AU
B167B

DTC B167B indicates the Supplemental Restraint System (SRS) detects an unintended low-resistance connection (short to ground) between the Right Rear Side Impact Sensor signal circuit and vehicle ground (GND) — Atto 8

Safety System

DTC B167B indicates the Supplemental Restraint System (SRS) detects an unintended low-resistance connection (short to ground) between the Right Rear Side Impact Sensor signal circuit and vehicle ground (GND).

This sensor typically mounts in the right C-pillar, rear rocker panel, or rear seat side panel area to monitor side-impact acceleration at the right rear of the vehicle.

During a short to ground, the SRS control module detects an abnormal drop in sensor voltage (approaching 0V) and registers a sensor circuit fault.

This fault forces the SRS into a degraded mode: the right side airbag and curtain airbag may fail to deploy during a collision, or the system may falsely trigger its fail-safe mechanism, keeping the airbag warning lamp illuminated and severely compromising passive safety.

4
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Physical damage to the wiring harness: Long-term vibration and chafing of the right rear wiring harness near the door sill, C-pillar, or seat rail damages the insulation, allowing the wire to directly contact the body metal and create a short to ground.
  • 2Connector fault: improperly locked sensor connector, aged sealing ring causing water ingress and corrosion, or bent pins causing a short circuit between the signal and ground terminals.
  • 3Internal sensor short circuit: A fault in the collision sensor's internal piezoelectric element or processing circuit shorts the power supply/signal line to the housing (ground).
  • 4Improper repair: During accident repair or interior trim removal and installation, screws or clips crush or pierce the wiring harness, or improper securing allows the harness to contact sharp metal edges.
  • 5Environmental factors: Vehicle wading or water leaks causing water ingress into the right rear floor wiring harness connector, or rodents chewing through the wiring harness insulation.
What To Do
  • 1
    Safety preparation: Disconnect the 12V battery negative terminal. Wait at least 90 seconds to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 2
    Fault confirmation: Connect the diagnostic tool and read the freeze frame data. Verify the sensor voltage when the fault occurred (normally about 2.5V; close to 0V when shorted to ground). Clear the fault code and observe if it returns.
  • 3
    Locate the component: Remove the right C-pillar trim panel and rear door sill trim panel, then locate the right rear side impact sensor (usually has a black or yellow connector with a locking mechanism).
  • 4
    Circuit measurement: Disconnect the sensor connector. Use a multimeter to measure the resistance between the wiring harness side signal pin (usually the center pin) and body ground. If the resistance is <5Ω, confirm a short to ground; if the resistance is >1MΩ, the fault is in the sensor itself.
  • 5
    Wiring harness inspection: Inspect the sensor wiring harness along its routing. Focus on the insulation condition where the harness passes through body panel holes, runs past seat rails, and at retaining clips. Repair damaged sections and wrap with insulating tape, or replace the wiring harness.
  • 6
    Component inspection: If the wiring harness is normal, measure the resistance between the sensor pins. If abnormal, replace the sensor (match the part number to the vehicle model, such as Yuan EV, Tang).
  • 7
    System reset: After repair, restore connections, refit interior trim, and connect the battery. Use the diagnostic tool to perform 'SRS system self-learning' or 'sensor calibration' (required on some models). Clear fault codes and confirm normal system status.
Real-World Cases
BYD DTC AI Analysis

Corroded connectors in the water-damaged vehicle caused a short circuit.

✓
A 2020 BYD Song MAX presented with a constant airbag warning light after driving through flood water during heavy rain. Retrieved DTC B167B. Found clear water ingress in the right rear sill wiring harness connector, with pins showing green copper corrosion. Deteriorated door seals allowed rainwater to enter and pool at the sill harness connector. Repair: Cleaned corrosion from the connector, flushed with electronic cleaner and blow-dried, applied conductive grease, and replaced the seal. Fault cleared.
BYD DTC AI Analysis

Wiring harness pinched during accident repair, causing short circuit

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A 2019 BYD Yuan EV sustained scrape damage to the right rear side. After repair at an independent workshop, DTC B167B set. Inspection found the C-pillar trim panel fixing screws reinstalled during the repair were too long, piercing the side impact sensor harness sheath and causing the signal wire to directly contact the screw (earth). Replaced the damaged harness section, adjusted the screw length, rerouted the wiring to specification, and added protective sleeving.
BYD DTC AI Analysis

Sensor internal circuit fault

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A 2021 BYD Tang's airbag warning light came on suddenly during normal driving, with no collision history. The diagnostic tool displayed DTC B167B, which could not be cleared. Disconnected the sensor and measured harness-to-ground resistance: normal (infinite). Measured continuity between the sensor signal pin and its casing, confirming an internal PCB short. Replaced the right rear side impact sensor (part number: BYD-SRS-RRS-01); fault resolved. Cause: internal component thermal failure.
BYD DTC AI Analysis

Seat removal and installation chafed the wiring harness

✓
A 2019 BYD Qin Pro developed an intermittent B167B fault following replacement of the right rear seat cover. Inspection revealed the technician had not disconnected the sensor connector before removing the seat; forced pulling pinched the wiring harness at the seat hinge, damaging the insulation and exposing copper wire that contacted the seat frame. Repair: Repaired the damaged wiring, rerouted the harness clear of moving parts, added corrugated tube protection, and standardized the removal and installation procedures.
Other Atto 8 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.