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B16E0

DTC B16E0 indicates a short to ground in the Left Rear Impact Sensor signal circuit within the airbag system (SRS) — Seal U

Safety System

DTC B16E0 indicates a short to ground in the Left Rear Impact Sensor signal circuit within the airbag system (SRS).

This sensor typically mounts in the left rear C-pillar, the left side of the rear bumper, or the inside of the left rear fender to monitor left rear collision acceleration.

A "short to ground" means the insulation resistance between the sensor signal line and body ground (GND) falls below the standard value (typically <1Ω).

This causes the SRS control unit (ACU) to detect a continuous low-voltage signal (approaching 0V), preventing it from acquiring normal acceleration change signals.

This fault forces the SRS into fail-safe mode, disabling the deployment function of the left rear side airbags (side curtain or rear seat airbags).

In extreme cases, this condition causes unintended airbag deployment or failure to deploy during a collision, posing a severe safety hazard.

4
Cases Logged
Real-World Cases
BYD DTC AI Analysis

Left rear impact sensor shorted after wading through water in Song MAX.

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Vehicle: 2019 Song MAX DM, 32,000 km. Symptom: Dashboard SRS warning light permanently illuminated. Scan tool retrieved DTC B16E0. History: Vehicle waded through water to half wheel-hub depth one week prior. Investigation revealed significant water ingress in the sensor connector on the inner side of the left rear bumper, with pins oxidised and blackened. Disassembly found the connector seal had aged, causing poor sealing. Repair: Cleaned connector pins using electrical contact cleaner and lint-free cloth. Replaced sensor (internal moisture damage). Applied dielectric grease to the connector and wrapped with waterproof tape. Fault resolved.
BYD DTC AI Analysis

Yuan EV wiring harness pinched and shorted after accident repair

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2019 Yuan EV535. Repaired at a workshop after a minor left-rear collision. After repair, SRS warning light on, DTC B16E0 stored. Diagnosis: Impact sensor in correct position and tested normal, but signal wire to ground measured 0.3 Ω. Investigation found the workshop had not secured the wiring harness in its retaining clip when refitting the rear bumper. A mounting screw pinched the harness and damaged the insulation. Repair: Cut out the damaged harness section, soldered in an extension wire, insulated with double-layer heat-shrink tubing, then rerouted and secured the harness to specification. Fault cleared.
BYD DTC AI Analysis

Tang DM left rear C-pillar wiring harness chafed, intermittent short circuit

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Model: 2021 Tang DM. Intermittent SRS warning light; DTC B16E0 appears intermittently. Diagnosis: Initial circuit measurements normal, but wiggling the harness caused a sudden resistance change. Removed and inspected the left rear C-pillar trim panel. Found the sensor harness rubber grommet had dislodged where it passes through the sheet metal hole. Long-term chafing against the sharp metal edge had exposed the copper conductors. Repair: Repaired the damaged harness section, reinstalled the rubber grommet (secured with sealant), and added corrugated tubing at the chafing point for protection. Multiple road tests — fault did not recur.
BYD DTC AI Analysis

Qin Pro sensor internal circuit breakdown

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Model: 2020 Qin Pro (petrol). No collision history; SRS light suddenly came on. Diagnosis: Measured signal wire voltage at the sensor connector to earth: 0V (normal: 2.5V). Disconnected the sensor, measured harness resistance to earth: infinite (normal). However, the sensor’s signal terminal had continuity to its housing. Disassembled the sensor and found burn marks on the internal PCB. Root cause: internal zener diode breakdown shorted to earth. Repair: Replaced with OEM left rear impact sensor (P/N ...), performed SRS configuration coding and matching. Fault resolved.
Other Seal U 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: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.