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B16E8-00

This DTC indicates a short to ground in the signal circuit of the Supplemental Restraint System (SRS) Middle Rear Impact Sensor — Atto 8

Safety System

This DTC indicates a short to ground in the signal circuit of the Supplemental Restraint System (SRS) Middle Rear Impact Sensor.

The sensor mounts in the center of the rear bumper or rear longitudinal rail area.

Electrically, the insulation resistance between the sensor signal wire (typically a LIN communication or analog signal line) and body ground drops below the threshold (generally <1Ω).

This causes the SRS control unit (ACU) to continuously receive an abnormally low voltage signal.

This fault forces the SRS into fail-safe mode.

As a result, the system may fail to accurately detect rear impact acceleration, preventing the airbags, curtain airbags, or seat belt pretensioners from deploying in time during a rear-end collision.

Furthermore, the ACU may interpret the condition as a wiring fault and completely disable the rear impact monitoring function, illuminate the instrument panel SRS warning lamp, and downgrade the vehicle's passive safety system.

BYD Qin series models typically use a dual-axis accelerometer design for this sensor.

The ACU continuously registers a short to ground as 'abnormal circuit current' or 'signal voltage below lower limit'.

3
Cases Logged
Real-World Cases
BYD DTC AI Analysis

After water ingress, an internal short in the sensor caused the SRS light to stay on.

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A 2017 Qin EV300 illuminated the SRS warning light after driving through deep water in heavy rain. Stored fault code: B16E8-00 (middle rear impact sensor short to ground). No collision damage was found on the rear bumper, but water had entered the sensor connector upon removal. The sensor’s signal terminal to housing resistance measured 0.3 Ω, confirming an internal short from water ingress. Replaced the middle rear impact sensor and waterproofed the connector with conductive grease and a waterproof cover, clearing the fault. Cause: deteriorated sensor seal allowed water to seep in through the connector gap during wading.
BYD DTC AI Analysis

Wiring harness chafing after accident repair caused intermittent fault.

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A non-authorised workshop repaired this 2018 Qin EV450 following a minor rear-end collision. One month later, the SRS warning light began illuminating intermittently. Diagnosis revealed DTC B16E8-00 as an intermittent active fault. Inspection of the rear impact sensor wiring harness routing found that the previous repair had not secured the harness correctly. A metal edge at the spare wheel well mounting bracket had cut through the insulation, allowing the wire to intermittently contact the body ground when driving over bumps. Repaired the damaged harness section, re-routed the wiring to specification, and protected it with a rubber protective sleeve, which completely resolved the fault.
BYD DTC AI Analysis

Connector corrosion caused signal short to ground.

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After three years of use in a coastal area, a 2017 Qin 100 showed an SRS warning light, with DTC B16E8-00 stored. Inspection found severe oxidation on the pins of the rear impact sensor connector (located inside the rear bumper). Green copper corrosion formed a low-resistance path (measured 12Ω) between the signal pin and the connector housing (ground). Cleaned the connector pins and socket, applied electronic contact cleaner, and replaced terminals where necessary. After cleaning, resistance returned to normal (>2kΩ). Cleared the DTC and the system returned to normal. Advised the owner to periodically check the sealing condition of underbody wiring harness connectors.
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: Community This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.