B167800. Removed the left B-pillar lower trim, found water inside the sensor connector and green copper corrosion on the pins. Traced to deteriorated door seals allowing water ingress along the wiring harness. Cleaned harness terminals, replaced the sensor (internally moisture-damaged), rewrapped the harness and adjusted the waterproof tape position. Fault resolved.
BYD DTC AI Analysis

Open circuit in wiring harness following accident repair caused fault

✓
2019 Qin Pro (petrol). After a left rear side collision, an independent workshop repaired the vehicle. After delivery, the airbag light stayed on. Diagnosis found current DTC B167800 and no voltage at the sensor terminals. Tracing the wiring harness revealed a clamping plate had crushed it during the inner B-pillar repair, breaking the power wire. Repair involved soldering and heat-shrinking the harness, rerouting the wiring to avoid the crush point, and clearing the fault code. The system returned to normal.
BYD DTC AI Analysis

Sensor ageing caused signal drift

✓
The SRS warning light suddenly came on in a 2018 Qin Pro DM with 120,000 km and no collision history. The diagnostic scan tool displayed code B167800. Checked the wiring harness and connectors and found no faults. Measured the sensor's static resistance and found it normal. However, oscilloscope monitoring revealed abnormal noise in the signal output. Determined this was due to internal accelerometer degradation in the sensor. Replaced the left rear side impact sensor and performed the sensor matching procedure. Fault resolved.
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.